LINQ-to-SQL class doesn't implement INotifyPropertyChanging & INotifyPropertyChanged if pulling from local database

Question

I modified my data source in my LINQ-to-SQL class (by the old delete and drag back in method), and was surprised to see the INotifyPropertyChanging & INotifyPropertyChanged interfaces no longer implemented in the generated classes (MyDb.designer.cs).

The methods for the individual fields went from looking like this...

[Column(Storage="_Size", DbType="NVarChar(100)")]
public string Size
{
    get
    {
        return this._Size;
    }
    set
    {
        if ((this._Size != value))
        {
            this.OnSizeChanging(value);
            this.SendPropertyChanging();
            this._Size = value;
            this.SendPropertyChanged("Size");
            this.OnSizeChanged();
        }
    }
}

To looking like this...

[Column(Storage="_Size", DbType="NVarChar(100)")]
public string Size
{
    get
    {
        return this._Size;
    }
    set
    {
        if ((this._Size != value))
        {
            this._Size = value;
        }
    }
}

Any ideas on why this happens and how it will affect my application?

That's strange. I don't know why it would happen. I do know, though, that without the INotifyPropertyChanged implementation, your DataContext won't be able to track any changes made to those entities. — rossisdead, May 13 '10 at 20:44

score 15 · Accepted Answer · answered Jul 14 '10 at 14:30

15

Make sure your table has a primary key.

answered Jul 14 '10 at 14:30

Marek Stój

4,075
6
49
50

1

For future reference, this is the answer. – Clarence Klopfstein Aug 15 '10 at 00:57
1

For bonus points do you know why it needs to have a primary key? – Slugart Dec 13 '14 at 10:38
1

I reach here by searching around. and the exact problem is why a primary key is necessary? – Jason Hu Sep 01 '15 at 15:16

score 5 · Answer 2 · answered May 13 '10 at 20:58

5

Check to make sure you did not set ObjectTrackingEnabled = false; or that you did not turn it off on the designer surface.

answered May 13 '10 at 20:58

Adam

3,014
5
33
59

score 1 · Answer 3 · answered Jan 27 '11 at 11:49

1

Adding primary key will resolve the problem.

answered Jan 27 '11 at 11:49

Greatran

180
3
18

score 0 · Answer 4 · answered May 13 '10 at 20:46

0

Did you change something in the designer after drag and drop? IIRC, there is a tracked property or some such.

answered May 13 '10 at 20:46

John Buchanan

5,054
2
19
17

LINQ-to-SQL class doesn't implement INotifyPropertyChanging & INotifyPropertyChanged if pulling from local database

4 Answers4

Linked