OK
I checked the archives on sorting a listview control and from there I read
the quickstart tutorial. I
duplicated the code from the tutorial, thinking I understood it fairly well,
and modified as necessary such as changing the name of the listview control
to the name I used for my listview control.

On the following line:
Dim clickedCol As ColHeader = CType(Me.lvwItemList.Columns(e.Column),
ColHeader)

I get this error:

An unhandled exception of type 'System.InvalidCastException' occurred in
testprogram.exe

What the heck does that mean?



ColHeader is defined with the following code:

Public Class ColHeader

Inherits ColumnHeader

Public ascending As Boolean

Public Sub New(ByVal [text] As String, ByVal width As Integer, ByVal
align As HorizontalAlignment, ByVal asc As Boolean)

Me.Text = [text]

Me.Width = width

Me.TextAlign = align

Me.ascending = asc

End Sub

End Class



James

In that event, does e have several types of objects that it can potentially
be (Header, Row, Footer, etc)? You may need to make sure you check that it
is in fact a Header object before trying to cast it. Typically this is done
with the use of a switch block (select case for vb).

Thanks,

Matt


"JamesL" <(E-Mail Removed)> wrote in message
news:%Tspe.953$(E-Mail Removed)...
> OK
> I checked the archives on sorting a listview control and from there I read
> the quickstart tutorial. I
> duplicated the code from the tutorial, thinking I understood it fairly
> well,
> and modified as necessary such as changing the name of the listview
> control
> to the name I used for my listview control.
>
> On the following line:
> Dim clickedCol As ColHeader = CType(Me.lvwItemList.Columns(e.Column),
> ColHeader)
>
> I get this error:
>
> An unhandled exception of type 'System.InvalidCastException' occurred in
> testprogram.exe
>
> What the heck does that mean?
>
>
>
> ColHeader is defined with the following code:
>
> Public Class ColHeader
>
> Inherits ColumnHeader
>
> Public ascending As Boolean
>
> Public Sub New(ByVal [text] As String, ByVal width As Integer,
> ByVal
> align As HorizontalAlignment, ByVal asc As Boolean)
>
> Me.Text = [text]
>
> Me.Width = width
>
> Me.TextAlign = align
>
> Me.ascending = asc
>
> End Sub
>
> End Class
>
>
>
> James
>
>

Ok, I have been debugging and all I find is that the error definitely occurs
in the line:

CType(Me.lvwItemList.Columns(e.Column)

I am clicking on the column header of the listview control to trigger this
code. It is direct form the Quickstart but I cannot figure out what the
problem is. How would I check that is in fact a Header object? I
understand the select case function, but what property will tell me if it is
a header object? and since I am clinking the header wouldn't it have to be
a header object?

James Lysaght


"ME" <(E-Mail Removed)> wrote in message
news:ALCdnQXmu_UM8DvfRVn-(E-Mail Removed)...
> In that event, does e have several types of objects that it can
> potentially be (Header, Row, Footer, etc)? You may need to make sure you
> check that it is in fact a Header object before trying to cast it.
> Typically this is done with the use of a switch block (select case for
> vb).
>
> Thanks,
>
> Matt
>
>
> "JamesL" <(E-Mail Removed)> wrote in message
> news:%Tspe.953$(E-Mail Removed)...
>> OK
>> I checked the archives on sorting a listview control and from there I
>> read the quickstart tutorial. I
>> duplicated the code from the tutorial, thinking I understood it fairly
>> well,
>> and modified as necessary such as changing the name of the listview
>> control
>> to the name I used for my listview control.
>>
>> On the following line:
>> Dim clickedCol As ColHeader = CType(Me.lvwItemList.Columns(e.Column),
>> ColHeader)
>>
>> I get this error:
>>
>> An unhandled exception of type 'System.InvalidCastException' occurred in
>> testprogram.exe
>>
>> What the heck does that mean?
>>
>>
>>
>> ColHeader is defined with the following code:
>>
>> Public Class ColHeader
>>
>> Inherits ColumnHeader
>>
>> Public ascending As Boolean
>>
>> Public Sub New(ByVal [text] As String, ByVal width As Integer,
>> ByVal
>> align As HorizontalAlignment, ByVal asc As Boolean)
>>
>> Me.Text = [text]
>>
>> Me.Width = width
>>
>> Me.TextAlign = align
>>
>> Me.ascending = asc
>>
>> End Sub
>>
>> End Class
>>
>>
>>
>> James
>>
>>
>
>

> CType(Me.lvwItemList.Columns(e.Column)
Your statement seems incomplete (i.e. I'd expect a compile time error)

In any case no cast is required. Assuming a listview with columns if you
place this is in the ColumnClick event handler it should work
Me.Text = lvwItemList.Columns(e.Column).Text

If you are asking for something else please show the full code with expected
and actual results

Cheers
Daniel
--
http://www.danielmoth.com/Blog/


"JamesL" <(E-Mail Removed)> wrote in message
news:X1Epe.1181$(E-Mail Removed)...
> Ok, I have been debugging and all I find is that the error definitely
> occurs in the line:
>
> CType(Me.lvwItemList.Columns(e.Column)
>
> I am clicking on the column header of the listview control to trigger this
> code. It is direct form the Quickstart but I cannot figure out what the
> problem is. How would I check that is in fact a Header object? I
> understand the select case function, but what property will tell me if it
> is a header object? and since I am clinking the header wouldn't it have
> to be a header object?
>
> James Lysaght
>
>
> "ME" <(E-Mail Removed)> wrote in message
> news:ALCdnQXmu_UM8DvfRVn-(E-Mail Removed)...
>> In that event, does e have several types of objects that it can
>> potentially be (Header, Row, Footer, etc)? You may need to make sure you
>> check that it is in fact a Header object before trying to cast it.
>> Typically this is done with the use of a switch block (select case for
>> vb).
>>
>> Thanks,
>>
>> Matt
>>
>>
>> "JamesL" <(E-Mail Removed)> wrote in message
>> news:%Tspe.953$(E-Mail Removed)...
>>> OK
>>> I checked the archives on sorting a listview control and from there I
>>> read the quickstart tutorial. I
>>> duplicated the code from the tutorial, thinking I understood it fairly
>>> well,
>>> and modified as necessary such as changing the name of the listview
>>> control
>>> to the name I used for my listview control.
>>>
>>> On the following line:
>>> Dim clickedCol As ColHeader = CType(Me.lvwItemList.Columns(e.Column),
>>> ColHeader)
>>>
>>> I get this error:
>>>
>>> An unhandled exception of type 'System.InvalidCastException' occurred in
>>> testprogram.exe
>>>
>>> What the heck does that mean?
>>>
>>>
>>>
>>> ColHeader is defined with the following code:
>>>
>>> Public Class ColHeader
>>>
>>> Inherits ColumnHeader
>>>
>>> Public ascending As Boolean
>>>
>>> Public Sub New(ByVal [text] As String, ByVal width As Integer,
>>> ByVal
>>> align As HorizontalAlignment, ByVal asc As Boolean)
>>>
>>> Me.Text = [text]
>>>
>>> Me.Width = width
>>>
>>> Me.TextAlign = align
>>>
>>> Me.ascending = asc
>>>
>>> End Sub
>>>
>>> End Class
>>>
>>>
>>>
>>> James
>>>
>>>
>>
>>
>
>

