wpf-6137-controls-and-libraries-data-grid-grouping-expanding-and-collapsing-group-rows.md
End users can expand or collapse group rows by clicking group buttons.
To expand a group row, use the GridControl.ExpandGroupRow method. A group row is specified by its handle. To expand the focused group row, use the GridViewBase.ExpandFocusedRow method. All group rows can be expanded using the GridControl.ExpandAllGroups method.
Users can press the Right Arrow or + key to expand the focused group row.
The GridControl.AutoExpandAllGroups property specifies whether all group rows are automatically expanded after each grouping operation.
Before a group row is expanded, the GridControl.GroupRowExpanding event is raised, which allows you to cancel the action. For instance, you can prevent an end user from expanding individual group rows. After a group row has been expanded, the GridControl.GroupRowExpanded event is raised.
To identify whether a group row is expanded, use the GridControl.IsGroupRowExpanded method.
To collapse the specified group row, use the GridControl.CollapseGroupRow method. To collapse the focused group row, use the GridViewBase.CollapseFocusedRow method. All group rows can be collapsed using the GridControl.CollapseAllGroups method.
Users can press the Left Arrow or - key to collapse the focused group row.
Before a group row is collapsed, the GridControl.GroupRowCollapsing event is raised, which allows you to cancel the action. After a group row has been collapsed, the GridControl.GroupRowCollapsed event is raised.
The following example does not allow users to collapse the Status: Invalidated group row and expand the Status: Delivered group row.
View Example: Forbid Expand and Collapse Operations for Group Rows
<dxg:GridControl x:Name="grid"
EndGrouping="OnEndGrouping"
GroupRowCollapsing="OnGroupRowCollapsing"
GroupRowCollapsed="OnGroupRowCollapsed"
GroupRowExpanding="OnGroupRowExpanding"
GroupRowExpanded="OnGroupRowExpanded">
<dxg:GridColumn FieldName="ProductName"/>
<dxg:GridColumn FieldName="Price"/>
<dxg:GridColumn FieldName="Discount"/>
<dxg:GridColumn FieldName="Status" GroupIndex="0" SortOrder="Descending"/>
<dxg:GridControl.View>
<dxg:TableView x:Name="view" GroupValueTemplateSelector="{StaticResource groupRowTemplateSelector}"/>
</dxg:GridControl.View>
</dxg:GridControl>
void OnEndGrouping(object sender, RoutedEventArgs e) {
if (grid.Columns[nameof(Invoice.Status)].GroupIndex == 0) {
var childRow = grid.FindRowByValue(grid.Columns[nameof(Invoice.Status)], InvoiceStatus.Invalidated);
var groupRow = grid.GetParentRowHandle(childRow);
grid.ExpandGroupRow(groupRow);
childRow = grid.FindRowByValue(grid.Columns[nameof(Invoice.Status)], InvoiceStatus.Delivered);
groupRow = grid.GetParentRowHandle(childRow);
grid.CollapseGroupRow(groupRow);
}
}
void OnGroupRowCollapsing(object sender, RowAllowEventArgs e) {
if (e.Row != null && grid.GetGroupRowValue(e.RowHandle).Equals(InvoiceStatus.Invalidated))
e.Allow = false;
}
void OnGroupRowCollapsed(object sender, RowEventArgs e) {
if (e.Row == null && grid.Columns[nameof(Invoice.Status)].GroupIndex == 0) {
var childRow = grid.FindRowByValue(grid.Columns[nameof(Invoice.Status)], InvoiceStatus.Invalidated);
var groupRow = grid.GetParentRowHandle(childRow);
grid.ExpandGroupRow(groupRow);
}
}
void OnGroupRowExpanding(object sender, RowAllowEventArgs e) {
if (e.Row != null && grid.GetGroupRowValue(e.RowHandle).Equals(InvoiceStatus.Delivered))
e.Allow = false;
}
void OnGroupRowExpanded(object sender, RowEventArgs e) {
if (e.Row == null && grid.Columns[nameof(Invoice.Status)].GroupIndex == 0) {
var childRow = grid.FindRowByValue(grid.Columns[nameof(Invoice.Status)], InvoiceStatus.Delivered);
var groupRow = grid.GetParentRowHandle(childRow);
grid.CollapseGroupRow(groupRow);
}
}
Private Sub OnEndGrouping(ByVal sender As Object, ByVal e As RoutedEventArgs)
If Me.grid.Columns(NameOf(Invoice.Status)).GroupIndex = 0 Then
Dim childRow = Me.grid.FindRowByValue(Me.grid.Columns(NameOf(Invoice.Status)), InvoiceStatus.Invalidated)
Dim groupRow = Me.grid.GetParentRowHandle(childRow)
Me.grid.ExpandGroupRow(groupRow)
childRow = Me.grid.FindRowByValue(Me.grid.Columns(NameOf(Invoice.Status)), InvoiceStatus.Delivered)
groupRow = Me.grid.GetParentRowHandle(childRow)
Me.grid.CollapseGroupRow(groupRow)
End If
End Sub
Private Sub OnGroupRowCollapsing(ByVal sender As Object, ByVal e As RowAllowEventArgs)
If e.Row IsNot Nothing AndAlso Me.grid.GetGroupRowValue(e.RowHandle).Equals(InvoiceStatus.Invalidated) Then e.Allow = False
End Sub
Private Sub OnGroupRowCollapsed(ByVal sender As Object, ByVal e As RowEventArgs)
If e.Row Is Nothing AndAlso Me.grid.Columns(NameOf(Invoice.Status)).GroupIndex = 0 Then
Dim childRow = Me.grid.FindRowByValue(Me.grid.Columns(NameOf(Invoice.Status)), InvoiceStatus.Invalidated)
Dim groupRow = Me.grid.GetParentRowHandle(childRow)
Me.grid.ExpandGroupRow(groupRow)
End If
End Sub
Private Sub OnGroupRowExpanding(ByVal sender As Object, ByVal e As RowAllowEventArgs)
If e.Row IsNot Nothing AndAlso Me.grid.GetGroupRowValue(e.RowHandle).Equals(InvoiceStatus.Delivered) Then e.Allow = False
End Sub
Private Sub OnGroupRowExpanded(ByVal sender As Object, ByVal e As RowEventArgs)
If e.Row Is Nothing AndAlso Me.grid.Columns(NameOf(Invoice.Status)).GroupIndex = 0 Then
Dim childRow = Me.grid.FindRowByValue(Me.grid.Columns(NameOf(Invoice.Status)), InvoiceStatus.Delivered)
Dim groupRow = Me.grid.GetParentRowHandle(childRow)
Me.grid.CollapseGroupRow(groupRow)
End If
End Sub