System.Transactions 命名空间中除了上一节中提到的基于 Transaction 类的显式编程模型，还提供使用 TransactionScope 类的隐式编程模型，它与显示编程模型相比，更加方便简单，它也是MSDN中建议使用的编程模型。
下面，我们基于TransactionScope类实现上一节银行转帐的例程。
示例代码：
（1）SqlHelper.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Configuration;
using MySql.Data.MySqlClient;
using System.Transactions;
using System.Data;
namespace 事务处理
{
public class SqlHelper
{
public static string GetConnection()
{
string connStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
return connStr;
}
public static int ExecuteNonQuery(string sql, params MySqlParameter[] parameters)
{
int result = -1;
using (MySqlConnection conn = new MySqlConnection(GetConnection()))
{
conn.Open();
using (MySqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = sql;
cmd.Parameters.AddRange(parameters);
result = cmd.ExecuteNonQuery();
}
}
return result;
}
public static DataTable ExecuteDataTable(string sql, params MySqlParameter[] parameters)
{
using (MySqlConnection conn = new MySqlConnection(GetConnection()))
{
using (MySqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = sql;
cmd.Parameters.AddRange(parameters);
using (MySqlDataAdapter da = new MySqlDataAdapter(cmd))
{
using (DataSet ds = new DataSet())
{
da.Fill(ds);
return ds.Tables[0];
}
}
}
}
}
}
}
（2）Bankaccountn.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using MySql.Data.MySqlClient;
using System.Data;
using System.Transactions;
namespace 事务处理
{
public class Bankaccountn
{
public Bankaccountn(string bankaccountnId)
{
string sql = @"SELECT * FROM Bankaccountn WHERE BankaccountnId=@BankaccountnId;";
DataTable dt = SqlHelper.ExecuteDataTable(sql, new MySqlParameter("@BankaccountnId", bankaccountnId));
if (dt.Rows.Count <= 0)
{
throw new Exception("账户不存在！");
}
else if (dt.Rows.Count > 1)
{
throw new Exception("异常信息：有重名的账户存在！");
}
else
{
this.bankaccountnId = dt.Rows[0]["BankaccountnId"] as string;
this.UserName = dt.Rows[0]["UserName"] as string;
this.Balance = Convert.ToDecimal(dt.Rows[0]["Balance"]);
}
}
private string bankaccountnId;
public string UserName
{
get;
private set;
}
public decimal Balance
{
get;
private set;
}
protected int Update()
{
string sql = @"UPDATE bankaccountn SET UserName = @UserName,Balance = @Balance
WHERE BankaccountnId= @BankaccountnId;";
return SqlHelper.ExecuteNonQuery(sql, new MySqlParameter("@BankaccountnId", this.bankaccountnId), new MySqlParameter("@UserName", this.UserName), new MySqlParameter("@Balance", this.Balance));
}
public void Epend( decimal money)
{
this.Balance -= money;
this.Update();
}
public void Income(decimal money)
{
this.Balance += money;
this.Update();
}
public bool HiddenTransferOfAccount(string incomeBankaccountnId, decimal money)
{
bool result = true;
using (TransactionScope scope = new TransactionScope())
{
try
{
Bankaccountn incomeBankaccountn = new Bankaccountn(incomeBankaccountnId);
incomeBankaccountn.Income(money); //收款账户入账
this.Epend(money); //付款账户支出
scope.Complete();
}
catch (Exception ex)
{
//这里写做异常信息的记录的代码
result = false;
}
}
return result;
}
}
}
（3）测试代码
Bankaccountn one = new Bankaccountn("6666660123456789");
if (one.HiddenTransferOfAccount("6666669876543210", 200M))
{
Response.Write("<script>alert('转账成功')</script>");
}
else
{
Response.Write("<script>alert('转账失败')</script>");
}
代码分析：
使用TransactionScope 之后，事务管理器会 预执行代码，直至Complete()处，如果过程没有出错，这通知事务管理器去提交，如果错误就不提交，保证了整个执行过程的一致性。
但，在使用隐式编程模型时应注意以下几点：
1）要确保参与事务的资源（如连接的打开等）的全登记放在TransactionScope 实例化对象之后，调用Complete()方法之前。
2）从TransactionScope 实例化到调用Complete()方法之间的代码，不要吃掉异常。
using (TransactionScope scope = new TransactionScope())
{
try
{
//要确保参与事务的资源全部登记在这个位置（如连接的打开等）
Bankaccountn incomeBankaccountn = new Bankaccountn(incomeBankaccountnId);
incomeBankaccountn.Income(money); //收款账户入账
this.Epend(money); //付款账户支出
scope.Complete();
}
catch (Exception ex)
{
//捕获异常要在这个位置
result = false;
}
}