Thanks, but I am not trying to capture the column.text which would give me
the text appearing in the header of the column. I am trying to capture the
entire ColumnHeader and assign it to a new custom created class ColHeader.
ColHeader should inherit ColumnHeader and then add the ascending property to
it to use for sorting.

The expected result is that I should be able to sort the listview in
ascending or descending order based on column by clicking the column header.

The actual result is the CastType error: An unhandled exception of type
'System.InvalidCastException' occurred in testprogram.exe

ColHeader is defined with the following code:

Public Class ColHeader
Inherits ColumnHeader
Public ascending As Boolean
Public Sub New(ByVal [Text] As String, ByVal width As Integer, ByVal
align As HorizontalAlignment, ByVal asc As Boolean)
Me.Text = [Text]
Me.Width = width
Me.TextAlign = align
Me.ascending = asc
End Sub
End Class

Then in the column click event we have:

Private Sub lvwItemList_ColumnClick(ByVal sender As Object, ByVal e As
System.Windows.Forms.ColumnClickEventArgs) Handles lvwItemList.ColumnClick
' Create an instance of the ColHeader class.
Dim clickedCol As ColHeader = CType(Me.lvwItemList.Columns(e.Column),
ColHeader)

' Set the ascending property to sort in the opposite order.
clickedCol.ascending = Not clickedCol.ascending

' Get the number of items in the list.
Dim numItems As Integer = Me.lvwItemList.Items.Count

' Turn off display while data is repoplulated.
Me.lvwItemList.BeginUpdate()

' Populate an ArrayList with a SortWrapper of each list item.
Dim SortArray As New ArrayList
Dim i As Integer
For i = 0 To numItems - 1
SortArray.Add(New SortWrapper(Me.lvwItemList.Items(i), e.Column))
Next i

' Sort the elements in the ArrayList using a new instance of the
SortComparer
' class. The parameters are the starting index, the length of the range
to sort,
' and the IComparer implementation to use for comparing elements. Note
that
' the IComparer implementation (SortComparer) requires the sort
' direction for its constructor; true if ascending, othwise false.
SortArray.Sort(0, SortArray.Count, New
SortWrapper.SortComparer(clickedCol.ascending))

' Clear the list, and repopulate with the sorted items.
Me.lvwItemList.Items.Clear()
Dim z As Integer
For z = 0 To numItems - 1
Me.lvwItemList.Items.Add(CType(SortArray(z), SortWrapper).sortItem)
Next z

' Turn display back on.
Me.lvwItemList.EndUpdate()

End Sub

The SortWrapper is defined as:

' An instance of the SortWrapper class is created for
'each item and added to the ArrayList for sorting.
Public Class SortWrapper

Friend sortItem As ListViewItem
Friend sortColumn As Integer

' A SortWrapper requires the item and the index of the clicked column.
Public Sub New(ByVal Item As ListViewItem, ByVal iColumn As Integer)
sortItem = Item
sortColumn = iColumn
End Sub

' Text property for getting the text of an item.
Public ReadOnly Property [Text]() As String
Get
Return sortItem.SubItems(sortColumn).Text
End Get
End Property

' Implementation of the IComparer
' interface for sorting ArrayList items.
Public Class SortComparer
Implements IComparer

Private ascending As Boolean

' Constructor requires the sort order;
' true if ascending, otherwise descending.
Public Sub New(ByVal asc As Boolean)
Me.ascending = asc
End Sub

' Implemnentation of the IComparer:Compare
' method for comparing two objects.
Public Function [Compare](ByVal x As Object, ByVal y As Object) As
Integer Implements IComparer.Compare
Dim xItem As SortWrapper = CType(x, SortWrapper)
Dim yItem As SortWrapper = CType(y, SortWrapper)
Dim xText As String =
xItem.sortItem.SubItems(xItem.sortColumn).Text
Dim yText As String =
yItem.sortItem.SubItems(yItem.sortColumn).Text
Return xText.CompareTo(yText) * IIf(Me.ascending, 1, -1)
End Function

End Class

End Class

All of this is direct from the quickstart tutorial. All I changed was the
name of the listview control.

