Hi i think instead of this
dtCnsmbl = dsCnsmspplr.Tables[0];
dtCnsmbl.Rows.Clear();
cnsmNm.DataSource = dtCnsmbl;
cnsmNm.DisplayMember = "cnsm_Name";
cnsmNm.ValueMember = "cnsm_Id";
write this
DataTable newdata = dsCnsmspplr.Tables[0].Clone();
cnsmNm.DataSource = newdata;
cnsmNm.DisplayMember = "cnsm_Name";
cnsmNm.ValueMember = "cnsm_Id";