GridControl.GroupRowCollapsed Event

Occurs after a group row has been collapsed.

Namespace: DevExpress.Xpf.Grid

Assembly: DevExpress.Xpf.Grid.v24.2.dll

NuGet Package: DevExpress.Wpf.Grid.Core

Declaration

C#

public event RowEventHandler GroupRowCollapsed

VB.NET

Public Event GroupRowCollapsed As RowEventHandler

Event Data

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

Property	Description
Handled	Gets 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.
OriginalSource	Gets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class. Inherited from RoutedEventArgs.
RoutedEvent	Gets or sets the RoutedEvent associated with this RoutedEventArgs instance. Inherited from RoutedEventArgs.
Row	Gets the processed row.
RowHandle	Gets the processed row’s handle.
Source	Gets the View that raised the event.

The event data class exposes the following methods:

Method	Description
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 GroupRowCollapsed event is raised after a group row has been collapsed 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 collapsed, handle the GridControl.GroupRowCollapsing event.

Group rows can be collapsed recursively using the GridViewBase.CollapseFocusedRow method overload with the recursive parameter set to true. In this instance, the GroupRowCollapsed 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.CollapseAllGroups method allows you to collapse all group rows. In this instance, the GroupRowCollapsed 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>

C#

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.NET

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

Related GitHub Examples

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

XAML

wpf-grid-prevent-expand-collapse-operations-for-group-rows/CS/Forbid_Expand_Collapse/MainWindow.xaml#L21

GroupRowCollapsing="OnGroupRowCollapsing"
GroupRowCollapsed="OnGroupRowCollapsed"
GroupRowExpanding="OnGroupRowExpanding"