Use Update Command In Code Behind

 Hi
 I and using gridview. And binding the data in the code behind.
I need to use update command in code behind. How do I achieve this?  I

  protected void lookUP (object sender, EventArgs e)
{
string strSql, strConn;

System.Text.StringBuilder whereClause = new System.Text.StringBuilder();

strConn = ConfigurationManager.ConnectionStrings["drake_CSMConnectionString1"].ConnectionString;

SqlConnection Conn = new SqlConnection(strConn);

if (newClientName.Text != "")
whereClause.Append("'" + newClientName.Text + "'");

strSql = "SELECT * FROM [ftsCSM] where [client_name] = " + whereClause.ToString();

SqlDataAdapter dataAdapter = new SqlDataAdapter(strSql, Conn);

DataSet ds2 = new DataSet();

dataAdapter.Fill(ds2, "ftsCSM");

DataTable dataTable2 = ds2.Tables["ftsCSM"];

int totalRec = dataTable2.Rows.Count;

Clients.DataSource = ds2;
Clients.DataBind();

} // end of lookup()