Guid Structure

Represents a globally unique identifier (GUID).

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

[SerializableAttribute]
[ComVisibleAttribute(true)]
public struct Guid : IFormattable, IComparable, 
	IComparable<Guid>, IEquatable<Guid>

The Guid type exposes the following members.

  NameDescription
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryGuid(Byte[])Initializes a new instance of the Guid structure using the specified array of bytes.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryGuid(String)Initializes a new instance of the Guid structure using the value represented by the specified string.
Public methodSupported by the XNA FrameworkGuid(Int32, Int16, Int16, Byte[])Initializes a new instance of the Guid structure using the specified integers and byte array.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryGuid(Int32, Int16, Int16, Byte, Byte, Byte, Byte, Byte, Byte, Byte, Byte)Initializes a new instance of the Guid structure using the specified integers and bytes.
Public methodGuid(UInt32, UInt16, UInt16, Byte, Byte, Byte, Byte, Byte, Byte, Byte, Byte)Initializes a new instance of the Guid structure using the specified unsigned integers and bytes.
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  NameDescription
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryCompareTo(Guid)Compares this instance to a specified Guid object and returns an indication of their relative values.
Public methodSupported by the XNA FrameworkCompareTo(Object)Compares this instance to a specified object and returns an indication of their relative values.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryEquals(Guid)Returns a value indicating whether this instance and a specified Guid object represent the same value.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryEquals(Object)Returns a value that indicates whether this instance is equal to a specified object. (Overrides ValueType.Equals(Object).)
Protected methodSupported by the XNA FrameworkSupported by Portable Class LibraryFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryGetHashCodeReturns the hash code for this instance. (Overrides ValueType.GetHashCode().)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodSupported by the XNA FrameworkSupported by Portable Class LibraryMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodStatic memberSupported by the XNA FrameworkSupported by Portable Class LibraryNewGuidInitializes a new instance of the Guid structure.
Public methodStatic memberParseConverts the string representation of a GUID to the equivalent Guid structure.
Public methodStatic memberParseExactConverts the string representation of a GUID to the equivalent Guid structure, provided that the string is in the specified format.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryToByteArrayReturns a 16-element byte array that contains the value of this instance.
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryToString()Returns a string representation of the value of this instance in registry format. (Overrides ValueType.ToString().)
Public methodSupported by the XNA FrameworkSupported by Portable Class LibraryToString(String)Returns a string representation of the value of this Guid instance, according to the provided format specifier.
Public methodSupported by the XNA FrameworkToString(String, IFormatProvider)Returns a string representation of the value of this instance of the Guid structure, according to the provided format specifier and culture-specific format information.
Public methodStatic memberTryParseConverts the string representation of a GUID to the equivalent Guid structure.
Public methodStatic memberTryParseExactConverts the string representation of a GUID to the equivalent Guid structure, provided that the string is in the specified format.
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  NameDescription
Public operatorStatic memberSupported by the XNA FrameworkSupported by Portable Class LibraryEqualityIndicates whether the values of two specified Guid objects are equal.
Public operatorStatic memberSupported by the XNA FrameworkSupported by Portable Class LibraryInequalityIndicates whether the values of two specified Guid objects are not equal.
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  NameDescription
Public fieldStatic memberSupported by the XNA FrameworkSupported by Portable Class LibraryEmptyA read-only instance of the Guid structure whose value is all zeros.
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  NameDescription
Explicit interface implemetationPrivate methodSupported by Portable Class LibraryIFormattable.ToStringReturns a string representation of the value of this instance, according to the provided format specifier and culture-specific format information.
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A GUID is a 128-bit integer (16 bytes) that can be used across all computers and networks wherever a unique identifier is required. Such an identifier has a very low probability of being duplicated.

The following example uses the System.Runtime.InteropServices.GuidAttribute class to assign a GUID to a user-defined class and an interface. It retrieves the value of the GUID by calling the GetCustomAttribute method and compares it with two other GUIDs to determine whether they are equal.


using System;
using System.Runtime.InteropServices;

// Guid for the interface IMyInterface.
[Guid("F9168C5E-CEB2-4faa-B6BF-329BF39FA1E4")]
interface IMyInterface
{
    void MyMethod();
}

// Guid for the coclass MyTestClass.
[Guid("936DA01F-9ABD-4d9d-80C7-02AF85C822A8")]
public class MyTestClass : IMyInterface
{
    public void MyMethod() {}

    public static void Main( string []args )
    {
        GuidAttribute IMyInterfaceAttribute = (GuidAttribute) Attribute.GetCustomAttribute(typeof(IMyInterface), typeof(GuidAttribute));

        // The Value property of GuidAttribute returns a string. 
        System.Console.WriteLine("IMyInterface Attribute: " + IMyInterfaceAttribute.Value );    

        // Using the string to create a guid.
        Guid myGuid1 = new Guid(IMyInterfaceAttribute.Value );
        // Using a byte array to create a guid.
        Guid myGuid2 = new Guid(myGuid1.ToByteArray());

        // Equals is overridden to perform a value comparison.
        if (myGuid1.Equals(myGuid2))
            System.Console.WriteLine("myGuid1 equals myGuid2");
        else
            System.Console.WriteLine("myGuid1 does not equal myGuid2" );

        // Equality operator can also be used to determine if two guids have same value.
        if ( myGuid1 == myGuid2 )
            System.Console.WriteLine( "myGuid1 == myGuid2" );
        else
            System.Console.WriteLine( "myGuid1 != myGuid2" );
    }
}
// The example displays the following output:
//       IMyInterface Attribute: F9168C5E-CEB2-4faa-B6BF-329BF39FA1E4
//       myGuid1 equals myGuid2
//       myGuid1 == myGuid2


Note that the GuidAttribute is typically used in an application to expose a type to COM. If you compile this example, you can run Regasm.exe on the generated assembly to create .reg file and .tlb files. The .reg file can be used to register the coclass in the registry, and the .tlb file can provide metadata for COM interop.

.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

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.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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