James Lysaght


"Daniel Moth" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>> CType(Me.lvwItemList.Columns(e.Column)
> Your statement seems incomplete (i.e. I'd expect a compile time error)
>
> In any case no cast is required. Assuming a listview with columns if you
> place this is in the ColumnClick event handler it should work
> Me.Text = lvwItemList.Columns(e.Column).Text
>
> If you are asking for something else please show the full code with
> expected and actual results
>
> Cheers
> Daniel
> --
> http://www.danielmoth.com/Blog/
>
>
> "JamesL" <(E-Mail Removed)> wrote in message
> news:X1Epe.1181$(E-Mail Removed)...
>> Ok, I have been debugging and all I find is that the error definitely
>> occurs in the line:
>>
>> CType(Me.lvwItemList.Columns(e.Column)
>>
>> I am clicking on the column header of the listview control to trigger
>> this code. It is direct form the Quickstart but I cannot figure out what
>> the problem is. How would I check that is in fact a Header object? I
>> understand the select case function, but what property will tell me if it
>> is a header object? and since I am clinking the header wouldn't it have
>> to be a header object?
>>
>> James Lysaght
>>
>>
>> "ME" <(E-Mail Removed)> wrote in message
>> news:ALCdnQXmu_UM8DvfRVn-(E-Mail Removed)...
>>> In that event, does e have several types of objects that it can
>>> potentially be (Header, Row, Footer, etc)? You may need to make sure
>>> you check that it is in fact a Header object before trying to cast it.
>>> Typically this is done with the use of a switch block (select case for
>>> vb).
>>>
>>> Thanks,
>>>
>>> Matt
>>>
>>>
>>> "JamesL" <(E-Mail Removed)> wrote in message
>>> news:%Tspe.953$(E-Mail Removed)...
>>>> OK
>>>> I checked the archives on sorting a listview control and from there I
>>>> read the quickstart tutorial. I
>>>> duplicated the code from the tutorial, thinking I understood it fairly
>>>> well,
>>>> and modified as necessary such as changing the name of the listview
>>>> control
>>>> to the name I used for my listview control.
>>>>
>>>> On the following line:
>>>> Dim clickedCol As ColHeader = CType(Me.lvwItemList.Columns(e.Column),
>>>> ColHeader)
>>>>
>>>> I get this error:
>>>>
>>>> An unhandled exception of type 'System.InvalidCastException' occurred
>>>> in
>>>> testprogram.exe
>>>>
>>>> What the heck does that mean?
>>>>
>>>>
>>>>
>>>> ColHeader is defined with the following code:
>>>>
>>>> Public Class ColHeader
>>>>
>>>> Inherits ColumnHeader
>>>>
>>>> Public ascending As Boolean
>>>>
>>>> Public Sub New(ByVal [text] As String, ByVal width As Integer,
>>>> ByVal
>>>> align As HorizontalAlignment, ByVal asc As Boolean)
>>>>
>>>> Me.Text = [text]
>>>>
>>>> Me.Width = width
>>>>
>>>> Me.TextAlign = align
>>>>
>>>> Me.ascending = asc
>>>>
>>>> End Sub
>>>>
>>>> End Class
>>>>
>>>>
>>>>
>>>> James
>>>>
>>>>
>>>
>>>
>>
>>
>

I do not see where you adding ColHeader. You have to initiate and add
ColHeader and not ColumnHeader:

lvwItemList.Columns.Add(new ColHeader())


--
Sergey Bogdanov
http://www.sergeybogdanov.com


JamesL wrote:
> Thanks, but I am not trying to capture the column.text which would give me
> the text appearing in the header of the column. I am trying to capture the
> entire ColumnHeader and assign it to a new custom created class ColHeader.
> ColHeader should inherit ColumnHeader and then add the ascending property to
> it to use for sorting.
>
> The expected result is that I should be able to sort the listview in
> ascending or descending order based on column by clicking the column header.
>
> The actual result is the CastType error: An unhandled exception of type
> 'System.InvalidCastException' occurred in testprogram.exe
>
> ColHeader is defined with the following code:
>
> Public Class ColHeader
> Inherits ColumnHeader
> Public ascending As Boolean
> Public Sub New(ByVal [Text] As String, ByVal width As Integer, ByVal
> align As HorizontalAlignment, ByVal asc As Boolean)
> Me.Text = [Text]
> Me.Width = width
> Me.TextAlign = align
> Me.ascending = asc
> End Sub
> End Class
>
> Then in the column click event we have:
>
> Private Sub lvwItemList_ColumnClick(ByVal sender As Object, ByVal e As
> System.Windows.Forms.ColumnClickEventArgs) Handles lvwItemList.ColumnClick
> ' Create an instance of the ColHeader class.
> Dim clickedCol As ColHeader = CType(Me.lvwItemList.Columns(e.Column),
> ColHeader)
>
> ' Set the ascending property to sort in the opposite order.
> clickedCol.ascending = Not clickedCol.ascending
>
> ' Get the number of items in the list.
> Dim numItems As Integer = Me.lvwItemList.Items.Count
>
> ' Turn off display while data is repoplulated.
> Me.lvwItemList.BeginUpdate()
>
> ' Populate an ArrayList with a SortWrapper of each list item.
> Dim SortArray As New ArrayList
> Dim i As Integer
> For i = 0 To numItems - 1
> SortArray.Add(New SortWrapper(Me.lvwItemList.Items(i), e.Column))
> Next i
>
> ' Sort the elements in the ArrayList using a new instance of the
> SortComparer
> ' class. The parameters are the starting index, the length of the range
> to sort,
