Why is this code not working?

```
        (this.namesBindingSource.Current as DataRowView).Delete();         
        this.namesTableAdapter.Update(database1DataSet1);

```

Error : 
Update requires a valid DeleteCommand when passed DataRow collection with deleted rows.

Database is service-based database added to project with only one table which is show in dataGridView and this code is linked to button. You will click on row for delete and then pres button and get error....

What is wrong? I'm getting crazy......