My.Application.OpenForms Property

Article
11/18/2006

Gets a collection of all the application's open forms.

' Usage
Dim value As System.Windows.Forms.FormCollection = My.Application.OpenForms
' Declaration
Public ReadOnly Property OpenForms As System.Windows.Forms.FormCollection

Return Value

A FormCollection object that contains all of the application's open forms.

Remarks

The My.Application.OpenForms property gets a collection of all the application's open forms. The behavior is identical to the System.Windows.Forms.Application.OpenForms property.

Note

The My.Application.OpenForms property returns all open forms, regardless of which thread opened them. You should check the InvokeRequired property of each form before accessing it; otherwise, it might throw an InvalidOperationException exception. For more information, see How to: Access All Open Forms of an Application.

Tasks

The following table lists examples of tasks involving the My.Application.OpenForms property.

To	See
Display the titles of all the application's open forms	How to: Access All Open Forms of an Application

Example

This example loops over the application's open forms, selects the ones directly accessible by the current thread, and displays their titles in a ListBox control. To access the open forms, see How to: Access All Open Forms of an Application.

Private Sub GetOpenFormTitles()
    Dim formTitles As New Collection

    Try
        For Each f As Form In My.Application.OpenForms
            If Not f.InvokeRequired Then
                ' Can access the form directly.
                formTitles.Add(f.Text)
            End If
        Next
    Catch ex As Exception
        formTitles.Add("Error: " & ex.Message)
    End Try

    Form1.ListBox1.DataSource = formTitles
End Sub

This example requires that your Windows Forms application have a form named Form1 that contains a list box named ListBox1.

Requirements

Namespace: Microsoft.VisualBasic.ApplicationServices

Class: WindowsFormsApplicationBase

Assembly: Visual Basic Runtime Library (in Microsoft.VisualBasic.dll)

Availability by Project Type

Project type	Available
Windows Application	Yes
Class Library	No
Console Application	No
Windows Control Library	No
Web Control Library	No
Windows Service	No
Web Site	No

Permissions

The following permission may be necessary:

Permission	Description
UIPermission	Controls the permissions related to user interfaces and the clipboard. Associated enumeration: AllWindows.

For more information, see Code Access Security and Requesting Permissions.

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