Windows Forms FAQ resources

5. Windows Forms Datagrid

5.51 How can I force the vertical scrollbar in my DataGrid to always be visible?

Derive a DataGrid. In your derived grid, add a handler for the VertScrollBar.VisibleChanged event. In your handler, if the scrollbar is not visible, size it and position it, and then show it. The code below assumes no horizontal scrollbar is necessary. If it is present, you would have to adjust the sizing code.

public class MyDataGrid : DataGrid

{

public MyDataGrid()

{

//make scrollbar visible & hook up handler

this.VertScrollBar.Visible = true;

this.VertScrollBar.VisibleChanged += new EventHandler(ShowScrollBars);

}

private int CAPTIONHEIGHT = 21;

private int BORDERWIDTH = 2;

private void ShowScrollBars(object sender, EventArgs e)

{

if(!this.VertScrollBar.Visible)

{

int width = this.VertScrollBar.Width;

this.VertScrollBar.Location = new Point(this.ClientRectangle.Width - width - BORDERWIDTH, CAPTIONHEIGHT);

this.VertScrollBar.Size = new Size(width, this.ClientRectangle.Height - CAPTIONHEIGHT - BORDERWIDTH);

this.VertScrollBar.Show();

}

VB.NET

Public Class MyDataGrid

Inherits DataGrid

Public Sub New()

'make scrollbar visible & hook up handler

Me.VertScrollBar.Visible = True

AddHandler Me.VertScrollBar.VisibleChanged, AddressOf ShowScrollBars

End Sub 'New

Private CAPTIONHEIGHT As Integer = 21

Private BORDERWIDTH As Integer = 2

Private Sub ShowScrollBars(sender As Object, e As EventArgs)

If Not Me.VertScrollBar.Visible Then

Dim width As Integer = Me.VertScrollBar.Width

Me.VertScrollBar.Location = New Point(Me.ClientRectangle.Width - width - BORDERWIDTH, CAPTIONHEIGHT)

Me.VertScrollBar.Size = New Size(width, Me.ClientRectangle.Height - CAPTIONHEIGHT - BORDERWIDTH)

Me.VertScrollBar.Show()

End If

End Sub 'ShowScrollBars

End Class 'MyDataGrid