C# winform程序 事务处理解决办法

C# winform程序 事务处理
各位大侠给看下，下面的代码有什么问题，现在现象是我去掉 
SqlTransaction sqltran = conn.BeginTransaction(); sqltran.Commit(); sqltran.Rollback();这三句后程序可以正常，但是加上这三句后就不行了，事务处理要怎么来写请各位指教！！！
 

C# code

 SqlConnection conn = new SqlConnection("server= .\\SQLEXPRESS;uid=testuser1;pwd=test123;database=manage");            conn.Open();           SqlTransaction sqltran = conn.BeginTransaction();            try            {                for (int i = 0; i < 1000; i++)                {                    SqlCommand sql = new SqlCommand("UPDATE [newplan] SET [dept] = '" + i + "' WHERE [number]='11'", conn);                    sql.ExecuteNonQuery();                    txt_number.Text = i.ToString();                }                 sqltran.Commit();            }            catch            {               sqltran.Rollback();            }            finally            {                conn.Close();            }

C# code

SqlConnection conn = new SqlConnection("server= .\\SQLEXPRESS;uid=testuser1;pwd=test123;database=manage");SqlCommand cmd = new SqlCommand();            conn.Open();           SqlTransaction sqltran = conn.BeginTransaction();cmd.Connection=conn;cmd.Transaction = sqltran;            try            {                for (int i = 0; i < 1000; i++)                {                    cmd.CommandText = "UPDATE [newplan] SET [dept] = '" + i + "' WHERE [number]='11'");                    cmd.ExecuteNonQuery();                    txt_number.Text = i.ToString();                }                 sqltran.Commit();            }            catch            {               sqltran.Rollback();            }            finally            {                conn.Close();            }
[解决办法]
cmd.Transaction = sqltran;

这是关键。
[解决办法]
是的，要把事务赋予Command.