CODEWITHSUNDEEP
c#entity-frameworkdbcontext
Masoud
Masoud

Reputation: 8171

Error in updating single property of an entity using Entity Framework

I have following Entity:

public class Document
{
   public int Id { get; set; }
   [Required]
   public string Number { get; set; }
   public int Version { get; set; }
   //other properties with [Required]
}

I wrote a method to update only Version of one Document:

public void SetDocumentVersion(int docId, int version)
{
   var doc = new Document() { Id = docId, Version= version };
   using (var db = new MyEfContextName())
   {
     db.Documents.Attach(doc);
     db.Entry(doc).Property(x => x.Version).IsModified = true;
     db.SaveChanges();   //<--- get error
}

}

But when I run the method I get following Error:

The Number field is required.

Is there any way to bypass this validation?

Upvotes: 1

Views: 141

Answers (4)

Prasad Telkikar
Prasad Telkikar

Reputation: 16049

Either remove [Required] attribute to Number property from Document class or assign value to Number property while creating instance of Document class

First approach:

public class Document
{
   public int Id { get; set; }
   //[Required] /*Remove this attribute*/
   public string Number { get; set; }
   public int Version { get; set; }
   //other properties
}

If you can't remove [Required] from model, then assign some value to Number

var doc = new Document() { Id = docId, Version= version, Number = "NotNullStringValue" };

More about required attribute

Upvotes: 0

Evk
Evk

Reputation: 101443

You can disable validation on saving changes like this (do this before calling SaveChanges):

db.Configuration.ValidateOnSaveEnabled = false;

Then it should work as you would expect (generate UPDATE query for just Version column).

Upvotes: 4

garty
garty

Reputation: 416

So, when using Data Annotations on classes that form the tables within your database they are translated into constraints. The Required annotation translates to NOT NULL meaning a value must be supplied.

Remove the Required annotation if you wish the field to be nullable or supply a value.

https://msdn.microsoft.com/en-us/library/jj591583(v=vs.113).aspx

Upvotes: 0

user1710989
user1710989

Reputation: 117

Assign a value to the Number field.

var doc = new Document() { Id = docId, Version= version, Number = "SomeValue" };

Upvotes: 0

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