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Guid Structure

Represents a globally unique identifier (GUID).

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

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

The Guid type exposes the following members.

  NameDescription
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360Guid(Byte[])Initializes a new instance of the Guid class using the specified array of bytes.
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360Guid(String)Initializes a new instance of the Guid class using the value represented by the specified string.
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360Guid(Int32, Int16, Int16, Byte[])Initializes a new instance of the Guid class using the specified integers and byte array.
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360Guid(Int32, Int16, Int16, Byte, Byte, Byte, Byte, Byte, Byte, Byte, Byte)Initializes a new instance of the Guid class using the specified integers and bytes.
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  NameDescription
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360CompareTo(Guid)Compares this instance to a specified Guid object and returns an indication of their relative values.
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360CompareTo(Object)Compares this instance to a specified object and returns an indication of their relative values.
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360Equals(Guid)Returns a value indicating whether this instance and a specified Guid object represent the same value.
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360Equals(Object)Returns a value indicating whether this instance is equal to a specified object. (Overrides ValueType.Equals(Object).)
Protected methodSupported by Silverlight for Windows PhoneSupported by Xbox 360FinalizeAllows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360GetHashCodeReturns the hash code for this instance. (Overrides ValueType.GetHashCode().)
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360GetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodSupported by Silverlight for Windows PhoneSupported by Xbox 360MemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodStatic memberSupported by Silverlight for Windows PhoneSupported by Xbox 360NewGuidInitializes a new instance of the Guid class.
Public methodStatic memberSupported by Silverlight for Windows PhoneParseConverts the string representation of a GUID to the equivalent Guid value.
Public methodStatic memberSupported by Silverlight for Windows PhoneParseExactConverts the string representation of a GUID to the equivalent Guid value, provided that the string is in the specified format.
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360ToByteArrayReturns a 16-element byte array that contains the value of this instance.
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360ToString()Returns a String representation of the value of this instance in registry format. (Overrides ValueType.ToString().)
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360ToString(String)Returns a String representation of the value of this Guid instance, according to the provided format specifier.
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360ToString(String, IFormatProvider)Returns a String representation of the value of this instance of the Guid class, according to the provided format specifier and culture-specific format information.
Public methodStatic memberSupported by Silverlight for Windows PhoneTryParseConverts the string representation of a GUID to the equivalent Guid value.
Public methodStatic memberSupported by Silverlight for Windows PhoneTryParseExactConverts the string representation of a GUID to the equivalent Guid value, provided that the string is in the specified format.
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  NameDescription
Public operatorStatic memberSupported by Silverlight for Windows PhoneSupported by Xbox 360EqualityIndicates whether the values of two specified Guid objects are equal.
Public operatorStatic memberSupported by Silverlight for Windows PhoneSupported by Xbox 360InequalityReturns an indication whether the values of two specified Guid objects are not equal.
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  NameDescription
Public fieldStatic memberSupported by Silverlight for Windows PhoneSupported by Xbox 360EmptyA read-only instance of the Guid class whose value is guaranteed to be all zeroes.
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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 GuidAttribute class to assign a GUID to a user-defined class and an interface. It retrieves the value of the GUID by calling the Attribute.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 MyTestClass.
[Guid("936DA01F-9ABD-4d9d-80C7-02AF85C822A8")]
public class Example : IMyInterface
{
   public void MyMethod() { }

   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      Attribute IMyInterfaceAttribute = Attribute.GetCustomAttribute(typeof(IMyInterface), typeof(GuidAttribute));

      // The Value property of GuidAttribute returns a string. 
      outputBlock.Text += "IMyInterface Attribute: " + ((GuidAttribute)IMyInterfaceAttribute).Value + "\n";

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

      // Equals is overridden and so value comparison is done though references are different.
      if (myGuid1.Equals(myGuid2))
         outputBlock.Text += "myGuid1 equals myGuid2" + "\n";
      else
         outputBlock.Text += "myGuid1 not equals myGuid2" + "\n";

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


Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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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