Ways to Show a Confirmation Dialog

• Mar 12, 2021
• 6 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 and Mobile 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#

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

VB.NET

Public Class ConfirmationWindowActionController
    Inherits ViewController
    Private deleteObjectsViewController As DeleteObjectsViewController
    Protected Overrides Sub OnActivated()
        MyBase.OnActivated()
        deleteObjectsViewController = Frame.GetController(Of DeleteObjectsViewController)()
        If deleteObjectsViewController IsNot Nothing Then
            AddHandler View.SelectionChanged, AddressOf View_SelectionChanged
        End If
    End Sub
    Private Sub View_SelectionChanged(ByVal sender As Object, ByVal e As System.EventArgs)
        deleteObjectsViewController.DeleteAction.ConfirmationMessage = _
String.Format("You are about to delete {0} object(s). Do you want to proceed?", (View.SelectedObjects.Count))
    End Sub
    Protected Overrides Sub OnDeactivated()
        MyBase.OnDeactivated()
        If deleteObjectsViewController IsNot Nothing Then
            RemoveHandler View.SelectionChanged, AddressOf View_SelectionChanged
            deleteObjectsViewController = Nothing
        End If
    End Sub
End Class

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 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; }
}

VB.NET

Imports DevExpress.ExpressApp.DC
Imports DevExpress.ExpressApp.Model
'...
<DomainComponent> 
Public Class ConfirmationWindowParameters
    Public Sub New()
    End Sub
    <ModelDefault("AllowEdit", "False")>
    Public Property ConfirmationMessage() As String
End Class

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 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;
    }
}

VB.NET

Imports DevExpress.ExpressApp
Imports DevExpress.ExpressApp.Actions
'...
Public Class ConfirmationWindowController
    Inherits ViewController
    Public Sub New()
        Dim showConfirmationWindowAction As New PopupWindowShowAction(Me, "CustomConfirmationWindow", DevExpress.Persistent.Base.PredefinedCategory.View)
        showConfirmationWindowAction.ImageName = "ModelEditor_Views"
        AddHandler showConfirmationWindowAction.CustomizePopupWindowParams, AddressOf showConfirmationWindowAction_CustomizePopupWindowParams
    End Sub
    Private Sub showConfirmationWindowAction_CustomizePopupWindowParams(ByVal sender As Object, ByVal e As CustomizePopupWindowParamsEventArgs)
        Dim objectSpace As NonPersistentObjectSpace = _
        CType(Application.CreateObjectSpace(GetType(ConfirmationWindowParameters)), NonPersistentObjectSpace)
        Dim parameters As ConfirmationWindowParameters = objectSpace.CreateObject(Of ConfirmationWindowParameters)()
        parameters.ConfirmationMessage = "Confirmation message text."
        objectSpace.CommitChanges()
        Dim confirmationDetailView As DetailView = Application.CreateDetailView(objectSpace, parameters)
        confirmationDetailView.Caption = "Custom Confirmation Window"
        confirmationDetailView.ViewEditMode = DevExpress.ExpressApp.Editors.ViewEditMode.View
        e.View = confirmationDetailView
    End Sub
End Class

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!");
    }
}

VB.NET

Imports DevExpress.ExpressApp
Imports DevExpress.ExpressApp.Actions
Imports DevExpress.Persistent.Base
' ...
Public Class ConfirmationWindowController
    Inherits ViewController
    Public Sub New()
        Dim showConfirmationWindowAction As New SimpleAction(Me, "CustomConfirmationWindow", _
        PredefinedCategory.View)
        showConfirmationWindowAction.ImageName = "ModelEditor_Views"
        AddHandler showConfirmationWindowAction.Execute, _
        AddressOf ShowConfirmationWindowAction_Execute
    End Sub
    Private Sub ShowConfirmationWindowAction_Execute(ByVal sender As Object, _
    ByVal e As SimpleActionExecuteEventArgs)
        Dim objectSpace As NonPersistentObjectSpace = _
        CType(Application.CreateObjectSpace(GetType(ConfirmationWindowParameters)), NonPersistentObjectSpace)
        Dim parameters As New ConfirmationWindowParameters()
        parameters.ConfirmationMessage = "A confirmation message text."
        Dim confirmationDetailView As DetailView = _
        Application.CreateDetailView(objectSpace, parameters)
        confirmationDetailView.Caption = "Custom Confirmation Window"
        Application.ShowViewStrategy.ShowViewInPopupWindow(confirmationDetailView, _
        AddressOf OkDelegate, AddressOf CancelDelegate)
    End Sub
    Public Sub OkDelegate()
            Application.ShowViewStrategy.ShowMessage("The message is accepted!")
    End Sub
    Public Sub CancelDelegate()
            Application.ShowViewStrategy.ShowMessage("The message is canceled!")
    End Sub
End Class

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();
    }
}

VB.NET

Public Class MessagingController
    Inherits ViewController
    Public Sub New()
        Dim showMessagingConfirmationForm As New SimpleAction(Me, "CustomDeleteAction", DevExpress.Persistent.Base.PredefinedCategory.View)
        showMessagingConfirmationForm.ImageName = "Action_Delete"
        AddHandler showMessagingConfirmationForm.Execute, _
AddressOf showMessagingConfirmationForm_Execute
    End Sub
    Private Sub showMessagingConfirmationForm_Execute(ByVal sender As Object, _
ByVal e As SimpleActionExecuteEventArgs)
        If WinApplication.Messaging.GetUserChoice("Do you want to delete the selected object(s)?", _
"Confirmation Window", MessageBoxButtons.YesNo) = DialogResult.Yes Then
            View.ObjectSpace.Delete(e.SelectedObjects)
        End If
        View.ObjectSpace.CommitChanges()
    End Sub
End Class

The image below demonstrates this implementation result.