[原创]Silverlight与Access数据库的互操作(CURD完全解析)

Silverlight与SQL Server或SQL Server Express的互操作，已成为我们常见的开发Siverlight应用程序的一种模式。可是在开发一些小型应用程序时，我们就需要使用一些小巧的轻量级的数据库，比如Access数据库。由于Visual Studio中并没有直接提供Silverlight与Access互操作的系列方法。于是本文就将为大家介绍如何让Silverlight使用Access作为后台数据库。

准备工作

1）建立起测试项目

细节详情请见强大的DataGrid组件[2]_数据交互之ADO.NET Entity Framework——Silverlight学习笔记[10]。

2）创建测试用数据库

如下图所示，创建一个名为Employees.mdb的Access数据库，建立数据表名称为Employee。将该数据库置于作为服务端的项目文件夹下的App_Data文件夹中，便于操作管理。



建立数据模型

EmployeeModel.cs文件（放置在服务端项目文件夹下）

using System;

using System.Collections.Generic;

using System.Linq;

namespace datagridnaccessdb

{

public class EmployeeModel

{

public int EmployeeID { get; set; }

public string EmployeeName { get; set; }

public int EmployeeAge { get; set; }

}

}

建立服务端Web Service★

右击服务端项目文件夹，选择Add->New Item....，按下图所示建立一个名为EmployeesInfoWebService.asmx的Web Service，作为Silverlight与Access数据库互操作的桥梁。



创建完毕后，双击EmployeesInfoWebService.asmx打开该文件。将里面的内容修改如下：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Services;

using System.Data.OleDb;//引入该命名空间为了操作Access数据库

using System.Data;

namespace datagridnaccessdb

{

/// <summary>

/// Summary description for EmployeesInfoWebService

/// </summary>

[WebService(Namespace = "http://tempuri.org/")]

[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]

[System.ComponentModel.ToolboxItem(false)]

// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.

// [System.Web.Script.Services.ScriptService]

public class EmployeesInfoWebService : System.Web.Services.WebService

{

[WebMethod]//获取雇员信息

public List<EmployeeModel> GetEmployeesInfo()

{

List<EmployeeModel> returnedValue = new List<EmployeeModel>();

OleDbCommand Cmd = new OleDbCommand();

SQLExcute("SELECT * FROM Employee", Cmd);

OleDbDataAdapter EmployeeAdapter = new OleDbDataAdapter();

EmployeeAdapter.SelectCommand = Cmd;

DataSet EmployeeDataSet = new DataSet();

EmployeeAdapter.Fill(EmployeeDataSet);

foreach (DataRow dr in EmployeeDataSet.Tables[0].Rows)

{

EmployeeModel tmp = new EmployeeModel();

tmp.EmployeeID = Convert.ToInt32(dr[0]);

tmp.EmployeeName = Convert.ToString(dr[1]);

tmp.EmployeeAge = Convert.ToInt32(dr[2]);

returnedValue.Add(tmp);

}

return returnedValue;

}

[WebMethod] //添加雇员信息

public void Insert(List<EmployeeModel> employee)

{

employee.ForEach( x =>

{

string CmdText = "INSERT INTO Employee(EmployeeName,EmployeeAge) VALUES('"+x.EmployeeName+"',"+x.EmployeeAge.ToString()+")";

SQLExcute(CmdText);

});

}

[WebMethod] //更新雇员信息

public void Update(List<EmployeeModel> employee)

{

employee.ForEach(x =>

{

string CmdText = "UPDATE Employee SET EmployeeName='"+x.EmployeeName+"',EmployeeAge="+x.EmployeeAge.ToString();

CmdText += " WHERE EmployeeID="+x.EmployeeID.ToString();

SQLExcute(CmdText);

});

}

[WebMethod] //删除雇员信息

public void Delete(List<EmployeeModel> employee)

{

employee.ForEach(x =>

{

string CmdText = "DELETE FROM Employee WHERE EmployeeID="+x.EmployeeID.ToString();

SQLExcute(CmdText);

});

}

//执行SQL命令文本，重载1

private void SQLExcute(string SQLCmd)

{

string ConnectionString = "PROVIDER=Microsoft.Jet.OLEDB.4.0;DATA SOURCE=" + Server.MapPath(@"App_Data\Employees.mdb;");

OleDbConnection Conn = new OleDbConnection(ConnectionString);

Conn.Open();

OleDbCommand Cmd = new OleDbCommand();

Cmd.Connection = Conn;

Cmd.CommandTimeout = 15;

Cmd.CommandType = CommandType.Text;

Cmd.CommandText = SQLCmd;

Cmd.ExecuteNonQuery();

Conn.Close();

}

//执行SQL命令文本，重载2

private void SQLExcute(string SQLCmd,OleDbCommand Cmd)

{

string ConnectionString = "PROVIDER=Microsoft.Jet.OLEDB.4.0;DATA SOURCE=" + Server.MapPath(@"App_Data\Employees.mdb;");

OleDbConnection Conn = new OleDbConnection(ConnectionString);

Conn.Open();

Cmd.Connection = Conn;

Cmd.CommandTimeout = 15;

Cmd.CommandType = CommandType.Text;

Cmd.CommandText = SQLCmd;

Cmd.ExecuteNonQuery();

}

}

}

之后，在Silverlight客户端应用程序文件夹下，右击References文件夹，选择菜单选项Add Service Reference...。如下图所示，引入刚才我们创建的Web Service（别忘了按Discover按钮进行查找）。



