Problem with combobox cell of GridDataBoundGrid

[David Bosak]

I am working with Combobox cell of GridDataBoundGrid But I don''t want users to delete the selected value of Combobox cell. Please let me know how to do that?

Thanks,

[Administrator]

You can handle the grid.Model.ClearingCells event and set e.Handled = true if e.RangeList holds a cell that you do not want to clear.

Here is a little snippet that does not clear anything that includes column 2.

private void Model_ClearingCells(object sender, GridClearingCellsEventArgs e)
{
	if(e.RangeList.AnyRangeIntersects(GridRangeInfo.Col(2)))
		e.Handled = true; //don''t let the grid handle it
}

[David Bosak]

when I delete the value of combobox cell, the application does not go through your code (I meant the application doesn''t raise that event). Please help!

[Administrator]

This event should be hit when your user selects a range of cells (by mousing down and dragging several cells) and presses the delete key. If this is what is not working for you, can you tell us how to see this problem in one of our samples, or upload a sample showing the problem. Also indicate the version of our libraries that you are using.

Now if your user is editing the combobox entry with the keyboard and blanks out the cell in this manner, the above event will not be hit. To catch this behavior, you can handle the CurrentCellValidating event, and if grid.CurrentCell.Renderer.ControlText.Length = 0, then set e.Cancel = true. This should prevent your user from leaving an empty cell that they have edited.

[David Bosak]

In your example ComboBox_CellValue.zip.
- running example
- double click on Combobox cell (the cell Text is selected all)
- press ''Delete'' key (the Text will be deteted)

How can I prevent the deletion above?

Thanks,

[Administrator]

I am not sure exactly what sample you are referring to: "In your example ComboBox_CellValue.zip". Did you get it from a particular forum link or Direct Trac incident?

I think you can handle this problem by :
1) in Form.Load, subscribe to the KeyDown event of the embedded textbox of the cellrenderer.

GridComboBoxCellRenderer cr = this.gridDataBoundGrid1.CellRenderers["ComboBox"] as GridComboBoxCellRenderer;
if(cr != null)
{
	cr.EditPart.KeyDown += new KeyEventHandler(EditPart_KeyDown);
}

2) Use a handler similar to :

private void EditPart_KeyDown(object sender, KeyEventArgs e)
{
	TextBoxBase tb = sender as TextBoxBase;
	if(tb != null && e.KeyCode == Keys.Delete
		&& tb.SelectionLength == tb.TextLength)
	{
		e.Handled = true;
	}
}

[Administrator]

Thanks for your help!