ICommandHandler Interface

If implemented by a class, provides methods for handling commands in an End-User Designer for Windows Forms.

Namespace: DevExpress.XtraReports.UserDesigner

Assembly: DevExpress.XtraReports.v20.2.Extensions.dll

NuGet Package: DevExpress.Win.Reporting

Declaration

C#

public interface ICommandHandler

VB.NET

Public Interface ICommandHandler

Remarks

An object implementing the ICommandHandler interface is passed to the XRDesignPanel.AddCommandHandler and XRDesignMdiController.AddCommandHandler methods as a parameter.

Every report command represents either a toolbar button and a menu item, or a context menu item, or a context link in the End-User Designer window.

To learn more, see ICommandHandler.CanHandleCommand and ICommandHandler.HandleCommand.

Example

This example demonstrates how you can prohibit your end-users from deleting a control in the End-User Designer.

Form1.cs

using System;
using System.Windows.Forms;
using DevExpress.XtraReports.UI;
using DevExpress.XtraReports.UserDesigner;
// ...

namespace PreventDeletingControl {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e) {
            this.xrDesignPanel1.AddCommandHandler(new DeleteCommandHandler(this.xrDesignPanel1));
            // Load a report into the design form and show the form.
            this.xrDesignPanel1.OpenReport(new XtraReport1());
        }
    }
}

public class DeleteCommandHandler : ICommandHandler {
    XRDesignPanel panel;

    public DeleteCommandHandler(XRDesignPanel panel) {
        this.panel = panel;
    }

    public bool CanHandleCommand(ReportCommand command, ref bool useNextHandler) {
        useNextHandler = command != ReportCommand.Delete && !IsXRLabelSelected();
        return !useNextHandler;
    }

    public void HandleCommand(ReportCommand command, object[] args) {
        MessageBox.Show("Cannot delete label!");
    }

    Boolean IsXRLabelSelected() {
        object[] controls = panel.GetSelectedComponents();

        foreach (object obj in controls)
            if (obj is XRLabel)
                return true;

        return false;
    }
}

Form1.vb

Imports Microsoft.VisualBasic
Imports System
Imports System.Windows.Forms
Imports DevExpress.XtraReports.UI
Imports DevExpress.XtraReports.UserDesigner
' ...

Namespace PreventDeletingControl
    Partial Public Class Form1
        Inherits Form
        Public Sub New()
            InitializeComponent()
        End Sub

        Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
            Me.xrDesignPanel1.AddCommandHandler(New DeleteCommandHandler(Me.xrDesignPanel1))
            ' Load a report into the design form and show the form.
            Me.xrDesignPanel1.OpenReport(New XtraReport1())
        End Sub
    End Class
End Namespace

Public Class DeleteCommandHandler
    Implements ICommandHandler
    Private panel As XRDesignPanel

    Public Sub New(ByVal panel As XRDesignPanel)
        Me.panel = panel
    End Sub

    Public Function CanHandleCommand(ByVal command As ReportCommand, _
        ByRef useNextHandler As Boolean) As Boolean Implements ICommandHandler.CanHandleCommand
        useNextHandler = command <> ReportCommand.Delete AndAlso Not IsXRLabelSelected()
        Return Not useNextHandler
    End Function

    Public Sub HandleCommand(ByVal command As ReportCommand, _
        ByVal args() As Object) Implements ICommandHandler.HandleCommand
        MessageBox.Show("Cannot delete label!")
    End Sub

    Private Function IsXRLabelSelected() As Boolean
        Dim controls() As Object = panel.GetSelectedComponents()

        For Each obj As Object In controls
            If TypeOf obj Is XRLabel Then
                Return True
            End If
        Next obj

        Return False
    End Function
End Class