win常规操作.docx

1. DBHelper类class DBHelper String connstr = Data Source=.;Initial Catalog=FlowerSys;User ID=sa; SqlConnection conn; /封装数据库对象 public SqlConnection Conn get if (conn = null) conn = new SqlConnection(connstr); return conn; /打开数据库连接 public void OpenConn() if (Conn.State = ConnectionState.Broken) Conn.Close(); Conn.Open(); else if (Conn.State = ConnectionState.Closed) Conn.Open(); /关闭数据库连接 public void CloseConn() if (Conn.State = ConnectionState.Broken | Conn.State = ConnectionState.Open) Conn.Close(); 2. 连接式 增，删，改/sql代码使用string.Format()方法组合出。 string sql = string.Format(update FlowerSale set SaleCount=0,SalePrice=1, Remark=2 where SaleId=3, txtCount.Text.Trim(), txtPrice.Text.Trim(), txtRemark.Text.Trim(), Id); try db.OpenConn();/连接数据库 /生成Command对象将sql语句和连接对象传入 SqlCommand comm = new SqlCommand(sql, db.Conn); /调用ExecuteNonQuery()方法执行sql操作并返回受影响的行数 int num = comm.ExecuteNonQuery(); if (num = 1) MessageBox.Show(更新成功！); else MessageBox.Show(更新失败！); catch (Exception ex) MessageBox.Show(ex.Message);/发生异常时显示错误信息 finally db.CloseConn();/关闭数据库连接 this.Close();/更新完之后关闭3. 连接式 查询操作string sql = select fs.SaleId,fs.SaleCount,fs.SalePrice,fs.Remark from FlowerSale as fs where fs.SaleId= + Id; SqlDataReader reader = null;/声明一个对象用来保存查询结果 try db.OpenConn();/打开连接 SqlCommand comm = new SqlCommand(sql, db.Conn); /查询操作使用ExecuteReader()方法，注意返回结果为SqlDataReader类型 reader = comm.ExecuteReader(); /循环获取查询内容 while (reader.Read() lblNo.Text = readerSaleId.ToString(); txtCount.Text = readerSaleCount.ToString(); txtPrice.Text = readerSalePrice.ToString(); txtRemark.Text = readerRemark.ToString(); catch (Exception ex) /发生异常时显示错误信息 MessageBox.Show(ex.Message); finally reader.Close();/关闭SqlDataReader。 db.CloseConn();/关闭连接 4. 非空验证foreach (Control item in this.Controls) if (item is TextBox) if (item.Text.Trim() = string.Empty) MessageBox.Show(请输入所有手机信息); return; 5. 断开式 comboBox数据绑定/查询语句 String sql = select * from MobileBrand; SqlDataAdapter sda = new SqlDataAdapter(sql, db.Conn); if (ds.TablesMobileBrand != null) ds.TablesMobileBrand.Clear(); sda.Fill(ds, MobileBrand); /在上表中第一行添加一行 DataRow row = ds.TablesMobileBrand.NewRow();/新建数据行，创建格式 row0 = 0; row1 = 请选择; ds.TablesMobileBrand.Rows.InsertAt(row,0); /绑定comboBox控件 cboBrand.DataSource = ds.TablesMobileBrand; cboBrand.ValueMember = BrandId; cboBrand.DisplayMember = Brand;6. 断开式 dataGridViews数据绑定 /查询语句string sql = select fs.SaleId,f.FlowerId,f.FlowerName,fs.SaleCount,fs.SalePrice,fs.SaleDate,fs.SaleClert,fs.Remark from FlowerSale as fs inner join Flower as f on (fs.FlowerId=f.FlowerId); /SqlDataAdapter对象负责执行sql语句并得到结果 SqlDataAdapter sda = new SqlDataAdapter(sql, db.Conn); /先判断表是否存在，存在是否为空，清空操作 if (ds.TablesFlower != null) ds.TablesFlower.Clear(); /将SqlDataAdapter填充数据到DataSet对象中 sda.Fill(ds, Flower); /dataGridView绑定数据表 dgvShow.DataSource = ds.TablesFlower;7. 清空操作foreach (Control item in this.Controls) if (item is TextBox) item.Text = ; 8. 连接式 查询数据绑定ListView控件lvPhone.View = View.Details;/设置listView控件视图为Details lvPhone.Items.Clear();/清空Details视图表中的数据 String sql = select mb.Brand,mi.Type,mi.Price,mi.Size,mi.Weight,mi.Style from MobileInfo mi inner join MobileBrand as mb on(mi.BrandId=mb.BrandId); SqlDataReader reader = null; try db.OpenConn(); SqlCommand comm = new SqlCommand(sql, db.Conn); reader = comm.ExecuteReader(); while (reader.Read() /声明一个listView行，将读取出的数据按行添加入listView行 ListViewItem item = new ListViewItem(readerBrand.ToString(), 0); item.SubItems.Add(readerType.ToString(); item.SubItems.Add(readerPrice.ToString(); item.SubItems.Add(readerSize.ToString(); item.SubItems.Add(readerWeight.ToString