How to: Show a Custom Windows Form

• Jun 11, 2021
• 4 minutes to read

In XAF WinForms applications, it is possible to show custom windows using standard Windows Forms approaches, such as the Form.Show and Form.ShowDialog methods. If a Form should show data from the application’s database, it is possible to use XAF mechanisms for CRUD operations using the IObjectSpace interface. This topic demonstrates how to initialize and show a custom Form when an XAF Action is clicked.

Show a Custom Window

The steps below describe how to show a custom window on an Action‘s Execute event.

• Create and design a custom Form, for example, a NonXAFForm.
• Create a new ViewController descendant and add a new SimpleAction in its constructor.
• Create a new NonXAFForm instance in the Action’s Execute event handler.

• Invoke the window using the Form.ShowDialog method.

  C#

  using DevExpress.ExpressApp;
  using DevExpress.ExpressApp.Actions;
  using System.Windows.Forms;
  //...
  public class ShowWindowController : ViewController {
      public ShowWindowController() {
          SimpleAction showWindowAction = new SimpleAction(this, "ShowWindow", 
  DevExpress.Persistent.Base.PredefinedCategory.View);
          showWindowAction.ImageName = "ModelEditor_Views";
          showWindowAction.Execute += 
  new SimpleActionExecuteEventHandler(showWindowAction_Execute);
      }
      void showWindowAction_Execute(object sender, SimpleActionExecuteEventArgs e) {
          NonXAFForm form = new NonXAFForm();
          //...
          form.ShowDialog();
      }
  }
  

  VB.NET

  Imports DevExpress.ExpressApp
  Imports DevExpress.ExpressApp.Actions
  Imports System.Windows.Forms
  '...
  Public Class ShowWindowController
      Inherits ViewController
      Public Sub New()
          Dim showWindowAction As New SimpleAction(Me, "ShowWindow", _
  DevExpress.Persistent.Base.PredefinedCategory.View)
          showWindowAction.ImageName = "ModelEditor_Views"
          AddHandler showWindowAction.Execute, AddressOf showWindowAction_Execute
      End Sub
      Private Sub showWindowAction_Execute(ByVal sender As Object, _
  ByVal e As SimpleActionExecuteEventArgs)
          Dim form As New NonXAFForm()
          //...
          form.ShowDialog()
      End Sub
  End Class
  

Show a Custom Window with XAF Data

In this example, a custom window with a control that displays XAF data is invoked when an Action‘s Execute event occurs. The DataGridView control is used here for demonstration purposes. Follow the steps below to implement this behavior:

• Create a new ViewController descendant and add a new SimpleAction in its constructor.
• In the Action’s Execute event handler, create a new form instance.
• Create a new IObjectSpace instance using the XafApplication.CreateObjectSpace method.
• Get a Contact type objects collection using the IObjectSpace.CreateCollection method and set it as the DataGridView control’s data source.
• Place the DataGridView control on the Form and invoke this Form using the Form.ShowDialog method.

C#

using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Actions;
using System.Collections;
using System.Windows.Forms;
//...
public class ShowWindowController : ViewController {
    public ShowWindowController() {
        SimpleAction showWindowAction = new SimpleAction(this, "ShowWindow", 
DevExpress.Persistent.Base.PredefinedCategory.View);
        showWindowAction.ImageName = "ModelEditor_Views";
        showWindowAction.Execute += 
new SimpleActionExecuteEventHandler(showWindowAction_Execute);
    }
    void showWindowAction_Execute(object sender, SimpleActionExecuteEventArgs e) {
        Form form = new Form();
        form.Text = "Form with XAF Data";
        IObjectSpace objectSpace = Application.CreateObjectSpace(typeof(Contact));
        IList contactsCollection = objectSpace.CreateCollection(typeof(Contact));
        DataGridView dataGridView = new DataGridView();
        dataGridView.DataSource = contactsCollection;
        dataGridView.Dock = DockStyle.Fill;
        form.Controls.Add(dataGridView);
        form.ShowDialog();
    }
}

VB.NET

Imports DevExpress.ExpressApp
Imports DevExpress.ExpressApp.Actions
Imports System.Collections
Imports System.Windows.Forms
'...
Public Class ShowWindowController
    Inherits ViewController
    Public Sub New()
        Dim showWindowAction As New SimpleAction(Me, "ShowWindow", _
DevExpress.Persistent.Base.PredefinedCategory.View)
        showWindowAction.ImageName = "ModelEditor_Views"
        AddHandler showWindowAction.Execute, AddressOf showWindowAction_Execute
    End Sub
    Private Sub showWindowAction_Execute(ByVal sender As Object, _
ByVal e As SimpleActionExecuteEventArgs)
        Dim form As New Form()
        form.Text = "Form with XAF Data"
        Dim objectSpace As IObjectSpace = Application.CreateObjectSpace(GetType(Contact))
        Dim contactsCollection As IList = objectSpace.CreateCollection(GetType(Contact))
        Dim dataGridView As New DataGridView()
        dataGridView.DataSource = contactsCollection
        dataGridView.Dock = DockStyle.Fill
        form.Controls.Add(dataGridView)
        form.ShowDialog()
    End Sub
End Class

You can display XAF data in a control of an existing form by adding the form’s constructor with the IObjectSpace parameter. In this constructor, specify the control’s DataSource property using the IObjectSpace.GetObjects method. The code snippet below shows an example of this constructor.

C#

using System.Windows.Forms;
using DevExpress.ExpressApp;
using DevExpress.XtraEditors;
//...
public partial class NonXAFForm : XtraForm {
    //...
    private IObjectSpace objectSpace;
    public NonXAFForm(IObjectSpace objectSpace) : base() {
        InitializeComponent();
        this.objectSpace = objectSpace;
        dataGridView1.DataSource = objectSpace.GetObjects(typeof(Contact));
        //...
    }
}

VB.NET

Imports System.Windows.Forms
Imports DevExpress.ExpressApp
Imports DevExpress.XtraEditors
'...
Partial Public Class NonXAFForm
    Inherits XtraForm
    '...
    Private objectSpace As IObjectSpace
    Public Sub New(ByVal objectSpace As IObjectSpace)
        MyBase.New()
        InitializeComponent()
        Me.objectSpace = objectSpace
        dataGridView1.DataSource = objectSpace.GetObjects(GetType(Contact))
        '...
    End Sub
End Class