how to replace blank text in gridview cell with -- ??

Hello Friends,

I have a gridview with 4 columns , and my 5th column is a template field inside which i have placed a label and 6th is a Select button.

I bind data to my gridview and after that i replace blank spaces with " -- " for proper look.

However, what i get to see is that my template field column although it contains data gets replaced with " -- ". Does any one know why does this happen??
I write following code :

                foreach (GridViewRow row in GridView1.Rows)
                {
                    for (int i = 0; i < row.Cells.Count - 1; i++)
                    {
                        if (row.Cells[i].Text == string.Empty || row.Cells[i].Text == "&nbsp;")
                        {
                            row.Cells[i].Text = "--";
                        }
                    }
                }

Thanks!!!
Happy Coding :)

Best Regards,
Rohan Laghate