Form.TopLevel Property

Reference

Definition

Namespace:: System.Windows.Forms

Assembly:: System.Windows.Forms.dll

Source:: Form.cs

Source:: Form.cs

Source:: Form.cs

Important

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

public:
 property bool TopLevel { bool get(); void set(bool value); };

[System.ComponentModel.Browsable(false)]
public bool TopLevel { get; set; }

[<System.ComponentModel.Browsable(false)>]
member this.TopLevel : bool with get, set

Public Property TopLevel As Boolean

Property Value

Boolean

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

Attributes: BrowsableAttribute

Exceptions

Exception

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

Examples

The following 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:
   void ShowMyNonModalForm()
   {
      Form^ myForm = gcnew Form;
      myForm->Text = "My Form";
      myForm->SetBounds( 10, 10, 200, 200 );
      myForm->Show();

      // Determine if the form is modal.
      if ( !myForm->Modal )
      {
         // Change borderstyle and make it not a top level window.
         myForm->FormBorderStyle = ::FormBorderStyle::FixedToolWindow;
         myForm->TopLevel = false;
      }
   }

private void ShowMyNonModalForm()
{
    Form myForm = new Form();
    myForm.Text = "My Form";
    myForm.SetBounds(10,10,200,200);

    myForm.Show();
    // Determine if the form is modal.
    if (!myForm.Modal)
    {
        // Change borderstyle and make it not a top level window.
        myForm.FormBorderStyle = FormBorderStyle.FixedToolWindow;
        myForm.TopLevel = false;
    }
}

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

Remarks

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.

Applies to

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