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Control::SetTopLevel Method

Sets the control as the top-level control.

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

protected:
void SetTopLevel(
	bool value
)

Parameters

value
Type: System::Boolean

true to set the control as the top-level control; otherwise, false.

ExceptionCondition
InvalidOperationException

The value parameter is set to true and the control is an ActiveX control.

Exception

The GetTopLevel return value is not equal to the value parameter and the Parent property is not nullptr.

If you call the SetTopLevel method of a Form and pass in a value of false, the form will not be visible until you call SetTopLevel again, passing in a value of true.

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

  • UIPermission 

    to set the control as a top-level control if it is of type Form. This permission is only demanded if the value parameter is true and the control is not an ActiveX control. Associated enumeration: SafeTopLevelWindows value of UIPermissionWindow.

  • UIPermission 

    to set the control as a top-level control if it is of any type other than Form. This permission is only demanded if the value parameter is true and the control is not an ActiveX control. Associated enumeration: AllWindows value of UIPermissionWindow.

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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