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GridControl.GroupRowExpanded Event

wpf-devexpress-dot-xpf-dot-grid-dot-gridcontrol-f844745b.md

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GridControl.GroupRowExpanded Event

Occurs after a group row has been expanded.

Namespace : DevExpress.Xpf.Grid

Assembly : DevExpress.Xpf.Grid.v25.2.dll

NuGet Package : DevExpress.Wpf.Grid.Core

Declaration

csharp
public event RowEventHandler GroupRowExpanded
vb
Public Event GroupRowExpanded As RowEventHandler

Event Data

The GroupRowExpanded event's data class is RowEventArgs. The following properties provide information specific to this event:

PropertyDescription
HandledGets or sets a value that indicates the present state of the event handling for a routed event as it travels the route. Inherited from RoutedEventArgs.
OriginalSourceGets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class. Inherited from RoutedEventArgs.
RoutedEventGets or sets the RoutedEvent associated with this RoutedEventArgs instance. Inherited from RoutedEventArgs.
RowGets the processed row.
RowHandleGets the processed row’s handle.
SourceGets the View that raised the event.

The event data class exposes the following methods:

MethodDescription
InvokeEventHandler(Delegate, Object)When overridden in a derived class, provides a way to invoke event handlers in a type-specific way, which can increase efficiency over the base implementation. Inherited from RoutedEventArgs.
OnSetSource(Object)When overridden in a derived class, provides a notification callback entry point whenever the value of the Source property of an instance changes. Inherited from RoutedEventArgs.

Remarks

The GroupRowExpanded event is raised after a group row has been expanded by an end-user or in code. The group row is identified by its handle via the RowEventArgs.RowHandle property. This event serves as a notification, and the action cannot be cancelled. To control whether individual group rows can be expanded, handle the GridControl.GroupRowExpanding event.

Group rows can be expanded recursively using the GridViewBase.ExpandFocusedRow method overload with the recursive parameter set to true. In this instance, the GroupRowExpanded event is raised only once (for the row passed as this method’s parameter). This event isn’t raised for nesting group rows.

The GridControl.ExpandAllGroups method allows you to expand all group rows. In this instance, the GroupRowExpanded event is raised only once. The event parameter’s RowEventArgs.RowHandle property returns an invalid row handle (DataControlBase.InvalidRowHandle).

To learn more, see Expanding and Collapsing Group Rows.

Example

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

xaml
<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>
cs
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);
    }
}
vb
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

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the GroupRowExpanded event.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

wpf-grid-prevent-expand-collapse-operations-for-group-rows/CS/Forbid_Expand_Collapse/MainWindow.xaml#L23

xml
GroupRowExpanding="OnGroupRowExpanding"
             GroupRowExpanded="OnGroupRowExpanded">
<dxg:GridColumn FieldName="ProductName"/>

wpf-grid-prevent-expand-collapse-operations-for-group-rows/VB/Forbid_Expand_Collapse/obj.NetFX/Debug/MainWindow.g.vb#L124

vb
#ExternalSource("..\..\MainWindow.xaml",23)
AddHandler Me.grid.GroupRowExpanded, New DevExpress.Xpf.Grid.RowEventHandler(AddressOf Me.OnGroupRowExpanded)

See Also

GroupRowExpanding

GroupRowCollapsing

GroupRowCollapsed

GridControl Class

GridControl Members

DevExpress.Xpf.Grid Namespace