> ' and the IComparer implementation to use for comparing elements. Note
> that
> ' the IComparer implementation (SortComparer) requires the sort
> ' direction for its constructor; true if ascending, othwise false.
> SortArray.Sort(0, SortArray.Count, New
> SortWrapper.SortComparer(clickedCol.ascending))
>
> ' Clear the list, and repopulate with the sorted items.
> Me.lvwItemList.Items.Clear()
> Dim z As Integer
> For z = 0 To numItems - 1
> Me.lvwItemList.Items.Add(CType(SortArray(z), SortWrapper).sortItem)
> Next z
>
> ' Turn display back on.
> Me.lvwItemList.EndUpdate()
>
> End Sub
>
> The SortWrapper is defined as:
>
> ' An instance of the SortWrapper class is created for
> 'each item and added to the ArrayList for sorting.
> Public Class SortWrapper
>
> Friend sortItem As ListViewItem
> Friend sortColumn As Integer
>
> ' A SortWrapper requires the item and the index of the clicked column.
> Public Sub New(ByVal Item As ListViewItem, ByVal iColumn As Integer)
> sortItem = Item
> sortColumn = iColumn
> End Sub
>
> ' Text property for getting the text of an item.
> Public ReadOnly Property [Text]() As String
> Get
> Return sortItem.SubItems(sortColumn).Text
> End Get
> End Property
>
> ' Implementation of the IComparer
> ' interface for sorting ArrayList items.
> Public Class SortComparer
> Implements IComparer
>
> Private ascending As Boolean
>
> ' Constructor requires the sort order;
> ' true if ascending, otherwise descending.
> Public Sub New(ByVal asc As Boolean)
> Me.ascending = asc
> End Sub
>
> ' Implemnentation of the IComparer:Compare
> ' method for comparing two objects.
> Public Function [Compare](ByVal x As Object, ByVal y As Object) As
> Integer Implements IComparer.Compare
> Dim xItem As SortWrapper = CType(x, SortWrapper)
> Dim yItem As SortWrapper = CType(y, SortWrapper)
> Dim xText As String =
> xItem.sortItem.SubItems(xItem.sortColumn).Text
> Dim yText As String =
> yItem.sortItem.SubItems(yItem.sortColumn).Text
> Return xText.CompareTo(yText) * IIf(Me.ascending, 1, -1)
> End Function
>
> End Class
>
> End Class
>
> All of this is direct from the quickstart tutorial. All I changed was the
> name of the listview control.
>
> James Lysaght
>
>
> "Daniel Moth" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>
>>>CType(Me.lvwItemList.Columns(e.Column)
>>
>>Your statement seems incomplete (i.e. I'd expect a compile time error)
>>
>>In any case no cast is required. Assuming a listview with columns if you
>>place this is in the ColumnClick event handler it should work
>>Me.Text = lvwItemList.Columns(e.Column).Text
>>
>>If you are asking for something else please show the full code with
>>expected and actual results
>>
>>Cheers
>>Daniel
>>--
>>http://www.danielmoth.com/Blog/
>>
>>
>>"JamesL" <(E-Mail Removed)> wrote in message
>>news:X1Epe.1181$(E-Mail Removed)...
>>
>>>Ok, I have been debugging and all I find is that the error definitely
>>>occurs in the line:
>>>
>>>CType(Me.lvwItemList.Columns(e.Column)
>>>
>>>I am clicking on the column header of the listview control to trigger
>>>this code. It is direct form the Quickstart but I cannot figure out what
>>>the problem is. How would I check that is in fact a Header object? I
>>>understand the select case function, but what property will tell me if it
>>>is a header object? and since I am clinking the header wouldn't it have
>>>to be a header object?
>>>
>>>James Lysaght
>>>
>>>
>>>"ME" <(E-Mail Removed)> wrote in message
>>>news:ALCdnQXmu_UM8DvfRVn-(E-Mail Removed)...
>>>
>>>>In that event, does e have several types of objects that it can
>>>>potentially be (Header, Row, Footer, etc)? You may need to make sure
>>>>you check that it is in fact a Header object before trying to cast it.
>>>>Typically this is done with the use of a switch block (select case for
>>>>vb).
>>>>
>>>>Thanks,
>>>>
>>>>Matt
>>>>
>>>>
>>>>"JamesL" <(E-Mail Removed)> wrote in message
>>>>news:%Tspe.953$(E-Mail Removed)...
>>>>
>>>>>OK
>>>>>I checked the archives on sorting a listview control and from there I
>>>>>read the quickstart tutorial. I
>>>>>duplicated the code from the tutorial, thinking I understood it fairly
>>>>>well,
>>>>>and modified as necessary such as changing the name of the listview
>>>>>control
>>>>>to the name I used for my listview control.
>>>>>
>>>>>On the following line:
>>>>>Dim clickedCol As ColHeader = CType(Me.lvwItemList.Columns(e.Column),
>>>>>ColHeader)
>>>>>
>>>>>I get this error:
>>>>>
>>>>>An unhandled exception of type 'System.InvalidCastException' occurred
>>>>>in
>>>>>testprogram.exe
>>>>>
>>>>>What the heck does that mean?
>>>>>
>>>>>
>>>>>
>>>>>ColHeader is defined with the following code:
>>>>>
>>>>>Public Class ColHeader
>>>>>
>>>>> Inherits ColumnHeader
>>>>>
>>>>> Public ascending As Boolean
>>>>>
>>>>> Public Sub New(ByVal [text] As String, ByVal width As Integer,
>>>>>ByVal
>>>>>align As HorizontalAlignment, ByVal asc As Boolean)
>>>>>
>>>>> Me.Text = [text]
>>>>>
>>>>> Me.Width = width
>>>>>
>>>>> Me.TextAlign = align
>>>>>
>>>>> Me.ascending = asc
>>>>>
>>>>> End Sub
>>>>>
>>>>>End Class
>>>>>
>>>>>
>>>>>
>>>>>James
>>>>>
>>>>>
>>>>
>>>>
>>>
>
>

