帮我看看这个操作数据的修改字段问题

不能修改数据库的数据？请指点下哪错了？
//修改银行用户名和密码方法
        //这里有错，请指点
        private void btnModify_Click(object sender, System.EventArgs e)
        {
            string cardId = this.cboCardId.Text;
            string userName = this.txtUserName.Text.Trim();
            string pwd = this.txtPassword.Text.Trim();
    
            try
            {
                
                this.sqlAdapter = new SqlDataAdapter("select * from BankInfo",this.sqlConn);
                dataSet = new DataSet();
                this.sqlAdapter.Fill(dataSet,"BankInfo");

                this.sqlAdapter.UpdateCommand = new SqlCommand("update BankInfo set UserName = '"+ userName +"',password = '"+ pwd +"' where CardId = '"+ cardId +"'",this.sqlConn);
                this.sqlAdapter.Update(this.dataSet,"BankInfo");
                MessageBox.Show("修改成功");
                this.ClearFields();
                this.dataGrid1.Update();

            }
            catch(SqlException ex)
            {
                MessageBox.Show(ex.Message);
            }
            catch(Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                this.sqlConn.Close();
            }
                        
        }