Forms Data Controls :: Getting Old Values Only In Gridview Update?

I am trying to update a table using gridview. I have dynamically assigned an sqldatasource having update command to it. I am taking values from textbox in edititem template. but problem is textbox doesnt show the new value that i write in it to update the row.

It gives me the old values from the table.

here is some of my code

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
Label lbPatientOID = (Label)GridView1.Rows[e.RowIndex].FindControl("lbPatientOID");
TextBox tbFirstName = (TextBox)GridView1.Rows[e.RowIndex].FindControl("tbFirstName");
TextBox tbLastName = (TextBox)GridView1.Rows[e.RowIndex].FindControl("tbLastName");
sds.UpdateCommand = "UPDATE Patient " +
"SET FirstName=@FirstName, LastName=@LastName " +
"where PatientOID=@PatientOID";
Parameter fname = new Parameter("FirstName");
Parameter lname = new Parameter("LastName");
Parameter pid = new Parameter("PatientOID");
sds.UpdateParameters.Add(fname);
sds.UpdateParameters.Add(lname);
sds.UpdateParameters.Add(pid);
GridView1.DataSource = sds;
GridView1.DataBind();
lbtest.Text = e.Keys.Count.ToString();
}
sds = sqldatasource.