What's the use of BeginEdit/EndEdit when used with a datarow
                            
                         
                        
                     
                 
                
                    1.What's the use of BeginEdit/EndEdit when used with a datarow
2. When a datarow variable needs to be created, e.g. 
DataRow dr=new DataRow();
It gives the error:"No overload for method 'DataRow' takes '0' arguments"
Why such error. If I simply use Datarow dr, then no error.
3. Will the find method work on table having primary key? I mean if there is no primary key, then how to find the record?
4. When I write 
                                               DataRow dr;
			int aa=Int32.Parse(textBox1.Text);
			dr=ds.Tables[0].Rows.Find(aa);
It gives run time error that table has no primary key, though it is present.
5. What's the syntax to retrieve a particular value of a field of a row using datarow.