DataGridView causing problems

T

Tony K

VB 2005 - Windows Vista

I have a form that seems to lock up when the number of rows exceed the
height of the datagridview. The following code executes when data is
received through the serial port (ie. barcode scanning). It seems that
everything works GREAT and processes as it was meant to be until the rows
exceed the display area. I have 7 columns. The Description column is the
only column with the AutoSizeMode set to Fill. The datagridview is docked
to the top. DataSource and DataMember for the DGV is not set to any
dataset.

I have the vertical scrollbar property set but it does not show up most of
the time. When/If it does, when I try and utilize the scrollbar, it locks
up the application immediately. I don't understand but I think it has to do
with the following method.


Sub ReceiveData(ByVal msg As String) 'Called after serial port has
received data and trimmed the value
CheckForIllegalCrossThreadCalls = False
description = Nothing 'form instance variable
loc = Nothing
Dim cmmInvMan As OleDbCommand
Dim strSQL As String
Dim drdTest As OleDbDataReader
Dim cnnInvMan As OleDbConnection = New
OleDbConnection(My.Settings.Inventory_management_databaseConnectionString)
cnnInvMan.Open()

strSQL = "SELECT * FROM Products WHERE ProductIDNumber = '" & msg &
"'"
cmmInvMan = New OleDbCommand(strSQL, cnnInvMan)
drdTest = cmmInvMan.ExecuteReader
Do While drdTest.Read
prodIDNum = CInt(drdTest.Item("ProductID"))
description = drdTest.Item("ProductDescription").ToString
loc = drdTest.Item("ProductLocation").ToString
minimumOnHand = CInt(drdTest.Item("ReorderLevel"))
maximumOnHand = CInt(drdTest.Item("MinimumRequired"))
Loop

drdTest.Close()

strSQL = "SELECT SUM(UnitsReceived) - SUM(UnitsSold) -
SUM(UnitsShrinkage) AS UnitsOnHand " & _
"FROM [" &
Me.Inventory_management_databaseDataSet.Inventory_Transactions.TableName &
"] WHERE (ProductID = " & prodIDNum & ")"

cmmInvMan = New OleDbCommand(strSQL, cnnInvMan)
drdTest = cmmInvMan.ExecuteReader
Do While drdTest.Read
Try
units = CInt(drdTest.Item("UnitsOnHand"))
Catch ex As InvalidCastException
units = 0
End Try
Loop

drdTest.Close()
cnnInvMan.Close()

Dim value As Integer
Dim duplicateRow As DataGridViewRow

For Each duplicateRow In Me.DataGridView1.Rows
If duplicateRow.Cells(0).Value Is Nothing Then Exit For
If duplicateRow.Cells(0).Value.ToString = msg Then
'MessageBox.Show(duplicateRow.Cells(1).ToString)
value = CInt(duplicateRow.Cells(4).Value)
value += 1
duplicateRow.Cells(4).Value = value.ToString
'unitsScanned
If duplicateRow.Cells(1).Value Is Nothing Then 'description
column
duplicateRow.Cells(1).Value = description
End If
If duplicateRow.Cells(3).Value Is Nothing Then 'UnitsOnHand
duplicateRow.Cells(3).Value = units.ToString
End If
If duplicateRow.Cells(2).Value Is Nothing Then 'location
duplicateRow.Cells(2).Value = loc
End If
If duplicateRow.Cells(5).Value Is Nothing Then 'minOnHand
duplicateRow.Cells(5).Value = minimumOnHand.ToString
End If
If duplicateRow.Cells(6).Value Is Nothing Then 'maxOnHand
duplicateRow.Cells(6).Value = maximumOnHand.ToString
End If
Exit Sub
End If
Next

Dim row As String() = {msg, description, loc, units.ToString, "1",
minimumOnHand.ToString, maximumOnHand.ToString}
Me.DataGridView1.Rows.Add(row)
End Sub

TIA,
Tony K.
 
C

Cor Ligthert[MVP]

Tony,

Try to avoid working direct with the DataGridView. That is only a UI, not a
datacollection.

Use datasources where for VB 2005 and the DataGridView the datatable is in
my idea the best and use for retrieving Data the dataadapter (or
tableadabter) as those give you the best performance.

Work then direct in the underlying DataSource (DataTable)

Be aware that setting something to nothing is a little bit strange.
Try to declare as less global as possible, because a unnecessary global
variable gives only confusion and uses more memory.

Cor

Tony K said:
VB 2005 - Windows Vista

I have a form that seems to lock up when the number of rows exceed the
height of the datagridview. The following code executes when data is
received through the serial port (ie. barcode scanning). It seems that
everything works GREAT and processes as it was meant to be until the rows
exceed the display area. I have 7 columns. The Description column is the
only column with the AutoSizeMode set to Fill. The datagridview is docked
to the top. DataSource and DataMember for the DGV is not set to any
dataset.

