filter data of dataset / datatable

ds.Tables[0].Select("Name LIKE %" + "abc%" );
------------------------------
DataView dv = ds.Tables[0].DefaultView;
dv.RowFilter = "lastname like '" + txtName.Text + "%'";
DataTable dt = dv.ToTable();
------------------------------
if (((DataRow[])dt.Select("dname="+newdnam)).Length > 0)
---------------------------------------------------------------
DataTable dt = (DataTable)Session["data"];
DataRow[] drow = dt.Select("id="+id+"");
Label1.Text = drow[0].ItemArray[1].ToString();
---------------------------------------------------------------
dt.Constraints.Clear();
dt.PrimaryKey = newDataColumn[] { dt.Columns["id"] };DataRow[] dr = dt.Rows.Find(val.ToString());