DefaultValueAttribute Class
Updated: September 2008
Specifies the default value for a property.
Assembly: System (in System.dll)
You can create a DefaultValueAttribute with any value. A member's default value is typically its initial value. A visual designer can use the default value to reset the member's value. Code generators can use the default values also to determine whether code should be generated for the member.
Note: |
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A DefaultValueAttribute will not cause a member to be automatically initialized with the attribute's value. You must set the initial value in your code. |
For more information, see Attributes Overview and Extending Metadata Using Attributes.
| Topic | Location |
|---|---|
| Developing Custom Data-Bound Web Server Controls for ASP.NET 1.1 | Authoring ASP.NET Controls |
| Walkthrough: Developing and Using a Custom Server Control | Authoring ASP.NET Controls |
| Developing Custom Data-Bound Web Server Controls for ASP.NET 2.0 | Authoring ASP.NET Controls |
| Walkthrough: Creating a Custom Data-Bound ASP.NET Web Control for ASP.NET 2.0 | Authoring ASP.NET Controls |
| Walkthrough: Creating a Custom Data-Bound ASP.NET Web Control for ASP.NET 1.1 | Authoring ASP.NET Controls |
| Walkthrough: Developing and Using a Custom Server Control | Authoring ASP.NET Controls |
| Developing Custom Data-Bound Web Server Controls for ASP.NET 1.1 | Authoring ASP.NET Controls |
| Developing Custom Data-Bound Web Server Controls for ASP.NET 2.0 | Authoring ASP.NET Controls |
| Walkthrough: Creating a Custom Data-Bound ASP.NET Web Control for ASP.NET 2.0 | Authoring ASP.NET Controls |
| Walkthrough: Creating a Custom Data-Bound ASP.NET Web Control for ASP.NET 1.1 | Authoring ASP.NET Controls |
The following example sets the default value of MyProperty to false.
The next example checks the default value of MyProperty. First the code gets a PropertyDescriptorCollection with all the properties for the object. Next it indexes into the PropertyDescriptorCollection to get MyProperty. Then it returns the attributes for this property and saves them in the attributes variable.
The example then prints the default value by retrieving the DefaultValueAttribute from the AttributeCollection, and writing its name to the console screen.
' Gets the attributes for the property. Dim attributes As AttributeCollection = _ TypeDescriptor.GetProperties(Me)("MyProperty").Attributes ' Prints the default value by retrieving the DefaultValueAttribute ' from the AttributeCollection. Dim myAttribute As DefaultValueAttribute = _ CType(attributes(GetType(DefaultValueAttribute)), DefaultValueAttribute) Console.WriteLine(("The default value is: " & myAttribute.Value.ToString()))
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, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
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.
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