Guid Struct

Definition

Represents a globally unique identifier (GUID).

public value class Guid : IComparable, IComparable<Guid>, IEquatable<Guid>, IFormattable
public value class Guid : IComparable, IComparable<Guid>, IEquatable<Guid>, ISpanFormattable
public value class Guid : IComparable, IComparable<Guid>, IEquatable<Guid>, IParsable<Guid>, ISpanFormattable, ISpanParsable<Guid>
public value class Guid : IComparable, IComparable<Guid>, IEquatable<Guid>, IParsable<Guid>, ISpanFormattable, ISpanParsable<Guid>, IUtf8SpanFormattable
public value class Guid : IComparable, IFormattable
public struct Guid : IComparable, IComparable<Guid>, IEquatable<Guid>, IFormattable
public readonly struct Guid : IComparable, IComparable<Guid>, IEquatable<Guid>, ISpanFormattable
public readonly struct Guid : IComparable, IComparable<Guid>, IEquatable<Guid>, IParsable<Guid>, ISpanFormattable, ISpanParsable<Guid>
public readonly struct Guid : IComparable, IComparable<Guid>, IEquatable<Guid>, IParsable<Guid>, ISpanFormattable, ISpanParsable<Guid>, IUtf8SpanFormattable
[System.Serializable]
public struct Guid : IComparable, IFormattable
[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public struct Guid : IComparable, IComparable<Guid>, IEquatable<Guid>, IFormattable
type Guid = struct
    interface IFormattable
type Guid = struct
    interface ISpanFormattable
    interface IFormattable
type Guid = struct
    interface IFormattable
    interface IParsable<Guid>
    interface ISpanFormattable
    interface ISpanParsable<Guid>
type Guid = struct
    interface IFormattable
    interface IParsable<Guid>
    interface ISpanFormattable
    interface ISpanParsable<Guid>
    interface IUtf8SpanFormattable
[<System.Serializable>]
type Guid = struct
    interface IFormattable
[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type Guid = struct
    interface IFormattable
Public Structure Guid
Implements IComparable, IComparable(Of Guid), IEquatable(Of Guid), IFormattable
Public Structure Guid
Implements IComparable, IComparable(Of Guid), IEquatable(Of Guid), ISpanFormattable
Public Structure Guid
Implements IComparable, IComparable(Of Guid), IEquatable(Of Guid), IParsable(Of Guid), ISpanFormattable, ISpanParsable(Of Guid)
Public Structure Guid
Implements IComparable, IComparable(Of Guid), IEquatable(Of Guid), IParsable(Of Guid), ISpanFormattable, ISpanParsable(Of Guid), IUtf8SpanFormattable
Public Structure Guid
Implements IComparable, IFormattable
Inheritance
Attributes
Implements

Examples

The following example uses the System.Runtime.InteropServices.GuidAttribute class to assign a GUID to an interface and to a user-defined class. 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 namespace System;
using namespace System::Runtime::InteropServices;

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


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

int main()
{
   Attribute^ IMyInterfaceAttribute = Attribute::GetCustomAttribute( IMyInterface::typeid, GuidAttribute::typeid );

   // The Value property of GuidAttribute returns a string. 
   System::Console::WriteLine( String::Concat(  "IMyInterface Attribute: ", (dynamic_cast<GuidAttribute^>(IMyInterfaceAttribute))->Value ) );

   // Using the string to create a guid.
   Guid myGuid1 = Guid(dynamic_cast<GuidAttribute^>(IMyInterfaceAttribute)->Value);

   // Using a byte array to create a guid.
   Guid myGuid2 = 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 not equals 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
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));

        System.Console.WriteLine("IMyInterface Attribute: " + IMyInterfaceAttribute.Value );

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

        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
open System
open System.Runtime.InteropServices

// Guid for the interface IMyInterface.
[<Guid "F9168C5E-CEB2-4faa-B6BF-329BF39FA1E4">]
type IMyInterface =
    abstract MyMethod: unit -> unit

