performing search on dataset windows from using c#

Question

hi

i need to perform a search on a table in the dataset, my code performs the search for the first time only and diplay the result in couple of text boxes placed on the form, but when i try to repeat the search if does not responding at all and nothing happens,

it does not even got stuck..

my code is

string str_search = "SELECT * FROM EMPDETAILS WHERE EMPID= '" + txtItemSearch.Text + "'";
           
            da.SelectCommand = new SqlCommand(str_search, conn);
            da.Fill(payRullDataSet, "EmpDetails");
            DataTable dt = payRullDataSet.Tables["EmpDetails"];
            txtID.Text = dt.Rows[0]["EMPID"].ToString();



this is it ..

any ideas can help ?..:)