Attribute.IsDefined Method (MemberInfo, Type, Boolean)
Determines whether any custom attributes are applied to a member of a type. Parameters specify the member, the type of the custom attribute to search for, and whether to search ancestors of the member.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- element
-
Type:
System.Reflection.MemberInfo
An object derived from the MemberInfo class that describes a constructor, event, field, method, type, or property member of a class.
- attributeType
-
Type:
System.Type
The type, or a base type, of the custom attribute to search for.
- inherit
-
Type:
System.Boolean
If true, specifies to also search the ancestors of element for custom attributes.
Return Value
Type: System.Booleantrue if a custom attribute of type attributeType is applied to element; otherwise, false.
| Exception | Condition |
|---|---|
| ArgumentNullException | element or attributeType is null. |
| ArgumentException | attributeType is not derived from Attribute. |
| NotSupportedException | element is not a constructor, method, property, event, type, or field. |
Note |
|---|
Starting with the .NET Framework version 2.0, this method returns true if a type, method, or constructor has security attributes stored in the new metadata format. Assemblies compiled with version 2.0 or later use the new format. Dynamic assemblies and assemblies compiled with earlier versions of the .NET Framework use the old XML format. See Emitting Declarative Security Attributes. |
The following code example illustrates the use of IsDefined, taking a MemberInfo as a parameter.
using System; using System.Reflection; namespace IsDef4CS { public class TestClass { // Assign the Obsolete attribute to a method. [Obsolete("This method is obsolete. Use Method2 instead.")] public void Method1() {} public void Method2() {} } public class DemoClass { static void Main(string[] args) { // Get the class type to access its metadata. Type clsType = typeof(TestClass); // Get the MethodInfo object for Method1. MethodInfo mInfo = clsType.GetMethod("Method1"); // See if the Obsolete attribute is defined for this method. bool isDef = Attribute.IsDefined(mInfo, typeof(ObsoleteAttribute)); // Display the result. Console.WriteLine("The Obsolete Attribute {0} defined for {1} of class {2}.", isDef ? "is" : "is not", mInfo.Name, clsType.Name); // If it's defined, display the attribute's message. if (isDef) { ObsoleteAttribute obsAttr = (ObsoleteAttribute)Attribute.GetCustomAttribute( mInfo, typeof(ObsoleteAttribute)); if (obsAttr != null) Console.WriteLine("The message is: \"{0}\".", obsAttr.Message); else Console.WriteLine("The message could not be retrieved."); } } } } /* * Output: * The Obsolete Attribute is defined for Method1 of class TestClass. * The message is: "This method is obsolete. Use Method2 instead.". */
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
