Attribute.GetCustomAttributes Method (Assembly, Type) (System)

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.NET Framework Class Library

Attribute.GetCustomAttributes Method (Assembly, Type)

Retrieves an array of the custom attributes applied to an assembly. Parameters specify the assembly, and the type of the custom attribute to search for.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

Syntax

Visual Basic

Public Shared Function GetCustomAttributes ( _
	element As Assembly, _
	attributeType As Type _
) As Attribute()

public static Attribute[] GetCustomAttributes(
	Assembly element,
	Type attributeType
)

Visual C++

public:
static array<Attribute^>^ GetCustomAttributes(
	Assembly^ element, 
	Type^ attributeType
)

static member GetCustomAttributes : 
        element:Assembly * 
        attributeType:Type -> 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.Attribute[]
An Attribute array that contains the custom attributes of type attributeType applied to element, or an empty array if no such custom attributes exist.

Exceptions

Exception	Condition
ArgumentNullException	element or attributeType is null.
ArgumentException	attributeType is not derived from Attribute.

Remarks

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.

Examples

The following code example demonstrates the use of GetCustomAttributes, taking an Assembly as a parameter.

Visual Basic


Imports System
Imports System.Reflection
Imports Microsoft.VisualBasic

<Assembly: AssemblyTitle("CustAttrs1VB")> 
<Assembly: AssemblyDescription("GetCustomAttributes() Demo")> 
<Assembly: AssemblyCompany("Microsoft")> 

Module DemoModule

    Sub Main()
        ' Get the Assembly type to access its metadata.
        Dim assy As Reflection.Assembly = GetType(DemoModule).Assembly
        Dim attr As Attribute

        ' Iterate through all the attributes for the assembly.
        For Each attr In Attribute.GetCustomAttributes(assy)

            ' Check for the AssemblyTitle attribute.
            If TypeOf attr Is AssemblyTitleAttribute Then
                ' Convert the attribute to access its data.
                Dim attrTitle As AssemblyTitleAttribute = _
                    CType(attr, AssemblyTitleAttribute)
                Console.WriteLine("Assembly title is ""{0}"".", _
                    attrTitle.Title)

            ' Check for the AssemblyDescription attribute.
            ElseIf TypeOf attr Is AssemblyDescriptionAttribute Then
                ' Convert the attribute to access its data.
                Dim attrDesc As AssemblyDescriptionAttribute = _
                    CType(attr, AssemblyDescriptionAttribute)
                Console.WriteLine("Assembly description is ""{0}"".", _
                    attrDesc.Description)

            ' Check for the AssemblyCompany attribute.
            ElseIf TypeOf attr Is AssemblyCompanyAttribute Then
                ' Convert the attribute to access its data.
                Dim attrComp As AssemblyCompanyAttribute = _
                    CType(attr, AssemblyCompanyAttribute)
                Console.WriteLine("Assembly company is {0}.", _
                    attrComp.Company)
            End If
        Next
    End Sub
End Module

' Output:
' Assembly company is Microsoft.
' Assembly description is "GetCustomAttributes() Demo".
' Assembly title is "CustAttrs1VB".


using System;
using System.Reflection;

[assembly: AssemblyTitle("CustAttrs1CS")]
[assembly: AssemblyDescription("GetCustomAttributes() Demo")]
[assembly: AssemblyCompany("Microsoft")]

namespace CustAttrs1CS {
    class DemoClass {
        static void Main(string[] args) {
            Type clsType = typeof(DemoClass);
            // Get the Assembly type to access its metadata.
            Assembly assy = clsType.Assembly;

            // Iterate through the attributes for the assembly.
            foreach(Attribute attr in Attribute.GetCustomAttributes(assy)) {
                // Check for the AssemblyTitle attribute.
                if (attr.GetType() == typeof(AssemblyTitleAttribute))
                    Console.WriteLine("Assembly title is \"{0}\".",
                        ((AssemblyTitleAttribute)attr).Title);

                // Check for the AssemblyDescription attribute.
                else if (attr.GetType() == 
                    typeof(AssemblyDescriptionAttribute))
                    Console.WriteLine("Assembly description is \"{0}\".",
                        ((AssemblyDescriptionAttribute)attr).Description);

                // Check for the AssemblyCompany attribute.
                else if (attr.GetType() == typeof(AssemblyCompanyAttribute))
                    Console.WriteLine("Assembly company is {0}.",
                        ((AssemblyCompanyAttribute)attr).Company);
            }
        }
    }
}

/*
 * Output:
 * Assembly company is Microsoft.
 * Assembly description is "GetCustomAttributes() Demo".
 * Assembly title is "CustAttrs1CS".
 */

Visual C++


#using <System.dll>

using namespace System;
using namespace System::Reflection;

[assembly:AssemblyTitle("CustAttrs1CS")];
[assembly:AssemblyDescription("GetCustomAttributes() Demo")];
[assembly:AssemblyCompany("Microsoft")];
namespace CustAttrs1CS
{
   ref class DemoClass
   {
   public:
      static void Main()
      {
         Type^ clsType = DemoClass::typeid;

         // Get the Assembly type to access its metadata.
         Assembly^ assy = clsType->Assembly;

         // Iterate through the attributes for the assembly.
         System::Collections::IEnumerator^ myEnum = Attribute::GetCustomAttributes( assy )->GetEnumerator();
         while ( myEnum->MoveNext() )
         {
            Attribute^ attr = safe_cast<Attribute^>(myEnum->Current);

            // Check for the AssemblyTitle attribute.
            if ( attr->GetType() == AssemblyTitleAttribute::typeid )
                        Console::WriteLine( "Assembly title is \"{0}\".", (dynamic_cast<AssemblyTitleAttribute^>(attr))->Title );
            // Check for the AssemblyDescription attribute.
            else

            // Check for the AssemblyDescription attribute.
            if ( attr->GetType() == AssemblyDescriptionAttribute::typeid )
                        Console::WriteLine( "Assembly description is \"{0}\".", (dynamic_cast<AssemblyDescriptionAttribute^>(attr))->Description );
            // Check for the AssemblyCompany attribute.
            else

            // Check for the AssemblyCompany attribute.
            if ( attr->GetType() == AssemblyCompanyAttribute::typeid )
                        Console::WriteLine( "Assembly company is {0}.", (dynamic_cast<AssemblyCompanyAttribute^>(attr))->Company );
         }
      }
   };
}


/*
 * Output:
 * Assembly company is Microsoft.
 * Assembly description is "GetCustomAttributes() Demo".
 * Assembly title is "CustAttrs1CS".
 */

Version Information

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Reference

Attribute Class

GetCustomAttributes Overload

System Namespace