ViewController.TargetObjectType Property

Specifies a ViewController‘s target object type. The View Controller is activated only for Views that represent this type.

Namespace: DevExpress.ExpressApp

Assembly: DevExpress.ExpressApp.v24.2.dll

NuGet Package: DevExpress.ExpressApp

Declaration

C#

[TypeConverter(typeof(BusinessClassTypeConverter<object>))]
[DefaultValue(null)]
public Type TargetObjectType { get; set; }

VB.NET

<TypeConverter(GetType(BusinessClassTypeConverter(Of Object)))>
<DefaultValue(Nothing)>
Public Property TargetObjectType As Type

Property Value

Type	Default	Description
Type	null	An object’s type.

Remarks

View Controllers are activated for both Windows and Frames. However, you can specify the type of objects represented by a View to provide a View Controller activation. For this purpose, specify the TargetObjectType property in code or the Designer.

To make a single View Controller available in Views of different business object types simultaneously, set the TargetObjectType property in code to an interface or their base class type, which is implemented or inherited by all these business types respectively. Also, for the same task, you can specify several View identifiers using the ViewController.TargetViewId property.

Note

The TargetObjectType property affects only ViewController’s activation. Controller.FrameAssigned and other events that are irrelevant to the object type always fire.

The following example creates a List View and displays it via a PopupWindowShowAction.

C#

using System;
using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Actions;
using DevExpress.Persistent.Base;
using DevExpress.Persistent.BaseImpl;
// ...
public class ShowListViewController : ViewController {
    public ShowListViewController() {
        PopupWindowShowAction showListViewAction = new PopupWindowShowAction(this, "ShowListView",
            PredefinedCategory.Edit);
        this.TargetObjectType = typeof(Note);
        showListViewAction.CustomizePopupWindowParams += ShowListViewAction_CustomizePopupWindowParams;
    }
    private void ShowListViewAction_CustomizePopupWindowParams(object sender, CustomizePopupWindowParamsEventArgs e) {
        Type objectType = typeof(Person);
        e.View = Application.CreateListView(objectType, true);
    }
}

VB.NET

Imports System
Imports DevExpress.ExpressApp
Imports DevExpress.ExpressApp.Actions
Imports DevExpress.Persistent.Base
Imports DevExpress.Persistent.BaseImpl

Public Class ShowListViewController
    Inherits ViewController
    Public Sub New()
        Dim showListViewAction As New PopupWindowShowAction(Me, "ShowListView", PredefinedCategory.Edit)
        Me.TargetObjectType = GetType(Note)
        AddHandler showListViewAction.CustomizePopupWindowParams, _
            AddressOf ShowListViewAction_CustomizePopupWindowParams
    End Sub
    Private Sub ShowListViewAction_CustomizePopupWindowParams(ByVal sender As Object, _
        ByVal e As CustomizePopupWindowParamsEventArgs)
        Dim objectType As Type = GetType(Person)
        e.View = Application.CreateListView(objectType, True)
    End Sub
End Class

Alternatively, you can implement the generic ObjectViewController<ViewType, ObjectType> Controller instead of the ViewController and specify the View and object type for which this Controller should be activated in the ViewType and ObjectType generic parameters.