Form.TopLevel Property

 

Gets or sets a value indicating whether to display the form as a top-level window.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

<BrowsableAttribute(False)>
Public Property TopLevel As Boolean

Property Value

Type: System.Boolean

true to display the form as a top-level window; otherwise, false. The default is true.

Exception Condition
Exception

A Multiple-document interface (MDI) parent form must be a top-level window.

A top-level form is a window that has no parent form, or whose parent form is the desktop window. Top-level windows are typically used as the main form in an application.

The following code example use the Modal property to determine if a form is displayed as a modal form. If it is not the FormBorderStyle and TopLevel properties are changed to make the form non-top-level form with a tool window border.

Private Sub ShowMyNonModalForm()
    Dim myForm As New Form()
    myForm.Text = "My Form"
    myForm.SetBounds(10, 10, 200, 200)

    myForm.Show()
    ' Determine if the form is modal.
    If myForm.Modal = False Then
        ' Change borderstyle and make it not a top level window.
        myForm.FormBorderStyle = FormBorderStyle.FixedToolWindow
        myForm.TopLevel = False
    End If
End Sub

.NET Framework
Available since 1.1
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