Deletion in DataGrid

[loh]

Is there a event in the Windows Forms DataGrid similar to the BeforeDelete event in VB6 DataGrid? I would like to display a message box to confirm the deletion. How can I achieve that?

[Clay Burch]

One was you can catch the Delete key is to override the DataGrid's PreProcessMessage. Here is a code snippet.

public class MyDataGrid : DataGrid
{
	const int WM_KEYDOWN = 0x100;

	public override bool PreProcessMessage(	ref Message msg )
	}
		Keys keyCode = (Keys)(int)msg.WParam & Keys.KeyCode;
		if(msg.Msg == WM_KEYDOWN && keyCode == Keys.Delete)
		{
			if(MessageBox.Show("Delete this row?", 
				"", MessageBoxButtons.YesNo) == DialogResult.No)
			return true;
		}	
		return base.PreProcessMessage(ref msg);
	}
}

[loh]

Thx Clay for this very useful tip.

I notice that this message will still be fired when the AllowDelete property of the dataview that is bound to the grid is set to false. Though answering Yes or No has no effect. How can I add in a condition that if AllowDelete = false, no delete confirm message will be display?

Thanks in advance.

[Clay Burch]

As long as you are sure the DataSource is a DataView, you could directly test for AllowDelete in the override.

if(msg.Msg == WM_KEYDOWN
&& keyCode == Keys.Delete
&& ((DataView) this.DataSource).AllowDelete)
{
if(MessageBox.Show("Delete this row?",
"", MessageBoxButtons.YesNo) == DialogResult.No)
return true;
}

Regards,

Clay