How to: Replace Built-In Command with a Custom Command

• Apr 01, 2021
• 3 minutes to read

This topic describes how to use the service substitution technique to replace the built-in SpreadsheetControl command with a custom command.

View Example

The SpreadsheetControl uses the command factory service to create its commands. You can substitute the default command factory service with its descendant to create a custom command.

Follow the steps below to create and register a custom command.

1. Create a custom command class inherited from the command you want to replace. Override the ExecuteCore method to specify actions that the new command should perform.

   The example below shows how to customize the standard DevExpress.XtraSpreadsheet.Commands.FormatClearContentsCommand command.

   C#

   public class CustomFormatClearContentsCommand : DevExpress.XtraSpreadsheet.Commands.FormatClearContentsCommand
   {
       public CustomFormatClearContentsCommand(ISpreadsheetControl control)
           : base(control)
       {
       }
   
       protected override void ExecuteCore()
       {
           // Display a confirmation dialog before removing the cell's content. 
           MessageBoxResult result = DXMessageBox.Show("Do you want to clear the cell content?", "Warning", MessageBoxButton.YesNo, MessageBoxImage.Warning);
           if (result == MessageBoxResult.Yes)
               base.ExecuteCore();
       }
   }
   

   VB.NET

   Public Class CustomFormatClearContentsCommand
       Inherits DevExpress.XtraSpreadsheet.Commands.FormatClearContentsCommand
   
       Public Sub New(ByVal control As ISpreadsheetControl)
           MyBase.New(control)
       End Sub
   
       Protected Overrides Sub ExecuteCore()
           'Display a confirmation dialog before removing the cell's content.
           Dim result As MessageBoxResult = DXMessageBox.Show("Do you want to clear the cell content?", "Warning", MessageBoxButton.YesNo, MessageBoxImage.Warning)
           If result = MessageBoxResult.Yes Then
               MyBase.ExecuteCore()
           End If
       End Sub
   End Class
   

2. Create a class inherited from SpreadsheetCommandFactoryServiceWrapper to replace the default command service. In this class, override the SpreadsheetCommandFactoryServiceWrapper.CreateCommand method to replace the default FormatClearContents and FormatClearContentsContextMenuItem commands with the custom command.

   C#

   public class CustomService : SpreadsheetCommandFactoryServiceWrapper
   {
       public CustomService(ISpreadsheetCommandFactoryService service)
           : base(service)
       {
       }
       public SpreadsheetControl Control { get; set; }
   
       public override SpreadsheetCommand CreateCommand(SpreadsheetCommandId id)
       {
           if (id == SpreadsheetCommandId.FormatClearContents || id == SpreadsheetCommandId.FormatClearContentsContextMenuItem)
               return new CustomFormatClearContentsCommand(Control);
           return base.CreateCommand(id);
       }
   }
   

   VB.NET

   Public Class CustomService
       Inherits SpreadsheetCommandFactoryServiceWrapper
   
       Public Sub New(ByVal service As ISpreadsheetCommandFactoryService)
            MyBase.New(service)
       End Sub
       Public Property Control() As SpreadsheetControl
   
       Public Overrides Function CreateCommand(ByVal id As SpreadsheetCommandId) As SpreadsheetCommand
           If id = SpreadsheetCommandId.FormatClearContents OrElse id = SpreadsheetCommandId.FormatClearContentsContextMenuItem Then
               Return New CustomFormatClearContentsCommand(Control)
           End If
           Return MyBase.CreateCommand(id)
       End Function
   End Class
   

3. Create a CustomService instance and use the SpreadsheetControl.ReplaceService<T> method to replace the default service with the custom service. Note that due to WPF Spreadsheet implementation specifics, it is necessary to replace the built-in service after the control is loaded.

   C#

   void spreadsheetControl_Loaded(object sender, System.Windows.RoutedEventArgs e)
   {
       Dispatcher.BeginInvoke(new Action(() => {
           SubstituteService();
       }), System.Windows.Threading.DispatcherPriority.Render);
   }
   
   private void SubstituteService()
   {
       ISpreadsheetCommandFactoryService service = (ISpreadsheetCommandFactoryService)spreadsheetControl.GetService(typeof(ISpreadsheetCommandFactoryService));
       CustomService customService = new CustomService(service);
       spreadsheetControl.ReplaceService<ISpreadsheetCommandFactoryService>(customService);
       customService.Control = spreadsheetControl;
   }
   

   VB.NET

   Private Sub spreadsheetControl_Loaded(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs)
       Dispatcher.BeginInvoke(New Action(Sub()
           SubstituteService()
       End Sub), System.Windows.Threading.DispatcherPriority.Render)
   End Sub
   
   Private Sub SubstituteService()
       Dim service As ISpreadsheetCommandFactoryService = DirectCast(spreadsheetControl.GetService(GetType(ISpreadsheetCommandFactoryService)), ISpreadsheetCommandFactoryService)
       Dim customService As New CustomService(service)
       spreadsheetControl.ReplaceService(Of ISpreadsheetCommandFactoryService)(customService)
       customService.Control = spreadsheetControl
   End Sub
   

Run the application. Select any cell and press DELETE, or click Clear Contents on the ribbon or in the context menu. The SpreadsheetControl displays the message “Do you want to clear the cell content?”. Click Yes to clear the cell, or select No to cancel the operation.