Hide expand/collapse image in hierarchical RadGridView
| Product Version | Product | Author | Last modified |
|---|---|---|---|
| Q2 2010 SP1 | RadGridView for WinForms | Nikolay Diyanov | July 27, 2010 |
PROBLEM
When RadGridView displays hierarchical data, you expand/collapse child levels in the hierarchy with the help of GridGroupExpanderCellElement containing an expand/collapse image. However, when you do not have child data for certain rows, you may not want to show the expand/collapse images in the GridGroupExpanderCellElement.
SOLUTION
First of all, we will create a method which returns true if there is child data and false if there is no child data for a parent row:
private bool IsExpandable(GridViewRowInfo rowInfo)
{
if (rowInfo.ChildRows != null && rowInfo.ChildRows.Count > 0)
{
return true;
}
return false;
}
Private Function IsExpandable(ByVal rowInfo As GridViewRowInfo) As Boolean
If rowInfo.ChildRows IsNot Nothing AndAlso rowInfo.ChildRows.Count > 0 Then
Return True
End If
Return False
End Function
Next, we will subscribe to the ViewCellFormatting and ChildViewExpanding events of RadGridView. In ViewCellFormatting we will hide the expand/collapse image while in the ChildViewExpanding we will prevent a row from being expanded if there is no child data:
private void radGridView1_ViewCellFormatting(object sender, CellFormattingEventArgs e)
{
GridGroupExpanderCellElement cell = e.CellElement as GridGroupExpanderCellElement;
if (cell != null && e.CellElement.RowElement is GridDataRowElement)
{
if (!IsExpandable(cell.RowInfo))
{
cell.Expander.Visibility = Telerik.WinControls.ElementVisibility.Hidden;
}
else
{
cell.Expander.Visibility = Telerik.WinControls.ElementVisibility.Visible;
}
}
}
private void radGridView1_ChildViewExpanding(object sender, ChildViewExpandingEventArgs e)
{
e.Cancel = !IsExpandable(e.ParentRow);
}
Private Sub radGridView1_ViewCellFormatting(ByVal sender As Object, ByVal e As CellFormattingEventArgs)
Dim cell As GridGroupExpanderCellElement = TryCast(e.CellElement, GridGroupExpanderCellElement)
If cell IsNot Nothing AndAlso TypeOf e.CellElement.RowElement Is GridDataRowElement Then
If Not IsExpandable(cell.RowInfo) Then
cell.Expander.Visibility = Telerik.WinControls.ElementVisibility.Hidden
Else
cell.Expander.Visibility = Telerik.WinControls.ElementVisibility.Visible
End If
End If
End Sub
Private Sub radGridView1_ChildViewExpanding(ByVal sender As Object, ByVal e As ChildViewExpandingEventArgs)
e.Cancel = Not IsExpandable(e.ParentRow)
End Sub