创建Silverlight客户端应用程序

MainPage.xaml文件

<UserControl

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

mc:Ignorable="d" xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data" xmlns:dataFormToolkit="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data.DataForm.Toolkit" x:Class="SilverlightClient.MainPage"

d:DesignWidth="320" d:DesignHeight="240">

<Grid x:Name="LayoutRoot" Width="320" Height="240" Background="White">

<dataFormToolkit:DataForm x:Name="dfEmployee" Margin="8,8,8,42"/>

<Button x:Name="btnGetData" Height="30" Margin="143,0,100,8" VerticalAlignment="Bottom" Content="Get Data" Width="77"/>

<Button x:Name="btnSaveAll" Height="30" Margin="0,0,8,8" VerticalAlignment="Bottom" Content="Save All" HorizontalAlignment="Right" Width="77"/>

<TextBlock x:Name="tbResult" Height="30" HorizontalAlignment="Left" Margin="8,0,0,8" VerticalAlignment="Bottom" Width="122" TextWrapping="Wrap" FontSize="16"/>

</Grid>

</UserControl>

MainPage.xaml.cs文件

using System;

using System.Collections.Generic;

using System.Collections.ObjectModel;

using System.Linq;

using System.Net;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Documents;

using System.Windows.Input;

using System.Windows.Media;

using System.Windows.Media.Animation;

using System.Windows.Shapes;

using System.Xml;

using System.Xml.Linq;

using System.Windows.Browser;

using SilverlightClient.EmployeesInfoServiceReference;

namespace SilverlightClient

{

public partial class MainPage : UserControl

{

int originalNum;//记录初始时的Employee表中的数据总数

ObservableCollection<EmployeeModel> deletedID = new ObservableCollection<EmployeeModel>();//标记被删除的对象

public MainPage()

{

InitializeComponent();

this.Loaded += new RoutedEventHandler(MainPage_Loaded);

this.btnGetData.Click += new RoutedEventHandler(btnGetData_Click);

this.btnSaveAll.Click += new RoutedEventHandler(btnSaveAll_Click);

this.dfEmployee.DeletingItem += new EventHandler<System.ComponentModel.CancelEventArgs>(dfEmployee_DeletingItem);

}

void dfEmployee_DeletingItem(object sender, System.ComponentModel.CancelEventArgs e)

{

deletedID.Add(dfEmployee.CurrentItem as EmployeeModel);//正在删除时，将被删除对象进行标记，以便传给服务端真正删除。

}

void btnSaveAll_Click(object sender, RoutedEventArgs e)

{

List<EmployeeModel> updateValues = dfEmployee.ItemsSource.Cast<EmployeeModel>().ToList();

ObservableCollection<EmployeeModel> returnValues = new ObservableCollection<EmployeeModel>();

if (updateValues.Count > originalNum)

{

//添加数据

for (int i = originalNum; i <= updateValues.Count - 1; i++)

{

returnValues.Add(updateValues.ToArray()[i]);

}

EmployeesInfoWebServiceSoapClient webClient = new EmployeesInfoWebServiceSoapClient();

webClient.InsertCompleted += new EventHandler<System.ComponentModel.AsyncCompletedEventArgs>(webClient_InsertCompleted);

webClient.InsertAsync(returnValues);

//必须考虑数据集中既有添加又有更新的情况

returnValues.Clear();

updateValues.ForEach(x => returnValues.Add(x));

webClient.UpdateCompleted += new EventHandler<System.ComponentModel.AsyncCompletedEventArgs>(webClient_UpdateCompleted);

webClient.UpdateAsync(returnValues);

}

else if (updateValues.Count < originalNum)

{

//删除数据

EmployeesInfoWebServiceSoapClient webClient = new EmployeesInfoWebServiceSoapClient();

webClient.DeleteCompleted += new EventHandler<System.ComponentModel.AsyncCompletedEventArgs>(webClient_DeleteCompleted);

webClient.DeleteAsync(deletedID);

}

else

{

//更新数据

updateValues.ForEach(x => returnValues.Add(x));

EmployeesInfoWebServiceSoapClient webClient = new EmployeesInfoWebServiceSoapClient();

webClient.UpdateCompleted += new EventHandler<System.ComponentModel.AsyncCompletedEventArgs>(webClient_UpdateCompleted);

webClient.UpdateAsync(returnValues);

}

}

void webClient_UpdateCompleted(object sender, System.ComponentModel.AsyncCompletedEventArgs e)

{

tbResult.Text = "更新成功！";
GetEmployees();//更新originalNum防止数据的重复插入，感谢园友紫色永恒的及时指出！

}

void webClient_DeleteCompleted(object sender, System.ComponentModel.AsyncCompletedEventArgs e)

{

tbResult.Text = "删除成功！";

}

void webClient_InsertCompleted(object sender, System.ComponentModel.AsyncCompletedEventArgs e)

{

tbResult.Text = "添加成功！";

}

void btnGetData_Click(object sender, RoutedEventArgs e)

{

GetEmployees();

}

void MainPage_Loaded(object sender, RoutedEventArgs e)

{

GetEmployees();

}

void GetEmployees()

{

EmployeesInfoWebServiceSoapClient webClient = new EmployeesInfoWebServiceSoapClient();

webClient.GetEmployeesInfoCompleted +=

new EventHandler<GetEmployeesInfoCompletedEventArgs>(webClient_GetEmployeesInfoCompleted);

webClient.GetEmployeesInfoAsync();

}

void webClient_GetEmployeesInfoCompleted(object sender, GetEmployeesInfoCompletedEventArgs e)

{

originalNum = e.Result.Count;//记录原始数据个数

dfEmployee.ItemsSource = e.Result;

}

}

}

最终效果图



作者：Kinglee
文章出处：Kinglee’s Blog (http://www.cnblogs.com/Kinglee/)
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