I have the vertical scrollbar property set but it does not show up most of
the time. When/If it does, when I try and utilize the scrollbar, it locks
up the application immediately. I don't understand but I think it has to
do with the following method.


Sub ReceiveData(ByVal msg As String) 'Called after serial port has
received data and trimmed the value
CheckForIllegalCrossThreadCalls = False
description = Nothing 'form instance variable
loc = Nothing
Dim cmmInvMan As OleDbCommand
Dim strSQL As String
Dim drdTest As OleDbDataReader
Dim cnnInvMan As OleDbConnection = New
OleDbConnection(My.Settings.Inventory_management_databaseConnectionString)
cnnInvMan.Open()

strSQL = "SELECT * FROM Products WHERE ProductIDNumber = '" & msg &
"'"
cmmInvMan = New OleDbCommand(strSQL, cnnInvMan)
drdTest = cmmInvMan.ExecuteReader
Do While drdTest.Read
prodIDNum = CInt(drdTest.Item("ProductID"))
description = drdTest.Item("ProductDescription").ToString
loc = drdTest.Item("ProductLocation").ToString
minimumOnHand = CInt(drdTest.Item("ReorderLevel"))
maximumOnHand = CInt(drdTest.Item("MinimumRequired"))
Loop

drdTest.Close()

strSQL = "SELECT SUM(UnitsReceived) - SUM(UnitsSold) -
SUM(UnitsShrinkage) AS UnitsOnHand " & _
"FROM [" &
Me.Inventory_management_databaseDataSet.Inventory_Transactions.TableName &
"] WHERE (ProductID = " & prodIDNum & ")"

cmmInvMan = New OleDbCommand(strSQL, cnnInvMan)
drdTest = cmmInvMan.ExecuteReader
Do While drdTest.Read
Try
units = CInt(drdTest.Item("UnitsOnHand"))
Catch ex As InvalidCastException
units = 0
End Try
Loop

drdTest.Close()
cnnInvMan.Close()

Dim value As Integer
Dim duplicateRow As DataGridViewRow

For Each duplicateRow In Me.DataGridView1.Rows
If duplicateRow.Cells(0).Value Is Nothing Then Exit For
If duplicateRow.Cells(0).Value.ToString = msg Then
'MessageBox.Show(duplicateRow.Cells(1).ToString)
value = CInt(duplicateRow.Cells(4).Value)
value += 1
duplicateRow.Cells(4).Value = value.ToString 'unitsScanned
If duplicateRow.Cells(1).Value Is Nothing Then
'description column
duplicateRow.Cells(1).Value = description
End If
If duplicateRow.Cells(3).Value Is Nothing Then
'UnitsOnHand
duplicateRow.Cells(3).Value = units.ToString
End If
If duplicateRow.Cells(2).Value Is Nothing Then 'location
duplicateRow.Cells(2).Value = loc
End If
If duplicateRow.Cells(5).Value Is Nothing Then 'minOnHand
duplicateRow.Cells(5).Value = minimumOnHand.ToString
End If
If duplicateRow.Cells(6).Value Is Nothing Then 'maxOnHand
duplicateRow.Cells(6).Value = maximumOnHand.ToString
End If
Exit Sub
End If
Next

Dim row As String() = {msg, description, loc, units.ToString, "1",
minimumOnHand.ToString, maximumOnHand.ToString}
Me.DataGridView1.Rows.Add(row)
End Sub

TIA,
Tony K.
Click to expand...
 
T

Tony K

Thank you Cor. I'll make the changes.

Tony K.

Cor Ligthert said:
Tony,

Try to avoid working direct with the DataGridView. That is only a UI, not
a datacollection.

Use datasources where for VB 2005 and the DataGridView the datatable is in
my idea the best and use for retrieving Data the dataadapter (or
tableadabter) as those give you the best performance.

Work then direct in the underlying DataSource (DataTable)

Be aware that setting something to nothing is a little bit strange.
Try to declare as less global as possible, because a unnecessary global
variable gives only confusion and uses more memory.

Cor

Tony K said:
VB 2005 - Windows Vista

I have a form that seems to lock up when the number of rows exceed the
height of the datagridview. The following code executes when data is
received through the serial port (ie. barcode scanning). It seems that
everything works GREAT and processes as it was meant to be until the rows
exceed the display area. I have 7 columns. The Description column is
the only column with the AutoSizeMode set to Fill. The datagridview is
docked to the top. DataSource and DataMember for the DGV is not set to
any dataset.

I have the vertical scrollbar property set but it does not show up most
of the time. When/If it does, when I try and utilize the scrollbar, it
locks up the application immediately. I don't understand but I think it
has to do with the following method.


