Invoke Custom Command From Grid Button

[Geoff]

Hello,

I have a grid with a custom edit command and a template column with a button. I'm attempting to invoke the custom edit command from clicking the button, but the parameter object passed to the Execute method is null. This object is instantiated when using the built-in edit functionality through double-clicking on the row or pressing F2 on the keyboard, but not when the edit button is clicked.

How can I pass the EditContext parameter to my custom command from this button? Please note that I am working with the MVVM Light toolkit.

<RadGrid:RadDataGrid    Name="rdgPlay"
    Grid.Row="0"
    ItemsSource="{Binding Plays}"
    DataBindingComplete="rdgPlay_DataBindingComplete"
    UserSortMode="None"
    UserFilterMode="Disabled"
    UserGroupMode="Disabled"
    UserEditMode="Inline"
    SelectionMode="None">
    <RadGrid:RadDataGrid.Columns>
         <RadGrid:DataGridTemplateColumn CanUserEdit="False">
            <RadGrid:DataGridTemplateColumn.CellContentTemplate>
                <DataTemplate>
                    <StackPanel>
                         <Button Content="Edit">
                            <Button.Command>
                                <CustomCommands:CustomBeginEditCommand />
                            </Button.Command>
                        </Button>
                    </StackPanel>
                </DataTemplate>
            </RadGrid:DataGridTemplateColumn.CellContentTemplate>
        </RadGrid:DataGridTemplateColumn>
    </RadGrid:RadDataGrid.Columns>
    <RadGrid:RadDataGrid.Commands>
        <CustomCommands:CustomBeginEditCommand />
    </RadGrid:RadDataGrid.Commands>
</RadGrid:RadDataGrid>

public class CustomBeginEditCommand : DataGridCommand

{

  public CustomBeginEditCommand()

  {

     // Set Id so that this command can be properly associated with the desired action/event

     Id = CommandId.BeginEdit;

  }

 

  public override bool CanExecute(object parameter)

  {

    return true;

  }

 

  public override void Execute(object parameter)

  {

    base.Execute(parameter);

 

    var context = parameter as EditContext; // parameter is sometimes null


 

    // Executes the default implementation of this command

    this.Owner.CommandService.ExecuteDefaultCommand(Id, context);

  }

}

Thanks!
Geoff

[Ivaylo Gergov]

Hello Geoff,

Thank you for contacting us and for your question.

In this case, you execute the BeginEditCommand programmatically and you should pass the parameter. Thus, the RadDataGrid will know which row to edit. As the Button.CommandParameter does not support binding, I can suggest that you implement an attached behavior that will pass the desired EditContext  as CommandParameter. To build the EditContext you will need only the DataGridCellInfo object (the business item and the column).
You can also check the following forum post where I have showed an example of how to implement an attached behavior - http://www.telerik.com/community/forums/windows8-xaml/grid-xaml/synchronizing-selecteditems-between-a-raddatagrid-and-a-viewmodel.aspx

I hope this helps. Let me know if I can assist you in some other way.

Regards,
Ivaylo Gergov
Telerik