C# how to create a Guid value?

Question

One field of our struct is Guid type. How to generate a valid value for it?

Onine you can use this https://devtoolsonline20190908040816.azurewebsites.net/DevTools/GuidGenerator — GomuGomuNoRocket, Sep 11 '19 at 11:45

score 1098 · Accepted Answer · answered Feb 26 '10 at 19:02

1098

Guid id = Guid.NewGuid();

answered Feb 26 '10 at 19:02

David

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If you, like me, make the mistake of doing (new Guid().toString()) you will get 0000-00000-00000-00000. You need to do Guid.NewGuid().toString() – Joao Carlos Jan 03 '15 at 15:10
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You might be interested in formatting Guid too https://msdn.microsoft.com/en-us/library/97af8hh4(v=vs.110).aspx – Anil Vangari Mar 22 '16 at 01:09
14

Little correction, there is no function 'toString()' on Guid object, it is 'ToString()' – A.B. Jun 02 '18 at 11:01

Justin · Answer 2 · 2017-11-30T18:47:47.520

106

There are two ways

var guid = Guid.NewGuid();

or

var guid = Guid.NewGuid().ToString();

both use the Guid class, the first creates a Guid Object, the second a Guid string.

edited Nov 30 '17 at 18:47

answered Feb 26 '10 at 19:09

Justin

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@Justin, That's kind of one way to do it. `var guid = Guid.NewGuid().ToString()` just turns it in to a string. – Michael Meadows Feb 26 '10 at 19:10
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@MichaelMeadows Yes that is correct, the first one creates a new Guid Object, the second creates a string. – Justin Sep 01 '15 at 16:38

score 105 · Answer 3 · edited Feb 01 '18 at 20:09

105

Guid.NewGuid() creates a new random guid.

edited Feb 01 '18 at 20:09

Mariusz Jamro

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answered Feb 26 '10 at 19:02

Adam Driscoll

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score 61 · Answer 4 · answered Feb 26 '10 at 19:03

61

Guid.NewGuid() will create one

answered Feb 26 '10 at 19:03

TWA

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score 37 · Answer 5 · edited Feb 01 '18 at 20:09

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To makes an "empty" all-0 guid like 00000000-0000-0000-0000-000000000000.

var makeAllZeroGuID = new System.Guid();

or

var makeAllZeroGuID = System.Guid.Empty;

To makes an actual guid with a unique value, what you probably want.

var uniqueGuID = System.Guid.NewGuid();

edited Feb 01 '18 at 20:09

Mariusz Jamro

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answered Sep 06 '15 at 05:53

reza.cse08

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score 36 · Answer 6 · 2014-01-16T13:45:13.133

36

var guid = new Guid();

Hey, its a 'valid', although not very useful, Guid.

(the guid is all zeros, if you don't know. Sometimes this is needed to indicate no guid, in cases where you don't want to use a nullable Guid)

edited Jan 16 '14 at 13:45

answered Feb 26 '10 at 19:11

That does not create all zeros. It creates a valid Guid. Guid.Empty returns all zeros. – FlavorScape May 21 '13 at 18:28
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@FlavorScape before you try, I bet you 50 rep (via bounty) you are wrong. Deal? – May 21 '13 at 18:48
meh, i was thinking of Guid.NewGuid(). I really care to verify the new Guid() – FlavorScape May 21 '13 at 21:34
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I beat you by one with this solution: `var guid = new Guid(new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, });` – Jeppe Stig Nielsen Jul 14 '13 at 00:08
@JeppeStigNielsen Never realized that one could create a guid from a byte array. And that's awesome because I'm in need to guidify my hashes! – Konrad Viltersten Aug 15 '16 at 20:34
What cases can you provide where one would use this over a nullable guid? – ComeIn May 14 '19 at 03:36
3

When you must pass a guid to code you don't own that doesn't accept a nullable guid. – May 14 '19 at 13:07

score 32 · Answer 7 · answered Oct 17 '17 at 11:34

32

If you want to create a "desired" Guid you can do

var tempGuid = Guid.Parse("<guidValue>");

where <guidValue> would be something like 1A3B944E-3632-467B-A53A-206305310BAE.

answered Oct 17 '17 at 11:34

Zeliax

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score 22 · Answer 8 · edited Jul 13 '13 at 23:54

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System.Guid desiredGuid = System.Guid.NewGuid();

edited Jul 13 '13 at 23:54

Ahmad

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answered Jul 06 '12 at 11:37

siphab

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This seems to be the new way to do this, as of at least 2012. I don't seem to have Guid.NewGuid() available in 2015. – Dave Yarwood Aug 04 '15 at 20:55
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@DaveYarwood Guid has been under the System namespace for a very long time, and is what every one else is referring to in the other answers (it just happens to be that a new class already has the Using added in for the System Namespace in the normal template) – Stephen Aug 23 '15 at 19:42

score 7 · Answer 9 · answered Dec 06 '19 at 04:52

There's also ShortGuid - A shorter and url friendly GUID class in C#. It's available as a Nuget. More information here.

PM> Install-Package CSharpVitamins.ShortGuid

Usage:

Guid guid = Guid.NewGuid();
ShortGuid sguid1 = guid; // implicitly cast the guid as a shortguid
Console.WriteLine(sguid1);
Console.WriteLine(sguid1.Guid);

This produces a new guid, uses that guid to create a ShortGuid, and displays the two equivalent values in the console. Results would be something along the lines of:

ShortGuid: FEx1sZbSD0ugmgMAF_RGHw 
Guid:      b1754c14-d296-4b0f-a09a-030017f4461f

SAliaMunch · Answer 10 · 2019-08-08T08:24:46.700

1

If you are using this in the Reflection C#, you can get the guid from the property attribute as follows

var propertyAttributes= property.GetCustomAttributes();
foreach(var attribute in propertyAttributes)
{
  var myguid= Guid.Parse(attribute.Id.ToString());
}

edited Aug 08 '19 at 08:24

answered Aug 07 '19 at 12:38

SAliaMunch

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score 1 · Answer 11 · answered Oct 23 '21 at 08:18

It's really easy. The .Net framework provides an in-built function to create and parse GUIDS. This is available in the System namespace and the static Guid class.

To create a GUID just use the code below:

var newGuid = System.Guid.NewGuid();

To parse a GUID string as a GUID, use the code below:

var parsedGuid = System.Guid.Parse(guidString);

If you just want to create a new guide and just use it in your application, just use one of the online GUID Generator tools online to create yourself a new guid.

score 0 · Answer 12 · answered Jan 24 '23 at 18:11

If you are using the ABP framework, it is recommended to use IGuidGenerator.Create() instead of Guid.NewGuid(). This is to ensure GUIDs are sequential, improving read/write times on the database. https://docs.abp.io/en/abp/latest/Guid-Generation#iguidgenerator

C# how to create a Guid value?

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