// Guid for the coclass MyTestClass.
[<Guid "936DA01F-9ABD-4d9d-80C7-02AF85C822A8">]
type MyTestClass() =
    interface IMyInterface with
        member _.MyMethod() = ()

let IMyInterfaceAttribute = 
    Attribute.GetCustomAttribute(typeof<IMyInterface>, typeof<GuidAttribute>) :?> GuidAttribute

printfn $"IMyInterface Attribute: {IMyInterfaceAttribute.Value}"

// Use the string to create a guid.
let myGuid1 = Guid IMyInterfaceAttribute.Value
// Use a byte array to create a guid.
let myGuid2 = Guid(myGuid1.ToByteArray())

if myGuid1.Equals myGuid2 then
    printfn "myGuid1 equals myGuid2"
else
    printfn "myGuid1 does not equal myGuid2"

// Equality operator can also be used to determine if two guids have same value.
if myGuid1 = myGuid2 then
    printfn "myGuid1 == myGuid2"
else
    printfn "myGuid1 <> myGuid2"

// The example displays the following output:
//       IMyInterface Attribute: F9168C5E-CEB2-4faa-B6BF-329BF39FA1E4
//       myGuid1 equals myGuid2
//       myGuid1 == myGuid2
Imports System.Runtime.InteropServices

' Guid for the interface IMyInterface.
<Guid("F9168C5E-CEB2-4faa-B6BF-329BF39FA1E4")> _
Interface IMyInterface
    Sub MyMethod()
End Interface

' Guid for the coclass MyTestClass.
<Guid("936DA01F-9ABD-4d9d-80C7-02AF85C822A8")> _
Public Class MyTestClass
    Implements IMyInterface

    Public Sub MyMethod() Implements IMyInterface.MyMethod
    End Sub

    Public Shared Sub Main()
        Dim IMyInterfaceAttribute As GuidAttribute = CType(Attribute.GetCustomAttribute(GetType(IMyInterface), GetType(GuidAttribute)),
                                                           GuidAttribute)

        Console.WriteLine("IMyInterface Attribute: " + IMyInterfaceAttribute.Value)

        ' Use the string to create a guid.
        Dim myGuid1 As New Guid(IMyInterfaceAttribute.Value)
        ' Use a byte array to create a guid.
        Dim myGuid2 As New Guid(myGuid1.ToByteArray())

        If myGuid1.Equals(myGuid2) Then
            Console.WriteLine("myGuid1 equals myGuid2")
        Else
            Console.WriteLine("myGuid1 does not equal myGuid2")
        End If 

        ' The equality operator can also be used to determine if two guids have same value.
        If myGuid1.ToString() = myGuid2.ToString() Then
            Console.WriteLine("myGuid1 == myGuid2")
        Else
            Console.WriteLine("myGuid1 != myGuid2")
        End If
    End Sub
End Class
' The example displays the following output:
'       IMyInterface Attribute: F9168C5E-CEB2-4faa-B6BF-329BF39FA1E4
'       myGuid1 equals myGuid2
'       myGuid1 == myGuid2

Note that the GuidAttribute attribute is typically used in an application to expose a type to COM. If you compile this example, you can run the Assembly Registration tool (Regasm.exe) on the generated assembly to create registry (.reg) and type library (.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.

Remarks

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.

Constructors

Guid(Byte[])

Initializes a new instance of the Guid structure by using the specified array of bytes.

Guid(Int32, Int16, Int16, Byte, Byte, Byte, Byte, Byte, Byte, Byte, Byte)

Initializes a new instance of the Guid structure by using the specified integers and bytes.

Guid(Int32, Int16, Int16, Byte[])

Initializes a new instance of the Guid structure by using the specified integers and byte array.

Guid(ReadOnlySpan<Byte>)

Initializes a new instance of the Guid structure by using the value represented by the specified read-only span of bytes.

Guid(ReadOnlySpan<Byte>, Boolean)
Guid(String)

Initializes a new instance of the Guid structure by using the value represented by the specified string.

