IsDefined Method (Module, Type, Boolean)

Attribute.IsDefined Method (Module, Type, Boolean)

Determines whether any custom attributes are applied to a module. Parameters specify the module, the type of the custom attribute to search for, and an ignored search option.

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

public static bool IsDefined(
	Module element,
	Type attributeType,
	bool inherit


Type: System.Reflection.Module
An object derived from the Module class that describes a portable executable file.
Type: System.Type
The type, or a base type, of the custom attribute to search for.
Type: System.Boolean
This parameter is ignored, and does not affect the operation of this method.

Return Value

Type: System.Boolean
true if a custom attribute of type attributeType is applied to element; otherwise, false.


element or attributeType is null.


attributeType is not derived from Attribute.

This method ignores the inherit parameter and does not search the ancestors of element for custom attributes.

The following code example illustrates the use of IsDefined, taking a Module as a parameter.

using System;
using System.Diagnostics;

// Add the Debuggable attribute to the module.
[module:Debuggable(true, false)]
namespace IsDef2CS
    public class DemoClass
        static void Main(string[] args)
            // Get the class type to access its metadata.
            Type clsType = typeof(DemoClass);
            // See if the Debuggable attribute is defined for this module.
            bool isDef = Attribute.IsDefined(clsType.Module, 
            // Display the result.
            Console.WriteLine("The Debuggable attribute {0} " +
                "defined for Module {1}.",
                isDef ? "is" : "is not",
            // If the attribute is defined, display the JIT settings.
            if (isDef)
                // Retrieve the attribute itself.
                DebuggableAttribute dbgAttr = (DebuggableAttribute)
                if (dbgAttr != null)
                    Console.WriteLine("JITTrackingEnabled is {0}.",
                    Console.WriteLine("JITOptimizerDisabled is {0}.",
                    Console.WriteLine("The Debuggable attribute " +
                        "could not be retrieved.");

 * Output:
 * The Debuggable attribute is defined for Module IsDef2CS.exe.
 * JITTrackingEnabled is True.
 * JITOptimizerDisabled is False.

.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

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.

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