Ways to Show a Confirmation Dialog

• Oct 11, 2024
• 4 minutes to read

This topic describes how to show a confirmation message/dialog with additional fields.

This topic consists of the following sections:

• Platform-independent approaches:
  • Using the ConfirmationMessage Property
  • Using a New Detail View
• A WinForms-specific approach:
  • Using a Messaging Class’ Methods

Tip

Refer to the following topics if you want to show a text notification:

• Text Notifications
• Error Handling in ASP.NET Web Forms Applications

Using the ConfirmationMessage Property

Use the ActionBase.ConfirmationMessage property in code or IModelAction.ConfirmationMessage in the Model Editor to change a default confirmation message for built-in or custom Actions.

For example, implement the following Controller to change the Delete Action’s confirmation message:

C#

using DevExpress.ExpressApp.SystemModule;
using DevExpress.ExpressApp;
using System;

namespace MySolutionName.Module.Controllers {
    public class ConfirmationWindowActionController : ViewController {
        DeleteObjectsViewController deleteObjectsViewController;
        protected override void OnActivated() {
            base.OnActivated();
            deleteObjectsViewController = Frame.GetController<DeleteObjectsViewController>();
            if (deleteObjectsViewController != null) {
                View.SelectionChanged += View_SelectionChanged;
                SetConfirmationMessage();
            }
        }
        void View_SelectionChanged(object sender, EventArgs e) {
            SetConfirmationMessage();
        }

        private void SetConfirmationMessage() {
            deleteObjectsViewController.DeleteAction.ConfirmationMessage = String.Format("You are about to delete {0} object(s). Do you want to proceed?", View.SelectedObjects.Count);
        }

        protected override void OnDeactivated() {
            base.OnDeactivated();
            if (deleteObjectsViewController != null) {
                View.SelectionChanged -= View_SelectionChanged;
                deleteObjectsViewController = null;
            }
        }
    }
}

Click the Delete Action to see the result:

Using a New Detail View

This section demonstrates how to invoke pop-up window with a non-persistent object’s Detail View.

Add the following non-persistent class to your platform-agnostic MySolution.Module project. Decorate this class with the DomainComponentAttribute to register it in the Types Info Subsystem.

C#

using DevExpress.ExpressApp.DC;
using DevExpress.ExpressApp.Model;
//...
[DomainComponent]
public class ConfirmationWindowParameters {
    public ConfirmationWindowParameters() { }
    [ModelDefault("AllowEdit", "False")]
    public string ConfirmationMessage { get; set; }
}

Use one of the following approaches to show the confirmation message in a pop-up window when an Action is executed:

• using the CustomizePopupWindowParams event;
• using the ShowViewInPopupWindow method (WinForms and ASP.NET Web Forms only).

Using the CustomizePopupWindowParams event

1. Create a new ViewController and PopupWindowShowAction in its constructor.
2. In the Action’s CustomizePopupWindowParams event, create a non-persistent Object Space, a new ConfirmationWindowParameters class instance, and the DetailView for this object.
3. Specify the ConfirmationWindowParameters object’s properties and set the CustomizePopupWindowParamsEventArgs.View parameter to the newly created Detail View to show it in the pop-up window.

C#

using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Actions;
//...
public class ConfirmationWindowController : ViewController {
    public ConfirmationWindowController() {
        PopupWindowShowAction showConfirmationWindowAction = 
new PopupWindowShowAction(this, "CustomConfirmationWindow", DevExpress.Persistent.Base.PredefinedCategory.View);
        showConfirmationWindowAction.ImageName = "ModelEditor_Views";
        showConfirmationWindowAction.CustomizePopupWindowParams += 
showConfirmationWindowAction_CustomizePopupWindowParams;
    }
    private void showConfirmationWindowAction_CustomizePopupWindowParams(object sender, 
CustomizePopupWindowParamsEventArgs e) {
        NonPersistentObjectSpace objectSpace = 
        (NonPersistentObjectSpace)Application.CreateObjectSpace(typeof(ConfirmationWindowParameters));
        ConfirmationWindowParameters parameters = 
        objectSpace.CreateObject<ConfirmationWindowParameters>();
        parameters.ConfirmationMessage = "Confirmation message text.";
        objectSpace.CommitChanges();
        DetailView confirmationDetailView = Application.CreateDetailView(objectSpace, parameters);
        confirmationDetailView.Caption = "Custom Confirmation Window";
        confirmationDetailView.ViewEditMode = DevExpress.ExpressApp.Editors.ViewEditMode.View;
        e.View = confirmationDetailView;
    }
}

