Attribute.GetCustomAttribute Method (Assembly, Type)
Retrieves a custom attribute applied to a specified assembly. Parameters specify the assembly and the type of the custom attribute to search for.
Assembly: mscorlib (in mscorlib.dll)
Public Shared Function GetCustomAttribute ( element As Assembly, attributeType As Type ) As Attribute
Parameters
- element
-
Type:
System.Reflection.Assembly
An object derived from the Assembly class that describes a reusable collection of modules.
- attributeType
-
Type:
System.Type
The type, or a base type, of the custom attribute to search for.
Return Value
Type: System.AttributeA reference to the single custom attribute of type attributeType that is applied to element, or null if there is no such attribute.
| Exception | Condition |
|---|---|
| ArgumentNullException | element or attributeType is null. |
| ArgumentException | attributeType is not derived from Attribute. |
| AmbiguousMatchException | More than one of the requested attributes was found. |
Use the GetCustomAttributes method if you expect more than one value to be returned, or AmbiguousMatchException will be thrown.
Note |
|---|
Starting with the .NET Framework version 2.0, this method returns security attributes if the attributes are 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 the GetCustomAttribute method taking an Assembly as a parameter.
Imports System Imports System.Reflection Imports Microsoft.VisualBasic ' Add an AssemblyDescription attribute. <Assembly: AssemblyDescription("A sample description")> Module DemoModule Sub Main() ' Get the assembly for this module. Dim assy As System.Reflection.Assembly = GetType(DemoModule).Assembly ' Store the assembly name. Dim assyName As String = assy.GetName().Name ' See if the AssemblyDescription attribute is defined. If Attribute.IsDefined(assy, GetType(AssemblyDescriptionAttribute)) _ Then ' Affirm that the attribute is defined. Assume the filename of ' this code example is "IsDef1VB". Console.WriteLine("The AssemblyDescription attribute is " & _ "defined for assembly {0}.", assyName) ' Get the description attribute itself. Dim attr As Attribute = Attribute.GetCustomAttribute( _ assy, GetType(AssemblyDescriptionAttribute)) ' Display the description. If Not attr Is Nothing And _ TypeOf attr Is AssemblyDescriptionAttribute Then Dim adAttr As AssemblyDescriptionAttribute = _ CType(attr, AssemblyDescriptionAttribute) Console.WriteLine("The description is " & _ Chr(34) & "{0}" & Chr(34) & ".", adAttr.Description) Else Console.WriteLine("The description could not be retrieved.") End If Else Console.WriteLine("The AssemblyDescription attribute is not " & _ "defined for assembly {0}.", assyName) End If End Sub End Module ' Output: ' The AssemblyDescription attribute is defined for assembly IsDef1VB. ' The description is "A sample description".
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
