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Why is a newly created EF object throwing an id is an exception when trying to save?

I am trying to implement the entity framework included in VS2010 but ran into a problem with my database / model generated from the GUI.

When I do this:

user = dataset.UserSet.CreateObject();
user.Id = Guid.NewGuid();
dataset.UserSet.AddObject(user);
dataset.SaveChanges();

{"Cannot insert NULL value in column" Identity ", table" BarSoc2.dbo.UserSet ", column does not allow null values. INSERT does not work. \ R \ nApplication completed." }

The insert of the table you are entering looks like this:

-- Creating table 'UserSet'
CREATE TABLE [dbo].[UserSet] (
    [Id] uniqueidentifier  NOT NULL,
    [Name] nvarchar(max)  NOT NULL,
    [Username] nvarchar(max)  NOT NULL,
    [Password] nvarchar(max)  NOT NULL
);
GO

-- Creating primary key on [Id] in table 'UserSet'
ALTER TABLE [dbo].[UserSet]
ADD CONSTRAINT [PK_UserSet]
    PRIMARY KEY CLUSTERED ([Id] ASC);
GO

Am I creating the object differently or am I doing something else wrong?

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2 answers


You don't need to set the ID property manually. It should be installed automatically on save. I am assuming you are using the default template for the Entity Framework, not the Self-tracking entity template or the POCOs template. If so, then something along the following lines would seem more appropriate:



User user = new User();
dataset.AddToUsers(user);
dataset.SaveChanges();
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In the model, for fields that are defined as key, add the following attribute. This key, which is not marked as IDENTITY in the database, Entity Framework throws an exception



[Key]
[Display(Name = "Id")]     
[DatabaseGenerated(System.ComponentModel.DataAnnotations.DatabaseGeneratedOption.None)]
public int Id { get; set; }
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