GridView Cell Color Red If Text Empty?

The following code changes the entire column to Red, however I would like to just change Only cells with empty text.

Q. How can I change Only certain Cells Red and not the entire column?

    protected void gridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            if(e.Row.Cells[7].Text.Contains(""))
                e.Row.Cells[7].BackColor = System.Drawing.Color.Red;
        }
    }