ASP.NET MVC3 Code-First Error- attempting to update entity

Question

I\'ve checked this question and it seems to be related to what I need, but does not answer it exactly.

I have an entity (Sql Compact using EF Code First via MVC3- if

Answer 1

The short answer is that you've already loaded the entity into the context with the Find and you cannot later attach another one.

You are left with two options:

• Detach the first instance, then attach the second
• Copy the fields from the second instance to the first

I'll share code for the first option. First, add a Detach method to your DbContext implementation:

public void Detach(object entity)
{
    var objectContext = ((IObjectContextAdapter)this).ObjectContext;
    objectContext.Detach(entity);
}

Then call Detach instead of setting the variable to null

var startingIssue = db.Issues.Find(issue.IssueId);
if (ModelState.IsValid)
{
    if (issue.CreatedBy != startingIssue.CreatedBy) issue.CreatedBy = startingIssue.CreatedBy;
    if (issue.CreatedDate != startingIssue.CreatedDate) issue.CreatedDate = startingIssue.CreatedDate;
    issue.LastActivity = (DateTime?)DateTime.Now.Date;
    if (issue.ClosedBy != null) issue.ClosedDate = (DateTime?)DateTime.Now.Date;

    // startingIssue = null;
    db.Detach(startingIssue);

    db.Entry(issue).State = EntityState.Modified;
    db.SaveChanges();
    return RedirectToAction("Index");
}