The following images demonstrate this confirmation window:

Note

You can also process the OK and Close button clicks. For this purpose, use the CustomizePopupWindowParamsEventArgs.DialogController property to access the Dialog Controller, and subscribe to its Accepting and Canceling events.

Using the ShowViewInPopupWindow method

1. Create a new ViewController and SimpleAction in its constructor.
2. In the Action’s Execute event, create a non-persistent Object Space, a new ConfirmationWindowParameters class instance, and the DetailView for this object.
3. Set the ConfirmationWindowParameters object’s properties to the required values and call the ShowViewStrategyBase.ShowViewInPopupWindow method. Pass the newly created Detail View as the ShowViewInPopupWindow‘s first parameter to show this View in a pop-up. You can also pass delegates for processing the Ok and Cancel buttons click.

C#

using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Actions;
using DevExpress.Persistent.Base;
// ...
public class ConfirmationWindowController : ViewController {
    public ConfirmationWindowController() {
        SimpleAction showConfirmationWindowAction = new SimpleAction(this, "CustomConfirmationWindow", PredefinedCategory.View);
        showConfirmationWindowAction.ImageName = "ModelEditor_Views";
        showConfirmationWindowAction.Execute += ShowConfirmationWindowAction_Execute;
    }
    private void ShowConfirmationWindowAction_Execute(object sender, 
    SimpleActionExecuteEventArgs e) {
        NonPersistentObjectSpace objectSpace = 
        (NonPersistentObjectSpace)Application.CreateObjectSpace(typeof(ConfirmationWindowParameters));
        ConfirmationWindowParameters parameters = new ConfirmationWindowParameters();
        parameters.ConfirmationMessage = "A confirmation message text.";
        DetailView confirmationDetailView = Application.CreateDetailView(objectSpace, parameters);
        confirmationDetailView.Caption = "Custom Confirmation Window";
        Application.ShowViewStrategy.ShowViewInPopupWindow(confirmationDetailView, OkDelegate, CancelDelegate);
    }
    public void OkDelegate() {
            Application.ShowViewStrategy.ShowMessage("The message is accepted!");
    }
    public void CancelDelegate() {
            Application.ShowViewStrategy.ShowMessage("The message is canceled!");
    }
}

Using the Messaging Class’ Methods

Use the Messaging class’s methods to display a confirmation message with standard dialog buttons (see MessageBoxButtons) in WinForms applications. The following Controller demonstrates how to use this class to show a confirmation window:

C#

public class MessagingController : ViewController {
    public MessagingController() {
        SimpleAction showMessagingConfirmationForm = new SimpleAction(this, "CustomDeleteAction", DevExpress.Persistent.Base.PredefinedCategory.View);
        showMessagingConfirmationForm.ImageName = "Action_Delete";
        showMessagingConfirmationForm.Execute += showMessagingConfirmationForm_Execute;
    }
    void showMessagingConfirmationForm_Execute(object sender, SimpleActionExecuteEventArgs e) {
        if (WinApplication.Messaging.GetUserChoice("Do you want to delete the selected object(s)?", 
"Confirmation Window", MessageBoxButtons.YesNo) == DialogResult.Yes)
            View.ObjectSpace.Delete(e.SelectedObjects);
        View.ObjectSpace.CommitChanges();
    }
}

The image below demonstrates this implementation result.