无提示错误，不能显示数据

PrisidentMain prisidentMain=new PrisidentMain();
                try
                {
                    //connect the database AssociationJSY
                    SqlConnection conn = new SqlConnection(prisidentMain.strconn);
                    prisidentMain.cmd.CommandType = CommandType.Text;
                    prisidentMain.cmd.Connection = conn;

                    prisidentMain.cmd.CommandText = "select * from "+tableName;
                    //open the database
                    conn.Open();
                    prisidentMain.dataset.Clear();

                    prisidentMain.sqlDataAdapter.SelectCommand = prisidentMain.cmd;
                    prisidentMain.sqlDataAdapter.Fill(prisidentMain.dataset,tableName);
                    prisidentMain.BindingSource0.DataSource=prisidentMain.dataset.Tables[tableName];
                    prisidentMain.dataGriShow.DataSource = prisidentMain.BindingSource0;

                    conn.Close();//close the database
                }
                catch (Exception ex) 
                {
                    MessageBox.Show(ex.Message);
                }
            }