'System.Data.Entity.Infrastructure.DbUpdateException' occurred in EntityFramework.dll

c# entity-framework visual-studio wcf

Question

I wrote a rather simple code (client server based on WCF and Windows form). i was trying to update the db so that i could test my code and i encounterd the above exception. Any ideas how to solve it?

      // For testing 
      public void updateTable() 
      {
        using (var db = new overlayDBEntities())
        {
            var overlaydb = new overlayData
            {
                DeviceId = "1111",
                TimestampUTC = new DateTime(1990, 1, 1, 9, 9, 9),
                OverlayData1 = "Random Text"
            };

            db.overlayData.Add(overlaydb);

            try
            {
                db.SaveChanges();
            }
            catch(Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            var overlaydb1 = new overlayData
            {
                DeviceId = "1111",
                TimestampUTC = new DateTime(2000, 2, 2, 10, 10, 10),
                OverlayData1 = "seconed seconed seconed "
            };

            db.overlayData.Add(overlaydb);

            try
            {
                db.SaveChanges();
            }
            catch (Exception ec) 
            {
                Console.WriteLine(ec.Message);
            }
        }
    }
1
6
1/31/2020 10:44:35 AM

Popular Answer

If you need to update Row if already Exists in database so dont use context.Add();you can use as follows.

    var overlaydb1 = new overlayData
    {
      DeviceId = "1111",
      TimestampUTC = new DateTime(2000, 2, 2, 10, 10, 10),
      OverlayData1 = "seconed seconed seconed "
    };

    try
    {
      db.overlayData.Attach(overlaydb1);
      db.ObjectStateManager.ChangeObjectState(overlaydb1, EntityState.Modified);
      db.SaveChanges();
    }

    catch (Exception ec) 
    {
      Console.WriteLine(ec.Message);
    }
2
10/17/2013 11:36:26 AM


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