Guid(UInt32, UInt16, UInt16, Byte, Byte, Byte, Byte, Byte, Byte, Byte, Byte)

Initializes a new instance of the Guid structure by using the specified unsigned integers and bytes.

Fields

Empty

A read-only instance of the Guid structure whose value is all zeros.

Methods

CompareTo(Guid)

Compares this instance to a specified Guid object and returns an indication of their relative values.

CompareTo(Object)

Compares this instance to a specified object and returns an indication of their relative values.

Equals(Guid)

Returns a value indicating whether this instance and a specified Guid object represent the same value.

Equals(Object)

Returns a value that indicates whether this instance is equal to a specified object.

GetHashCode()

Returns the hash code for this instance.

NewGuid()

Initializes a new instance of the Guid structure.

Parse(ReadOnlySpan<Char>)

Converts a read-only character span that represents a GUID to the equivalent Guid structure.

Parse(ReadOnlySpan<Char>, IFormatProvider)

Parses a span of characters into a value.

Parse(String)

Converts the string representation of a GUID to the equivalent Guid structure.

Parse(String, IFormatProvider)

Parses a string into a value.

ParseExact(ReadOnlySpan<Char>, ReadOnlySpan<Char>)

Converts the character span representation of a GUID to the equivalent Guid structure, provided that the string is in the specified format.

ParseExact(String, String)

Converts the string representation of a GUID to the equivalent Guid structure, provided that the string is in the specified format.

ToByteArray()

Returns a 16-element byte array that contains the value of this instance.

ToByteArray(Boolean)
ToString()

Returns a string representation of the value of this instance in registry format.

ToString(String)

Returns a string representation of the value of this Guid instance, according to the provided format specifier.

ToString(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.

TryFormat(Span<Byte>, Int32, ReadOnlySpan<Char>)
TryFormat(Span<Char>, Int32, ReadOnlySpan<Char>)

Tries to format the current GUID instance into the provided character span.

TryParse(ReadOnlySpan<Char>, Guid)

Converts the specified read-only span of characters containing the representation of a GUID to the equivalent Guid structure.

TryParse(ReadOnlySpan<Char>, IFormatProvider, Guid)

Tries to parse a span of characters into a value.

TryParse(String, Guid)

Converts the string representation of a GUID to the equivalent Guid structure.

TryParse(String, IFormatProvider, Guid)

Tries to parse a string into a value.

TryParseExact(ReadOnlySpan<Char>, ReadOnlySpan<Char>, Guid)

Converts span of characters representing the GUID to the equivalent Guid structure, provided that the string is in the specified format.

TryParseExact(String, String, Guid)

Converts the string representation of a GUID to the equivalent Guid structure, provided that the string is in the specified format.

TryWriteBytes(Span<Byte>)

Tries to write the current GUID instance into a span of bytes.

TryWriteBytes(Span<Byte>, Boolean, Int32)

Operators

Equality(Guid, Guid)

Indicates whether the values of two specified Guid objects are equal.

GreaterThan(Guid, Guid)

Compares two values to determine which is greater.

GreaterThanOrEqual(Guid, Guid)

Compares two values to determine which is greater or equal.

Inequality(Guid, Guid)

Indicates whether the values of two specified Guid objects are not equal.

LessThan(Guid, Guid)

Compares two values to determine which is less.

LessThanOrEqual(Guid, Guid)

Compares two values to determine which is less or equal.

Explicit Interface Implementations

IComparable.CompareTo(Object)

Compares this instance to a specified Guid object and returns an indication of their relative values.

IFormattable.ToString(String, IFormatProvider)

Returns a string representation of the value of this instance, according to the provided format specifier and culture-specific format information.

ISpanFormattable.TryFormat(Span<Char>, Int32, ReadOnlySpan<Char>, IFormatProvider)

Tries to format the value of the current instance into the provided span of characters.

IUtf8SpanFormattable.TryFormat(Span<Byte>, Int32, ReadOnlySpan<Char>, IFormatProvider)

Tries to format the value of the current instance as UTF-8 into the provided span of bytes.

Applies to