TreeListView.CellEditorValueChangingCommand Property

Gets or sets a command executed when a user edits a cell editor value (for example, types or deletes a character, chooses a value from the drop-down list, etc.).

Namespace: DevExpress.Xpf.Grid

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

Declaration

C#

public ICommand<CellEditorValueChangingArgs> CellEditorValueChangingCommand { get; set; }

VB.NET

Public Property CellEditorValueChangingCommand As ICommand(Of CellEditorValueChangingArgs)

Property Value

Type	Description
ICommand<CellEditorValueChangingArgs>	A command executed when a user edits a cell value (for example, types or deletes a character, chooses a value from the drop-down list, etc.).

Remarks

The TreeListControl does not execute a command bound to CellValueChangingCommand when you change a cell editor value in code.

To restore the previous cell editor value (and prevent the CellValueChanging event from occurring), set the Cancel property to true.

Example

The following example prompts the user before changing a cell value. If the user cancels the action, the cell value remains unchanged:

<dx:ThemedWindow ...
    xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
    xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid"
    xmlns:dxmvvm="http://schemas.devexpress.com/winfx/2008/xaml/mvvm">

    <dxmvvm:Interaction.Behaviors>
        <dx:DXMessageBoxService/>
    </dxmvvm:Interaction.Behaviors>

    <Grid>
        <dxg:TreeListControl ItemsSource="{Binding DataItems}">
            <dxg:TreeListControl.Columns>
                <dxg:TreeListColumn FieldName="Name"/>
                <dxg:TreeListColumn FieldName="Executor"/>
                <dxg:TreeListColumn FieldName="State"/>
            </dxg:TreeListControl.Columns>
            <dxg:TreeListControl.View>
                <dxg:TreeListView  
                    TreeDerivationMode="ChildNodesSelector" 
                    ChildNodesPath="Tasks"
                    CellEditorValueChangingCommand="{Binding StateChangingCommand}"/>
            </dxg:TreeListControl.View>
        </dxg:TreeListControl>
    </Grid>
</dx:ThemedWindow>

public class ViewModel : ViewModelBase {

    IMessageBoxService MessageBoxService { get { return GetService<IMessageBoxService>(); } }

    [Command]
    public void StateChanging(CellEditorValueChangingArgs args) {
        if(args.FieldName == nameof(DataItem.State)) {
            MessageResult result;
            result = MessageBoxService.ShowMessage(
                messageBoxText: "Changing the cell value will start time consuming calculations. Do you want to continue?",
                caption: "Warning",
                icon: MessageIcon.Warning,
                button: MessageButton.OKCancel,
                defaultResult: MessageResult.OK
            );
            switch(result) {
                case MessageResult.OK:
                    args.Cancel = false;
                    break;
                case MessageResult.Cancel:
                    args.Cancel = true;
                    break;
            }
        }
    }
}