cannot read the data from gridview column

Hi friends the following is my code for read the cell value from gridview. when i read it return null for cell value. but gridview has the value for the particular cell.

public bool inserstumark(Commonpropertis comp, System.Web.UI.WebControls.GridView grid)

{

bool result = false;

if (comp.EXAMNAMES != "Annual Exam" || comp.EXAMNAMES!="Half yearly Exam"|| comp.EXAMNAMES!="Quartely Exam" )

{

int rows = grid.Rows.Count;

for (int i = 0; i < rows; i++)

{

// comp.ADMISSIONNUMBER = Convert.ToInt32(grid.Rows[i].Cells[0].Text);

System.Web.UI.WebControls.Label lbl = grid.Rows[i].FindControl("lblrollno") as System.Web.UI.WebControls.Label;

comp.ROLLNUMBER = lbl.Text;

// comp.NAME = grid.Rows[i].Cells[2].Text;

System.Web.UI.WebControls.TextBox txt = grid.Rows[i].FindControl("mark2txt") as System.Web.UI.WebControls.TextBox;

comp.EXTERNALMARK =Convert.ToInt32(txt.Text);

result= userdao.inserstumark1(comp);

}

return result;

}