Column Count

[Doug Bell]

Hi,

I need to create a function that will return the number of columns in a
passed reference to a DataView.

I can find the number of columns in its underlying Data table but have not
been able to find a way of determining the column count in the DataView.

Thanks for any assistance.

Doug

 

[Chris, Master of all Things Insignificant]

I didn't think the two could be different. How do you lose columns when you
apply the table to the dataview?

Chris

 

[Doug Bell]

Chris,
Sorry, I didn't really explain that very well.

What I am trying to do is determine the number of columns displayed in a
datagrid.
The datagrid has a grid style applied to it.

Doug

 

[Chris, Master of all Things Insignificant]

Well This is strange and I don't know what's going on with it, but

Grab a hold of the TableStyles object off your datagrid after the gridstyle
is added. Then look at the Gridcolumnstyles. This holds all your columns,
but for some reason there isn't a count method on it. However it is really
there and I've used it. So the code below will give you the count, you can
also itterate through all the columns there. Anyone say why the Count
method isn't displayed in Intellisense?

Hope it helps

MessageBox.Show(DGrid.TableStyles(0).GridColumnStyles.Count())

Chris

 

[Doug Bell]

Thanks Chris,

That is great! And I was a little surprised there was not a count method but
did not think to try it without it being selectable from the intelisense.
Now I can build a re-usable function to size the last column to the
remaining grid width irespective of the selected grid style.

Doug

 

[Chris, Master of all Things Insignificant]

That's an interesting idea. How are you figuring out how much space is left
on the grid for that column to fill?

Chris

 

[Guest]

An alternate solution is to resize all the column widths to make them larger
proportionally to their current width and the remaining blank space to fill

 

[Doug Bell]

Chris,
Sorry for delay, I had a guy come to fix my garage door.
I am still finding my way with Dot Net but what I am doing is:

1. get number of columns intNumCols
2. get desired width (intDesiredWidth) and Uused width (intUsedWidth)

Dim intDesiredWidth as Integer = MyGrid.Width
For each ctrl as Control In MyGrid.Controls
If TypeOf ctrl Is VScrollBar Then
If ctrl.Visible Then
intDesiredWidth = intDesiredWidth - ctrl.Width
EndIf
Exit For
EndIf
Next

intDesiredWidth=intDesiredWidth +39 'Fudge determined by trial & error 39
worked for me

Dim dv1 As DataView = CType(MyGrid.DataSource, DataView)
Dim stStyle As String = dv1.Table.TableName.ToString
Dim i as Integer = 0
Do While i <intNumCols - 1
intUsedWidth = intUsedWidth +
MyGrid.TableStyles(stStyle).GridColumnStyles(i).Width
i = i + 1
Loop
intDesiredWidth = intDesiredWidth - intUsedWidth

If intDesiredWidth >0 Then
Do Until i = 0
If MyGrid.TableStyles(stStyle).GridColumnStyle(i).Width > 0 Then
'This is the last Visible Column
MyGrid.TableStyles(stStyle).GridColumnStyle(i).Width =
intDesiredWidth
ExitDo
EndIf
i = i - 1
Loop
EndIf


Doug

 

[Cor Ligthert]

Dough,

When you still are looking for your original question
\\\
Dim x As Integer = dv.Table.Columns.Count
Dim y As String = dv.Table.Columns(0).ColumnName
'and any other information about a column
///

I hope this helps?

Cor