Entity Framework error: Cannot insert explicit value for identity column in table

I'm getting this error on EF.

Cannot insert explicit value for identity column in table 'GroupMembers_New' when IDENTITY_INSERT is set to OFF.

The column on the Db is identity increment and on the EF design file, StoreGeneratedPattern is identity as well. Seems like EF is trying to insert 0 every time I try to save.

Some suggestions says ID is reserved on tables or drop the table and rerun the scripts.

Any ideas?

Here's some code:

GroupMember groupMember = new GroupMember();
            groupMember.GroupId = group.Id;
            groupMember.UserId = (new UserId(group.Owner));
            //groupMember.Id = _groupContext.GroupMembers.Count();
            group.GroupMembers.Add(groupMember);

            _groupContext.SaveChanges();

Solution 1:

I have run into this before. This error means you are trying to assign a value explicitly to a column where the database automatically assigns it.

Suggestion: Update your edmx file to reflect any changes you may have made in the database. If the database automatically assigns the value, you should see the "IsDbGenerated=true" attribute in your designer file under that property. If it's not there, you can add it manually.

Solution 2:

Try this:

using System.ComponentModel.DataAnnotations.Schema;
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public decimal Identity_Col { get; set; }

The Entity Framework class file adds these lines of code to the Identity column.

Solution 3:

Put these attribs on top of the property which is identity:

[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int ID { get; set; }

Solution 4:

EF Code first: Because of an auto-increment PK 'id' field AND a guid column, design like this:

[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid FileToken { get; set; }

there was a duplicate identity. I changed it to:

[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
[DefaultValue("newid()")]
public Guid FileToken { get; set; }

and the problem went away.