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.NET Framework Class Library

Control.DesignMode Property

Gets a value indicating whether a control is being used on a design surface.

Namespace:  System.Web.UI
Assembly:  System.Web (in System.Web.dll)
Protected Friend ReadOnly Property DesignMode As Boolean

Property Value

Type: System.Boolean
true if the control is being used in a designer; otherwise, false.

The DesignMode property returns true to indicate that the control is being used in the context of a designer. Your custom controls can use this property when design-time behavior is different than run-time behavior.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

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.