I found the quickstart you are talking about (you provided no link):
http://samples.gotdotnet.com/quickst...stViewSort.src

See how in the ctor the code show explicit addition of ColHeader objects
(not the default ColumnHeader which the designer will do if you use the UI).
Are you doing the same? Show us all the code...

Cheers
Daniel
--
http://www.danielmoth.com/Blog/


"JamesL" <(E-Mail Removed)> wrote in message
news:xOVre.4746$(E-Mail Removed)...
> Thanks, but I am not trying to capture the column.text which would give me
> the text appearing in the header of the column. I am trying to capture
> the entire ColumnHeader and assign it to a new custom created class
> ColHeader. ColHeader should inherit ColumnHeader and then add the
> ascending property to it to use for sorting.
>
> The expected result is that I should be able to sort the listview in
> ascending or descending order based on column by clicking the column
> header.
>
> The actual result is the CastType error: An unhandled exception of type
> 'System.InvalidCastException' occurred in testprogram.exe
>
> ColHeader is defined with the following code:
>
> Public Class ColHeader
> Inherits ColumnHeader
> Public ascending As Boolean
> Public Sub New(ByVal [Text] As String, ByVal width As Integer, ByVal
> align As HorizontalAlignment, ByVal asc As Boolean)
> Me.Text = [Text]
> Me.Width = width
> Me.TextAlign = align
> Me.ascending = asc
> End Sub
> End Class
>
> Then in the column click event we have:
>
> Private Sub lvwItemList_ColumnClick(ByVal sender As Object, ByVal e As
> System.Windows.Forms.ColumnClickEventArgs) Handles lvwItemList.ColumnClick
> ' Create an instance of the ColHeader class.
> Dim clickedCol As ColHeader = CType(Me.lvwItemList.Columns(e.Column),
> ColHeader)
>
> ' Set the ascending property to sort in the opposite order.
> clickedCol.ascending = Not clickedCol.ascending
>
> ' Get the number of items in the list.
> Dim numItems As Integer = Me.lvwItemList.Items.Count
>
> ' Turn off display while data is repoplulated.
> Me.lvwItemList.BeginUpdate()
>
> ' Populate an ArrayList with a SortWrapper of each list item.
> Dim SortArray As New ArrayList
> Dim i As Integer
> For i = 0 To numItems - 1
> SortArray.Add(New SortWrapper(Me.lvwItemList.Items(i), e.Column))
> Next i
>
> ' Sort the elements in the ArrayList using a new instance of the
> SortComparer
> ' class. The parameters are the starting index, the length of the range
> to sort,
> ' and the IComparer implementation to use for comparing elements. Note
> that
> ' the IComparer implementation (SortComparer) requires the sort
> ' direction for its constructor; true if ascending, othwise false.
> SortArray.Sort(0, SortArray.Count, New
> SortWrapper.SortComparer(clickedCol.ascending))
>
> ' Clear the list, and repopulate with the sorted items.
> Me.lvwItemList.Items.Clear()
> Dim z As Integer
> For z = 0 To numItems - 1
> Me.lvwItemList.Items.Add(CType(SortArray(z), SortWrapper).sortItem)
> Next z
>
> ' Turn display back on.
> Me.lvwItemList.EndUpdate()
>
> End Sub
>
> The SortWrapper is defined as:
>
> ' An instance of the SortWrapper class is created for
> 'each item and added to the ArrayList for sorting.
> Public Class SortWrapper
>
> Friend sortItem As ListViewItem
> Friend sortColumn As Integer
>
> ' A SortWrapper requires the item and the index of the clicked column.
> Public Sub New(ByVal Item As ListViewItem, ByVal iColumn As Integer)
> sortItem = Item
> sortColumn = iColumn
> End Sub
>
> ' Text property for getting the text of an item.
> Public ReadOnly Property [Text]() As String
> Get
> Return sortItem.SubItems(sortColumn).Text
> End Get
> End Property
>
> ' Implementation of the IComparer
> ' interface for sorting ArrayList items.
> Public Class SortComparer
> Implements IComparer
>
> Private ascending As Boolean
>
> ' Constructor requires the sort order;
> ' true if ascending, otherwise descending.
> Public Sub New(ByVal asc As Boolean)
> Me.ascending = asc
> End Sub
>
> ' Implemnentation of the IComparer:Compare
> ' method for comparing two objects.
> Public Function [Compare](ByVal x As Object, ByVal y As Object) As
> Integer Implements IComparer.Compare
> Dim xItem As SortWrapper = CType(x, SortWrapper)
> Dim yItem As SortWrapper = CType(y, SortWrapper)
> Dim xText As String =
> xItem.sortItem.SubItems(xItem.sortColumn).Text
> Dim yText As String =
> yItem.sortItem.SubItems(yItem.sortColumn).Text
> Return xText.CompareTo(yText) * IIf(Me.ascending, 1, -1)
> End Function
>
> End Class
>
> End Class
>
> All of this is direct from the quickstart tutorial. All I changed was the
> name of the listview control.
>
> James Lysaght
>
>
> "Daniel Moth" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>>> CType(Me.lvwItemList.Columns(e.Column)
>> Your statement seems incomplete (i.e. I'd expect a compile time error)
>>
>> In any case no cast is required. Assuming a listview with columns if you
>> place this is in the ColumnClick event handler it should work
>> Me.Text = lvwItemList.Columns(e.Column).Text
>>
>> If you are asking for something else please show the full code with
>> expected and actual results
>>
>> Cheers
>> Daniel
>> --
>> http://www.danielmoth.com/Blog/
>>
>>
>> "JamesL" <(E-Mail Removed)> wrote in message
>> news:X1Epe.1181$(E-Mail Removed)...
>>> Ok, I have been debugging and all I find is that the error definitely
>>> occurs in the line:
>>>
>>> CType(Me.lvwItemList.Columns(e.Column)
>>>
>>> I am clicking on the column header of the listview control to trigger
>>> this code. It is direct form the Quickstart but I cannot figure out
>>> what the problem is. How would I check that is in fact a Header object?
>>> I understand the select case function, but what property will tell me if
>>> it is a header object? and since I am clinking the header wouldn't it
>>> have to be a header object?
>>>
>>> James Lysaght
>>>
>>>
>>> "ME" <(E-Mail Removed)> wrote in message
>>> news:ALCdnQXmu_UM8DvfRVn-(E-Mail Removed)...
>>>> In that event, does e have several types of objects that it can
>>>> potentially be (Header, Row, Footer, etc)? You may need to make sure
>>>> you check that it is in fact a Header object before trying to cast it.
>>>> Typically this is done with the use of a switch block (select case for
>>>> vb).
>>>>
>>>> Thanks,
>>>>
>>>> Matt
>>>>
>>>>
>>>> "JamesL" <(E-Mail Removed)> wrote in message
>>>> news:%Tspe.953$(E-Mail Removed)...
>>>>> OK
>>>>> I checked the archives on sorting a listview control and from there I
>>>>> read the quickstart tutorial. I
>>>>> duplicated the code from the tutorial, thinking I understood it fairly
>>>>> well,
>>>>> and modified as necessary such as changing the name of the listview
>>>>> control
>>>>> to the name I used for my listview control.
>>>>>
>>>>> On the following line:
>>>>> Dim clickedCol As ColHeader = CType(Me.lvwItemList.Columns(e.Column),
>>>>> ColHeader)
>>>>>
>>>>> I get this error:
>>>>>
>>>>> An unhandled exception of type 'System.InvalidCastException' occurred
>>>>> in
>>>>> testprogram.exe
>>>>>
>>>>> What the heck does that mean?
>>>>>
>>>>>
>>>>>
>>>>> ColHeader is defined with the following code:
>>>>>
>>>>> Public Class ColHeader
>>>>>
>>>>> Inherits ColumnHeader
>>>>>
>>>>> Public ascending As Boolean
>>>>>
>>>>> Public Sub New(ByVal [text] As String, ByVal width As Integer,
>>>>> ByVal
>>>>> align As HorizontalAlignment, ByVal asc As Boolean)
>>>>>
>>>>> Me.Text = [text]
>>>>>
>>>>> Me.Width = width
>>>>>
>>>>> Me.TextAlign = align
>>>>>
>>>>> Me.ascending = asc
>>>>>
>>>>> End Sub
>>>>>
>>>>> End Class
>>>>>
>>>>>
>>>>>
>>>>> James
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>
>

AH HA!!!! That's It!!!!

You hit it right there! I used the UI to add my column headers, I need to
add them in code so I get ColHeader objects instead...

I will experiment with that, I am sure that is the problem. It is obvious
to me now! Admittedly, I am feeling a little red in the face at the moment.
I should have caught that. Thanks a ton!

Sorry about forgetting to include the link to the quickstart: irresponsible
omission on my part. Thanks for looking it up!

