ASP.NET MVC3 Entity Framework Entity not updating correctly

Question

I made a test program for something totally unrelated to Entity Framework and what I thought would be an easy integration turned out to be troublesome. I have a DB Table called "TestEntry" which holds four data fields [ Id (uniqueidentifier), EId (uniqueidentifier), Name, Data ], these are unrelated to any other database tables and are standalone.

The issue is a simple update which is defined as such:

    EDMEntities _db = new EDMEntities();

    public List<TestEntry> GetEntities()
    {
        return _db.TestEntries.ToList();
    }
    public void EditEntry(TestEntry newEntry)
    {
        TestEntry entry = _db.TestEntries.FirstOrDefault(e => e.Id == newEntry.Id);
        if (string.IsNullOrEmpty(newEntry.Name)) { entry.Name = newEntry.Name; }
        if (string.IsNullOrEmpty(newEntry.Data)) { entry.Data = newEntry.Data; }

        if (entry.EntityState == System.Data.EntityState.Modified)
        {
            _db.SaveChanges();
        }
    }

After stepping through it I noticed:

Neither entry.Name nor entry.Data gets updated with the values from newEntry
The EntityState remains unchanged thus not entering the conditional

Any ideas on what this could be?

Scott Munro · Accepted Answer · 2011-08-16 11:59:59Z

2

You need to negate the conditionals.

if (!string.IsNullOrEmpty(newEntry.Name))

Note the exclamation mark.

answered Aug 16, 2011 at 11:59

Scott Munro

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3 Comments

Cosmin Pârvulescu Over a year ago

Do you mean entry.EntityState != System.Data.EntityState.Modified as that would still not yield any results because the actual entity does not get updated.

Scott Munro Over a year ago

@Cosmin Parculescu: No. Where you are checking if the newEntity has values is the problem.

Scott Munro Over a year ago

Sometimes it just takes a fresh pair of eyes to catch them.

Ladislav Mrnka · Accepted Answer · 2011-08-16 12:01:20Z

2

Shouldn't it be:

if (!string.IsNullOrEmpty(newEntry.Name)) { entry.Name = newEntry.Name; }
if (!string.IsNullOrEmpty(newEntry.Data)) { entry.Data = newEntry.Data; }

answered Aug 16, 2011 at 12:01

Ladislav Mrnka

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