SqlTransaction 数据库编程事务使用示例

在提交或回滚 SqlTransaction 时，应始终使用 Try/Catch 进行异常处理。如果连接终止或事务已在服务器上回滚，则 Commit 和 Rollback 都会生成 InvalidOperationException。
 
下面的示例创建一个 SqlConnection 和一个 SqlTransaction。此示例还演示如何使用 BeginTransaction、Commit 和 Rollback 等方法。出现任何错误时事务都会回滚。Try/Catch 错误处理用于处理尝试提交或回滚事务时的所有错误。

using System;
using System.Configuration;
using System.Data.SqlClient;
using System.Transactions;



protected void Page_Load(object sender, EventArgs e)
        {
            
            using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnStr"].ToString()))
            {
                conn.Open();
                SqlTransaction _transaction = conn.BeginTransaction();                  
                try
                {
                    SqlCommand _cmd = new SqlCommand("Insert Into T_Test(F_Name) values(@Name)",conn);
                    _cmd.Parameters.Add(new SqlParameter("@Name", "Test1"));
                    _cmd.Transaction = _transaction;
                    _cmd.ExecuteNonQuery();

                    _cmd.Parameters.Clear();
                    _cmd.Parameters.Add(new SqlParameter("@Name", "Test2" + new String('2', 100)));
                    _cmd.ExecuteNonQuery();//F_Name为Nvarchar(50)，这里会报错

                    _transaction.Commit();

                    Response.Write("二条记录已经成功入库!");
                }
                catch (Exception ex)
                {
                    Response.Write("发生错误：" + ex.Message.ToString());
                    try
                    {
                        _transaction.Rollback();
                        Response.Write("<br/>事务已成功回滚!");
                    }
                    catch (Exception ex2)
                    {
                        Response.Write("<br/>回滚失败：" + ex2.Message.ToString());
                    }
                }
                _transaction.Dispose();
            }
        }  

如果换成时下流行的Linq To Sql写法，大致如下：

using (DataContext context = new DataContext(connStr))
            {

                SqlConnection conn = new SqlConnection();                   
                if (context.Connection != null && context.Connection.State!=ConnectionState.Open) context.Connection.Open();

                context.Transaction = context.Connection.BeginTransaction();
                try
                {
                    User user = new User();
                    user.Name = "aaaa";
                    users.Add(user);
                    context.SubmitChanges();

                    users.Remove(users.Single(u => u.Name == "aaaa"));
                    context.SubmitChanges();

                    context.Transaction.Commit();
                }
                catch
                {
                    try
                    {
                        context.Transaction.Rollback();
                    }
                    catch 
                    {
                        //
                    }
                }
            }