Sub ReceiveData(ByVal msg As String) 'Called after serial port has
received data and trimmed the value
CheckForIllegalCrossThreadCalls = False
description = Nothing 'form instance variable
loc = Nothing
Dim cmmInvMan As OleDbCommand
Dim strSQL As String
Dim drdTest As OleDbDataReader
Dim cnnInvMan As OleDbConnection = New
OleDbConnection(My.Settings.Inventory_management_databaseConnectionString)
cnnInvMan.Open()

strSQL = "SELECT * FROM Products WHERE ProductIDNumber = '" & msg
& "'"
cmmInvMan = New OleDbCommand(strSQL, cnnInvMan)
drdTest = cmmInvMan.ExecuteReader
Do While drdTest.Read
prodIDNum = CInt(drdTest.Item("ProductID"))
description = drdTest.Item("ProductDescription").ToString
loc = drdTest.Item("ProductLocation").ToString
minimumOnHand = CInt(drdTest.Item("ReorderLevel"))
maximumOnHand = CInt(drdTest.Item("MinimumRequired"))
Loop

drdTest.Close()

strSQL = "SELECT SUM(UnitsReceived) - SUM(UnitsSold) -
SUM(UnitsShrinkage) AS UnitsOnHand " & _
"FROM [" &
Me.Inventory_management_databaseDataSet.Inventory_Transactions.TableName
& "] WHERE (ProductID = " & prodIDNum & ")"

cmmInvMan = New OleDbCommand(strSQL, cnnInvMan)
drdTest = cmmInvMan.ExecuteReader
Do While drdTest.Read
Try
units = CInt(drdTest.Item("UnitsOnHand"))
Catch ex As InvalidCastException
units = 0
End Try
Loop

drdTest.Close()
cnnInvMan.Close()

Dim value As Integer
Dim duplicateRow As DataGridViewRow

For Each duplicateRow In Me.DataGridView1.Rows
If duplicateRow.Cells(0).Value Is Nothing Then Exit For
If duplicateRow.Cells(0).Value.ToString = msg Then
'MessageBox.Show(duplicateRow.Cells(1).ToString)
value = CInt(duplicateRow.Cells(4).Value)
value += 1
duplicateRow.Cells(4).Value = value.ToString 'unitsScanned
If duplicateRow.Cells(1).Value Is Nothing Then
'description column
duplicateRow.Cells(1).Value = description
End If
If duplicateRow.Cells(3).Value Is Nothing Then
'UnitsOnHand
duplicateRow.Cells(3).Value = units.ToString
End If
If duplicateRow.Cells(2).Value Is Nothing Then 'location
duplicateRow.Cells(2).Value = loc
End If
If duplicateRow.Cells(5).Value Is Nothing Then 'minOnHand
duplicateRow.Cells(5).Value = minimumOnHand.ToString
End If
If duplicateRow.Cells(6).Value Is Nothing Then
'maxOnHand
duplicateRow.Cells(6).Value = maximumOnHand.ToString
End If
Exit Sub
End If
Next

Dim row As String() = {msg, description, loc, units.ToString, "1",
minimumOnHand.ToString, maximumOnHand.ToString}
Me.DataGridView1.Rows.Add(row)
End Sub

TIA,
Tony K.
Click to expand...
Click to expand...
 
R

Rich P

Hello,

Instead of trying to display the date you retrieve from the serial port
directly in the datagridview, do this: Create an empty dataset in the
DataSources tab of Visual Studio - next to the Explorer/Solution tab
(usually on the right side of the screen or wherever you have set the
Solution explorer). In the datasources tab just use the wizard to
create an empty dataset and don't select any tables. Once you have an
empty dataset you can then edit the dateset (right click on the new
dataset and select edit from the context menu). Once you are inside the
dataset window - right click and select Add Table. Create a table that
will contains the fields you need - you an assign datatypes, but the
default is string. Name the table something - the default name is
"DataTable1"

Now, in your form code, you can declare a dataset var as the dataset you
just created

Dim dsData As MyNewDataset 'or whatever you name the dataset in the
datasources tab

dsData = New MyNewDataset
Dim dr As DataRow = dsData.DataTable1.NewRow
dr("col1") = firstItemyouretrieved
dr("col2") = nextItemyouretrieved
dr("col3") = nextnextItem
...
dsData.DataTable1.Rows.Add(dr)
...
fill the table with your data
...

datagridview.DataSource = dsData.DataTable1

You can then use the dataAdapter to transfer the data to a server DB.
Note: the dataAdapter doesn't work with an OLEDB db (MS Access) - only
works with Server DBs. For OLEDB you can use an ADO.Net command object
- works almost the same as classic ADO command object.


Rich
 

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