DataViewBase.ColumnDragOver Event

Occurs when a user drags a column or band over a drop target.

Namespace: DevExpress.Xpf.Grid

Assembly: DevExpress.Xpf.Grid.v26.1.Core.dll

Declaration

C#

public event ColumnDragOverEventHandler ColumnDragOver

VB.NET

Public Event ColumnDragOver As ColumnDragOverEventHandler

Event Data

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

Property	Description
Cancel	Gets or sets whether the event should be canceled. Inherited from CancelRoutedEventArgs.
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.
Source	Gets or sets a reference to the object that raised the event. Inherited from RoutedEventArgs.
SourceArea	Gets the source area where the drag operation started.
SourceBand	Gets the source band where the drag operation started.
SourceBandIndex	Gets the index of the source band where the drag operation started.
SourceBandRowIndex	Gets the row index of the source band where the drag operation started.
SourceColumn	Gets the source column or band where the drag operation started.
SourceIndex	Gets the index of the source column or band where the drag operation started.
SourceView	Gets the source view where the drag operation started.
TargetArea	Gets the target area where the dragged item is about to be dropped.
TargetBand	Gets the target band where the dragged item is about to be dropped.
TargetBandIndex	Gets the index of the target band where the dragged item is about to be dropped.
TargetBandRowIndex	Gets the row index of the target band where the dragged item is about to be dropped.
TargetColumn	Gets the target column or band where the dragged item is about to be dropped.
TargetIndex	Gets the index of the target column or band where the dragged item is about to be dropped.

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

Handle the ColumnDragOver event to modify predefined behavior for column and band drag & drop operations. The ColumnDragOverEventArgs class includes parameters that allow you to modify drag & drop functionality within a ColumnDragOver event handler.

XAML

<ThemedWindow ...
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid" >

    <dxg:GridControl ItemsSource="{Binding Items}">
        <dxg:GridControl.Columns>
            <dxg:GridColumn FieldName="ID" />
            <dxg:GridColumn FieldName="Name" />
            <dxg:GridColumn FieldName="Date" />
        </dxg:GridControl.Columns>
        <dxg:GridControl.View>
            <dxg:TableView ColumnDragOver="TableView_ColumnDragOver" />
        </dxg:GridControl.View>
    </dxg:GridControl>
</ThemedWindow>

C#

private void TableView_ColumnDragOver(object sender, ColumnDragOverEventArgs e) {
    if (e.TargetArea == HeaderArea.ColumnHeader) {
        e.Cancel = true;
    }
}