ADO.NET中的多数据表操作之读取

开发者在线 Builder.com.cn 更新时间:2007-11-13作者:郑佐 来源:csdn

二.填充数据集

  建立一个窗体程序来演示实际的操作,界面如下:


图2-1

  整个应用程序就是一个Form,上面的三个DataGrid分别用来显示相关表的数据,不过他们是互动的。另外的两个单选框用来决定更新数据的方式,两个按钮正如他们的名称来完成相应的功能。

  这里我们用一个DataAdapter来完成数据集的填充,执行的存储过程如下:

CREATE PROCEDURE GetCustomerOrdersInfo

AS

SELECT CustomerID,CompanyName,ContactName FROM Customers WHERE CustomerID LIKE 'A%'

SELECT OrderID,OrderDate,CustomerID FROM Orders WHERE CustomerID IN
(SELECT CustomerID FROM Customers WHERE CustomerID LIKE 'A%')

SELECT OrderID,ProductID,UnitPrice,Quantity,Discount FROM [Order Details] WHERE OrderID IN
(SELECT OrderID FROM Orders WHERE CustomerID IN
(SELECT CustomerID FROM Customers WHERE CustomerID LIKE 'A%'))

GO

  为了减少数据量,这里只取了CustomerID以’A’开头的数据。建立DataAccess类来管理窗体同数据层的交互:

using System;
using System.Data;
using System.Data.SqlClient;
using Microsoft.ApplicationBlocks.Data;
namespace WinformTest
{
 public class DataAccess
 {
  private string _connstring = "data source=(local);initial catalog=Northwind;uid=csharp;pwd=c#.net2004;";
  private SqlConnection _conn;
  ///构造函数
  public DataAccess()
  {
   _conn = new SqlConnection(_connstring);
  }

  下面的函数完成单个数据适配器来完成数据集的填充,

public void FillCustomerOrdersInfo(DatasetOrders ds)
{
 SqlCommand comm = new SqlCommand("GetCustomerOrdersInfo",_conn);
 comm.CommandType = CommandType.StoredProcedure;
 SqlDataAdapter dataAdapter = new SqlDataAdapter(comm);
 dataAdapter.TableMappings.Add("Table","Customers");
 dataAdapter.TableMappings.Add("Table1","Orders");
 dataAdapter.TableMappings.Add("Table2","Order Details");
 dataAdapter.Fill(ds);
}


  如果使用SqlHelper来填充那就更简单了:

public void FillCustomerOrdersInfoWithSqlHelper(DatasetOrders ds)
{
SqlHelper.FillDataset(_connstring,CommandType.StoredProcedure,"GetCustomerOrdersInfo",ds,new string[]{"Customers","Orders","Order Details"});
}

用户评论

  • 用户名
  • 评论内容