it is my coding for updating textbox value
protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
GridViewRow row = (GridViewRow)GridView1.Rows[e.RowIndex];
TextBox textcategory = (TextBox)row.Cells[2].FindControl("TextBox4");
TextBox textDescription = (TextBox)row.Cells[3].FindControl("TextBox6");
SqlConnection con = new SqlConnection(connection);
con.Open();
SqlCommand cmd = new SqlCommand("update Category set Description='" + textDescription.Text + "' where categoryName='" + textcategory.Text + "'", con);
cmd.ExecuteNonQuery();
con.Close();
GridView1.EditIndex = -1;
Bindgrid();
}