James Lysaght

"Daniel Moth" <(E-Mail Removed)> wrote in message
news:%(E-Mail Removed)...
>I found the quickstart you are talking about (you provided no link):
> http://samples.gotdotnet.com/quickst...stViewSort.src
>
> See how in the ctor the code show explicit addition of ColHeader objects
> (not the default ColumnHeader which the designer will do if you use the
> UI). Are you doing the same? Show us all the code...
>
> Cheers
> Daniel
> --
> http://www.danielmoth.com/Blog/
>
>
> "JamesL" <(E-Mail Removed)> wrote in message
> news:xOVre.4746$(E-Mail Removed)...
>> Thanks, but I am not trying to capture the column.text which would give
>> me the text appearing in the header of the column. I am trying to
>> capture the entire ColumnHeader and assign it to a new custom created
>> class ColHeader. ColHeader should inherit ColumnHeader and then add the
>> ascending property to it to use for sorting.
>>
>> The expected result is that I should be able to sort the listview in
>> ascending or descending order based on column by clicking the column
>> header.
>>
>> The actual result is the CastType error: An unhandled exception of type
>> 'System.InvalidCastException' occurred in testprogram.exe
>>
>> ColHeader is defined with the following code:
>>
>> Public Class ColHeader
>> Inherits ColumnHeader
>> Public ascending As Boolean
>> Public Sub New(ByVal [Text] As String, ByVal width As Integer, ByVal
>> align As HorizontalAlignment, ByVal asc As Boolean)
>> Me.Text = [Text]
>> Me.Width = width
>> Me.TextAlign = align
>> Me.ascending = asc
>> End Sub
>> End Class
>>
>> Then in the column click event we have:
>>
>> Private Sub lvwItemList_ColumnClick(ByVal sender As Object, ByVal e As
>> System.Windows.Forms.ColumnClickEventArgs) Handles
>> lvwItemList.ColumnClick
>> ' Create an instance of the ColHeader class.
>> Dim clickedCol As ColHeader = CType(Me.lvwItemList.Columns(e.Column),
>> ColHeader)
>>
>> ' Set the ascending property to sort in the opposite order.
>> clickedCol.ascending = Not clickedCol.ascending
>>
>> ' Get the number of items in the list.
>> Dim numItems As Integer = Me.lvwItemList.Items.Count
>>
>> ' Turn off display while data is repoplulated.
>> Me.lvwItemList.BeginUpdate()
>>
>> ' Populate an ArrayList with a SortWrapper of each list item.
>> Dim SortArray As New ArrayList
>> Dim i As Integer
>> For i = 0 To numItems - 1
>> SortArray.Add(New SortWrapper(Me.lvwItemList.Items(i), e.Column))
>> Next i
>>
>> ' Sort the elements in the ArrayList using a new instance of the
>> SortComparer
>> ' class. The parameters are the starting index, the length of the
>> range to sort,
>> ' and the IComparer implementation to use for comparing elements. Note
>> that
>> ' the IComparer implementation (SortComparer) requires the sort
>> ' direction for its constructor; true if ascending, othwise false.
>> SortArray.Sort(0, SortArray.Count, New
>> SortWrapper.SortComparer(clickedCol.ascending))
>>
>> ' Clear the list, and repopulate with the sorted items.
>> Me.lvwItemList.Items.Clear()
>> Dim z As Integer
>> For z = 0 To numItems - 1
>> Me.lvwItemList.Items.Add(CType(SortArray(z),
>> SortWrapper).sortItem)
>> Next z
>>
>> ' Turn display back on.
>> Me.lvwItemList.EndUpdate()
>>
>> End Sub
>>
>> The SortWrapper is defined as:
>>
>> ' An instance of the SortWrapper class is created for
>> 'each item and added to the ArrayList for sorting.
>> Public Class SortWrapper
>>
>> Friend sortItem As ListViewItem
>> Friend sortColumn As Integer
>>
>> ' A SortWrapper requires the item and the index of the clicked column.
>> Public Sub New(ByVal Item As ListViewItem, ByVal iColumn As Integer)
>> sortItem = Item
>> sortColumn = iColumn
>> End Sub
>>
>> ' Text property for getting the text of an item.
>> Public ReadOnly Property [Text]() As String
>> Get
>> Return sortItem.SubItems(sortColumn).Text
>> End Get
>> End Property
>>
>> ' Implementation of the IComparer
>> ' interface for sorting ArrayList items.
>> Public Class SortComparer
>> Implements IComparer
>>
>> Private ascending As Boolean
>>
>> ' Constructor requires the sort order;
>> ' true if ascending, otherwise descending.
>> Public Sub New(ByVal asc As Boolean)
>> Me.ascending = asc
>> End Sub
>>
>> ' Implemnentation of the IComparer:Compare
>> ' method for comparing two objects.
>> Public Function [Compare](ByVal x As Object, ByVal y As Object) As
>> Integer Implements IComparer.Compare
>> Dim xItem As SortWrapper = CType(x, SortWrapper)
>> Dim yItem As SortWrapper = CType(y, SortWrapper)
>> Dim xText As String =
>> xItem.sortItem.SubItems(xItem.sortColumn).Text
>> Dim yText As String =
>> yItem.sortItem.SubItems(yItem.sortColumn).Text
>> Return xText.CompareTo(yText) * IIf(Me.ascending, 1, -1)
>> End Function
>>
>> End Class
>>
>> End Class
>>
>> All of this is direct from the quickstart tutorial. All I changed was
>> the name of the listview control.
>>
>> James Lysaght
>>
>>
>> "Daniel Moth" <(E-Mail Removed)> wrote in message
>> news:(E-Mail Removed)...
>>>> CType(Me.lvwItemList.Columns(e.Column)
>>> Your statement seems incomplete (i.e. I'd expect a compile time error)
>>>
>>> In any case no cast is required. Assuming a listview with columns if you
>>> place this is in the ColumnClick event handler it should work
>>> Me.Text = lvwItemList.Columns(e.Column).Text
>>>
>>> If you are asking for something else please show the full code with
>>> expected and actual results
>>>
>>> Cheers
>>> Daniel
>>> --
>>> http://www.danielmoth.com/Blog/
>>>
>>>
>>> "JamesL" <(E-Mail Removed)> wrote in message
>>> news:X1Epe.1181$(E-Mail Removed)...
>>>> Ok, I have been debugging and all I find is that the error definitely
>>>> occurs in the line:
>>>>
>>>> CType(Me.lvwItemList.Columns(e.Column)
>>>>
>>>> I am clicking on the column header of the listview control to trigger
>>>> this code. It is direct form the Quickstart but I cannot figure out
>>>> what the problem is. How would I check that is in fact a Header
>>>> object? I understand the select case function, but what property will
>>>> tell me if it is a header object? and since I am clinking the header
>>>> wouldn't it have to be a header object?
>>>>
>>>> James Lysaght
>>>>
>>>>
>>>> "ME" <(E-Mail Removed)> wrote in message
>>>> news:ALCdnQXmu_UM8DvfRVn-(E-Mail Removed)...
>>>>> In that event, does e have several types of objects that it can
>>>>> potentially be (Header, Row, Footer, etc)? You may need to make sure
>>>>> you check that it is in fact a Header object before trying to cast it.
>>>>> Typically this is done with the use of a switch block (select case for
>>>>> vb).
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Matt
>>>>>
>>>>>
>>>>> "JamesL" <(E-Mail Removed)> wrote in message
>>>>> news:%Tspe.953$(E-Mail Removed)...
>>>>>> OK
>>>>>> I checked the archives on sorting a listview control and from there I
>>>>>> read the quickstart tutorial. I
>>>>>> duplicated the code from the tutorial, thinking I understood it
>>>>>> fairly well,
>>>>>> and modified as necessary such as changing the name of the listview
>>>>>> control
>>>>>> to the name I used for my listview control.
>>>>>>
>>>>>> On the following line:
>>>>>> Dim clickedCol As ColHeader = CType(Me.lvwItemList.Columns(e.Column),
>>>>>> ColHeader)
>>>>>>
>>>>>> I get this error:
>>>>>>
>>>>>> An unhandled exception of type 'System.InvalidCastException' occurred
>>>>>> in
>>>>>> testprogram.exe
>>>>>>
>>>>>> What the heck does that mean?
>>>>>>
>>>>>>
>>>>>>
>>>>>> ColHeader is defined with the following code:
>>>>>>
>>>>>> Public Class ColHeader
>>>>>>
>>>>>> Inherits ColumnHeader
>>>>>>
>>>>>> Public ascending As Boolean
>>>>>>
>>>>>> Public Sub New(ByVal [text] As String, ByVal width As Integer,
>>>>>> ByVal
>>>>>> align As HorizontalAlignment, ByVal asc As Boolean)
>>>>>>
>>>>>> Me.Text = [text]
>>>>>>
>>>>>> Me.Width = width
>>>>>>
>>>>>> Me.TextAlign = align
>>>>>>
>>>>>> Me.ascending = asc
>>>>>>
>>>>>> End Sub
>>>>>>
>>>>>> End Class
>>>>>>
>>>>>>
>>>>>>
>>>>>> James
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>
>>
>

