Specifies the value to pass to a property to cause the property to get its value from another source. This is known as ambience. This class cannot be inherited.
Assembly: System (in System.dll)
If a property on a control has ambient behavior, this attribute must be present. Ambient properties query their parent for their value, for example, a Control.Font property or a Control.BackColor property.
Typically, a visual designer uses the attribute to decide which value to persist for a property. This is usually a value that causes the property to get its value from another source. An example of an ambient value is Color.Empty as the ambient value for the BackColor property. If you have a control on a form and the BackColor property of the control is set to a different color than the BackColor property of the form, you can reset the BackColor property of the control to that of the form by setting the BackColor of the control to Color.Empty.
The following code example demonstrates using to enforce ambient behavior for a property called AlertForeColor. For a full code listing, see How to: Apply Attributes in Windows Forms Controls.
<AmbientValue(GetType(Color), "Empty"), _ Category("Appearance"), _ DefaultValue(GetType(Color), "White"), _ Description("The color used for painting alert text.")> _ Public Property AlertForeColor() As Color Get If Me.alertForeColorValue = Color.Empty AndAlso (Me.Parent IsNot Nothing) Then Return Parent.ForeColor End If Return Me.alertForeColorValue End Get Set(ByVal value As Color) Me.alertForeColorValue = value End Set End Property ' This method is used by designers to enable resetting the ' property to its default value. Public Sub ResetAlertForeColor() Me.AlertForeColor = AttributesDemoControl.defaultAlertForeColorValue End Sub ' This method indicates to designers whether the property ' value is different from the ambient value, in which case ' the designer should persist the value. Private Function ShouldSerializeAlertForeColor() As Boolean Return Me.alertForeColorValue <> AttributesDemoControl.ambientColorValue End Function
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.