Updating a record using a class object with Entity Framework in C#

Question

I have an entity class which includes many fields. To make it simple, let's assume the class is defined as following:

public partial class Branches
{

    public int num { get; set; }
    public string name { get; set; }
    public string street { get; set; }
    public string city { get; set; }

In my API class, I want to define a function for updating a record of this type. As creating a function to update each field separately seems like quite an overhead for my application, I decided to define one function that updates all fields. Can I assign the object received by the function directly to the object used for the update as following?

void updateBranch(Branches branch)
{
  using (var dbContext = new entitiesContext())
  {
    var result = dbContext.Branches.SingleOrDefault(b => b.num == branch.num);                                                
    if (result != null)
    {
      **result = branch;**                        
      dbContext.SaveChanges();
    }
  }
}

I'm using Entity Framework version 6.0

"many fields". I'm not sure if you should set the whole entity to Modified, see this: stackoverflow.com/a/30824229/861716 — Gert Arnold
– Gert Arnold, Commented Jun 13, 2015 at 22:47

Marc Cals · Accepted Answer · 2015-06-13 20:39:37Z

2

Yes you can use it, with the following code

void updateBranch(Branches branch)
{
    using (var dbContext = new entitiesContext())
    {
        dbContext.Branches.Attach(branch);
        dbContext.Entry(branch).State = EntityState.Modified;              
        dbContext.SaveChanges();
    }
}

When you attach a Entity to DBContext, Entity Framework is aware that this instance exist in database and will perform an update operation.

edited Jun 13, 2015 at 20:39

answered Jun 13, 2015 at 12:11

Marc Cals

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3 Comments

user648479 Over a year ago

This causes an error saying that the lambda expression is not a delegate type.

user648479 Over a year ago

sorry, still not working :( I see the original record without the modifications

Marc Cals Over a year ago

Try now! without modified EF thought that nothing was changed in the object!

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