Yep! That did it! Problem solved, works like a charm! Exactly what I
wanted to accomplish.

I can't thank you enough!

James Lysaght

"JamesL" <(E-Mail Removed)> wrote in message
news:_wWre.4453$(E-Mail Removed)...
> AH HA!!!! That's It!!!!
>
> You hit it right there! I used the UI to add my column headers, I need to
> add them in code so I get ColHeader objects instead...
>
> I will experiment with that, I am sure that is the problem. It is obvious
> to me now! Admittedly, I am feeling a little red in the face at the
> moment. I should have caught that. Thanks a ton!
>
> Sorry about forgetting to include the link to the quickstart:
> irresponsible omission on my part. Thanks for looking it up!
>
> James Lysaght
>
> "Daniel Moth" <(E-Mail Removed)> wrote in message
> news:%(E-Mail Removed)...
>>I found the quickstart you are talking about (you provided no link):
>> http://samples.gotdotnet.com/quickst...stViewSort.src
>>
>> See how in the ctor the code show explicit addition of ColHeader objects
>> (not the default ColumnHeader which the designer will do if you use the
>> UI). Are you doing the same? Show us all the code...
>>
>> Cheers
>> Daniel
>> --
>> http://www.danielmoth.com/Blog/
>>
>>
>> "JamesL" <(E-Mail Removed)> wrote in message
>> news:xOVre.4746$(E-Mail Removed)...
>>> Thanks, but I am not trying to capture the column.text which would give
>>> me the text appearing in the header of the column. I am trying to
>>> capture the entire ColumnHeader and assign it to a new custom created
>>> class ColHeader. ColHeader should inherit ColumnHeader and then add the
>>> ascending property to it to use for sorting.
>>>
>>> The expected result is that I should be able to sort the listview in
>>> ascending or descending order based on column by clicking the column
>>> header.
>>>
>>> The actual result is the CastType error: An unhandled exception of type
>>> 'System.InvalidCastException' occurred in testprogram.exe
>>>
>>> ColHeader is defined with the following code:
>>>
>>> Public Class ColHeader
>>> Inherits ColumnHeader
>>> Public ascending As Boolean
>>> Public Sub New(ByVal [Text] As String, ByVal width As Integer, ByVal
>>> align As HorizontalAlignment, ByVal asc As Boolean)
>>> Me.Text = [Text]
>>> Me.Width = width
>>> Me.TextAlign = align
>>> Me.ascending = asc
>>> End Sub
>>> End Class
>>>
>>> Then in the column click event we have:
>>>
>>> Private Sub lvwItemList_ColumnClick(ByVal sender As Object, ByVal e As
>>> System.Windows.Forms.ColumnClickEventArgs) Handles
>>> lvwItemList.ColumnClick
>>> ' Create an instance of the ColHeader class.
>>> Dim clickedCol As ColHeader = CType(Me.lvwItemList.Columns(e.Column),
>>> ColHeader)
>>>
>>> ' Set the ascending property to sort in the opposite order.
>>> clickedCol.ascending = Not clickedCol.ascending
>>>
>>> ' Get the number of items in the list.
>>> Dim numItems As Integer = Me.lvwItemList.Items.Count
>>>
>>> ' Turn off display while data is repoplulated.
>>> Me.lvwItemList.BeginUpdate()
>>>
>>> ' Populate an ArrayList with a SortWrapper of each list item.
>>> Dim SortArray As New ArrayList
>>> Dim i As Integer
>>> For i = 0 To numItems - 1
>>> SortArray.Add(New SortWrapper(Me.lvwItemList.Items(i), e.Column))
>>> Next i
>>>
>>> ' Sort the elements in the ArrayList using a new instance of the
>>> SortComparer
>>> ' class. The parameters are the starting index, the length of the
>>> range to sort,
>>> ' and the IComparer implementation to use for comparing elements.
>>> Note that
>>> ' the IComparer implementation (SortComparer) requires the sort
>>> ' direction for its constructor; true if ascending, othwise false.
>>> SortArray.Sort(0, SortArray.Count, New
>>> SortWrapper.SortComparer(clickedCol.ascending))
>>>
>>> ' Clear the list, and repopulate with the sorted items.
>>> Me.lvwItemList.Items.Clear()
>>> Dim z As Integer
>>> For z = 0 To numItems - 1
>>> Me.lvwItemList.Items.Add(CType(SortArray(z),
>>> SortWrapper).sortItem)
>>> Next z
>>>
>>> ' Turn display back on.
>>> Me.lvwItemList.EndUpdate()
>>>
>>> End Sub
>>>
>>> The SortWrapper is defined as:
>>>
>>> ' An instance of the SortWrapper class is created for
>>> 'each item and added to the ArrayList for sorting.
>>> Public Class SortWrapper
>>>
>>> Friend sortItem As ListViewItem
>>> Friend sortColumn As Integer
>>>
>>> ' A SortWrapper requires the item and the index of the clicked
>>> column.
>>> Public Sub New(ByVal Item As ListViewItem, ByVal iColumn As Integer)
>>> sortItem = Item
>>> sortColumn = iColumn
>>> End Sub
>>>
