Hi ,
I have solved the problem.
ItemID is a unique column in the grid so used that to check whether an additional row is added.
objQM.gvItemDetails.Rows.Cast<DataGridViewRow>().Count(c => c.Cells[7].EditedFormattedValue.ToString() == ItemID) > 0)
one more problem is..Suppose I have added a row to the Form1 datagridview from Form2 by clicking AddItems button ..then Done button.Suppose I wanted to add another row by clicking on the link button in Form1 which takes me to Form2..Now the gridview gets empty and a completely new row is added.So i want to know how if ROW1 is added to Form1 DGV and clicked on DONE button...and again if I want to add another row ROW2.Both Row1 and Row2 shud exist but that is not happening.How to achieve this.