PropertyGridControl.CollectionButtonsVisibility Event

Allows you to show and hide collection buttons (Add Item and Remove Item) based on custom logic.

Namespace: DevExpress.Xpf.PropertyGrid

Assembly: DevExpress.Xpf.PropertyGrid.v23.2.dll

NuGet Package: DevExpress.Wpf.PropertyGrid

Declaration

C#

public event EventHandler<CollectionButtonsVisibilityEventArgs> CollectionButtonsVisibility

VB.NET

Public Event CollectionButtonsVisibility As EventHandler(Of CollectionButtonsVisibilityEventArgs)

Event Data

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

Property	Description
ButtonKind	Gets the collection button‘s type. Inherited from CollectionButtonBaseEventArgs.
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.
IsVisible	Gets or sets whether to display the collection button.
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 a property grid row. Inherited from PropertyGridRowBaseEventArgs.
Source	Gets or sets a reference to the object that raised the event. Inherited from RoutedEventArgs.
Value	Gets a row’s value. Inherited from PropertyGridRowBaseEventArgs.

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

View Example: Specify Custom Collection Edit Actions

Handle the CollectionButtonsVisibility event to implement custom logic that shows and hides collection buttons. The following code sample hides the Add Item button if the collection contains more than 5 items and hides the Remove Item button for the collection item whose ID is 0:

XAML

<dxprg:PropertyGridControl SelectedObject="{Binding DemoProduct}" 
                           CollectionButtonsVisibility="OnCollectionButtonsVisibility"/>

C#

using DevExpress.Xpf.PropertyGrid;
// ...

void OnCollectionButtonsVisibility(object sender, CollectionButtonsVisibilityEventArgs e) {
    if (e.ButtonKind == CollectionButtonKind.Add) {
        var collection = (SupplierList)e.Value;
        e.IsVisible = collection.Count <= 5;
    }
    if (e.ButtonKind == CollectionButtonKind.Remove) { 
        var supplier = e.Value as Supplier;
        if (supplier != null && supplier.ID == 0)
            e.IsVisible = false;
    }
}

VB.NET

Imports DevExpress.Xpf.PropertyGrid
' ...

Private Sub OnCollectionButtonsVisibility(ByVal sender As Object, ByVal e As CollectionButtonsVisibilityEventArgs)
    If e.ButtonKind = CollectionButtonKind.Add Then
        Dim collection = CType(e.Value, SupplierList)
        e.IsVisible = collection.Count <= 5
    End If

    If e.ButtonKind = CollectionButtonKind.Remove Then
        Dim supplier = TryCast(e.Value, Supplier)
        If supplier IsNot Nothing AndAlso supplier.ID = 0 Then e.IsVisible = False
    End If
End Sub

Refer to the following help topic for more information: Collection Definitions.