Form.ControlBox Property

Gets or sets a value indicating whether a control box is displayed in the caption bar of the form.

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

public bool ControlBox { get; set; }
/** @property */
public boolean get_ControlBox ()

/** @property */
public void set_ControlBox (boolean value)

public function get ControlBox () : boolean

public function set ControlBox (value : boolean)

Property Value

true if the form displays a control box in the upper left corner of the form; otherwise, false. The default is true.

If the ControlBox property is set to true, the control box is displayed in the upper-left corner of the caption bar. The control box is where the user can click to access the system menu.


When set to false, the ControlBox property has no effect on a Multiple-document interface (MDI) child form that is displayed maximized at time of creation.

The following code example uses the ControlBox, FormBorderStyle, MaximizeBox, MinimizeBox, and StartPosition properties to create a form that does not have any border or caption box. The form created in this example could be used to create a splash screen for an application. The example requires that the example's method is defined in a form class and called when the form is being initialized.

public void CreateMyBorderlessWindow()
    this.FormBorderStyle = FormBorderStyle.None;
    this.MaximizeBox = false;
    this.MinimizeBox = false;
    this.StartPosition = FormStartPosition.CenterScreen;
    // Remove the control box so the form will only display client area.
    this.ControlBox = false;

public void CreateMyBorderlessWindow()

    // Remove the control box so the form will only display client area.
} //CreateMyBorderlessWindow

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0