>>> ' Text property for getting the text of an item.
>>> Public ReadOnly Property [Text]() As String
>>> Get
>>> Return sortItem.SubItems(sortColumn).Text
>>> End Get
>>> End Property
>>>
>>> ' Implementation of the IComparer
>>> ' interface for sorting ArrayList items.
>>> Public Class SortComparer
>>> Implements IComparer
>>>
>>> Private ascending As Boolean
>>>
>>> ' Constructor requires the sort order;
>>> ' true if ascending, otherwise descending.
>>> Public Sub New(ByVal asc As Boolean)
>>> Me.ascending = asc
>>> End Sub
>>>
>>> ' Implemnentation of the IComparer:Compare
>>> ' method for comparing two objects.
>>> Public Function [Compare](ByVal x As Object, ByVal y As Object)
>>> As Integer Implements IComparer.Compare
>>> Dim xItem As SortWrapper = CType(x, SortWrapper)
>>> Dim yItem As SortWrapper = CType(y, SortWrapper)
>>> Dim xText As String =
>>> xItem.sortItem.SubItems(xItem.sortColumn).Text
>>> Dim yText As String =
>>> yItem.sortItem.SubItems(yItem.sortColumn).Text
>>> Return xText.CompareTo(yText) * IIf(Me.ascending, 1, -1)
>>> End Function
>>>
>>> End Class
>>>
>>> End Class
>>>
>>> All of this is direct from the quickstart tutorial. All I changed was
>>> the name of the listview control.
>>>
>>> James Lysaght
>>>
>>>
>>> "Daniel Moth" <(E-Mail Removed)> wrote in message
>>> news:(E-Mail Removed)...
>>>>> CType(Me.lvwItemList.Columns(e.Column)
>>>> Your statement seems incomplete (i.e. I'd expect a compile time error)
>>>>
>>>> In any case no cast is required. Assuming a listview with columns if
>>>> you place this is in the ColumnClick event handler it should work
>>>> Me.Text = lvwItemList.Columns(e.Column).Text
>>>>
>>>> If you are asking for something else please show the full code with
>>>> expected and actual results
>>>>
>>>> Cheers
>>>> Daniel
>>>> --
>>>> http://www.danielmoth.com/Blog/
>>>>
>>>>
>>>> "JamesL" <(E-Mail Removed)> wrote in message
>>>> news:X1Epe.1181$(E-Mail Removed)...
>>>>> Ok, I have been debugging and all I find is that the error definitely
>>>>> occurs in the line:
>>>>>
>>>>> CType(Me.lvwItemList.Columns(e.Column)
>>>>>
>>>>> I am clicking on the column header of the listview control to trigger
>>>>> this code. It is direct form the Quickstart but I cannot figure out
>>>>> what the problem is. How would I check that is in fact a Header
>>>>> object? I understand the select case function, but what property will
>>>>> tell me if it is a header object? and since I am clinking the header
>>>>> wouldn't it have to be a header object?
>>>>>
>>>>> James Lysaght
>>>>>
>>>>>
>>>>> "ME" <(E-Mail Removed)> wrote in message
>>>>> news:ALCdnQXmu_UM8DvfRVn-(E-Mail Removed)...
>>>>>> In that event, does e have several types of objects that it can
>>>>>> potentially be (Header, Row, Footer, etc)? You may need to make sure
>>>>>> you check that it is in fact a Header object before trying to cast
>>>>>> it. Typically this is done with the use of a switch block (select
>>>>>> case for vb).
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Matt
>>>>>>
>>>>>>
>>>>>> "JamesL" <(E-Mail Removed)> wrote in message
>>>>>> news:%Tspe.953$(E-Mail Removed)...
>>>>>>> OK
>>>>>>> I checked the archives on sorting a listview control and from there
>>>>>>> I read the quickstart tutorial. I
>>>>>>> duplicated the code from the tutorial, thinking I understood it
>>>>>>> fairly well,
>>>>>>> and modified as necessary such as changing the name of the listview
>>>>>>> control
>>>>>>> to the name I used for my listview control.
>>>>>>>
>>>>>>> On the following line:
>>>>>>> Dim clickedCol As ColHeader =
>>>>>>> CType(Me.lvwItemList.Columns(e.Column),
>>>>>>> ColHeader)
>>>>>>>
>>>>>>> I get this error:
>>>>>>>
>>>>>>> An unhandled exception of type 'System.InvalidCastException'
>>>>>>> occurred in
>>>>>>> testprogram.exe
>>>>>>>
>>>>>>> What the heck does that mean?
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> ColHeader is defined with the following code:
>>>>>>>
>>>>>>> Public Class ColHeader
>>>>>>>
>>>>>>> Inherits ColumnHeader
>>>>>>>
>>>>>>> Public ascending As Boolean
>>>>>>>
>>>>>>> Public Sub New(ByVal [text] As String, ByVal width As
>>>>>>> Integer, ByVal
>>>>>>> align As HorizontalAlignment, ByVal asc As Boolean)
>>>>>>>
>>>>>>> Me.Text = [text]
>>>>>>>
>>>>>>> Me.Width = width
>>>>>>>
>>>>>>> Me.TextAlign = align
>>>>>>>
>>>>>>> Me.ascending = asc
>>>>>>>
>>>>>>> End Sub
>>>>>>>
>>>>>>> End Class
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> James
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>
>
>