请教一段ADO.NET的代码

Question

代码出错！请问如何改正
SqlConnection conn = new SqlConnection(@"Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=AdventureWorks;Data Source=.");
            conn.Open();
            Console.WriteLine("1");
            SqlDataAdapter da = new SqlDataAdapter("select AddressId,City from Person.Address", conn);
            DataSet ds = new DataSet();            
             da.UpdateCommand= new SqlCommand();
             da.UpdateCommand.CommandText = "Update CustomerInfo set City=@City where (AddressId=@AddressId)";
             SqlParameter AddressId = new SqlParameter("@AddressId", SqlDbType.Int);
             SqlParameter City = new SqlParameter("@City", SqlDbType.NVarChar);
            AddressId.Value = 4;
            City.Value = "234";
            da.UpdateCommand.Parameters.Add(AddressId);
            da.UpdateCommand.Parameters.Add(City);
            da.Fill(ds, "Address");
            da.UpdateCommand.ExecuteNonQuery();            
            da.Update(ds);错误：
未处理 System.InvalidOperationException
  Message="ExecuteNonQuery: Connection 属性尚未初始化。"
  Source="System.Data"
  StackTrace:
       在 System.Data.SqlClient.SqlCommand.ValidateCommand(String method, Boolean async)
       在 System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)
       在 System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
       在 ConsoleApplication1.Program.Main(String[] args) 位置 D:\Test\ConsoleApplication1\ConsoleApplication1\Program.cs:行号 27
       在 System.AppDomain.nExecuteAssembly(Assembly assembly, String[] args)
       在 System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       在 Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       在 System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       在 System.Threading.ThreadHelper.ThreadStart()

Answer 1

SqlDataAdapter da = new SqlDataAdapter("select AddressId,City from Person.Address", conn);
 da.UpdateCommand.CommandText = "Update CustomerInfo set City=@City where (AddressId=@AddressId)";
上面的语句不成立.
幫頂!

Answer 2

da.UpdateCommand.ExecuteNonQuery();            
da.Update(ds);1.UpdateCommand没有指定Connection属性
2.执行da.Update就不需要执行da.UpdateCommand.ExecuteNonQuery()，重新理解一下Adapter的意义。

Answer 3

da.UpdateCommand= new SqlCommand();
=〉
da.UpdateCommand= new SqlCommand(@"Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=AdventureWorks;Data Source=.");

Answer 4

想问一下
SqlConnection conn = new SqlConnection(@"Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=AdventureWorks;Data Source=.");干嘛要多出个@
 new SqlConnection(@"Integrated Security=SSPI;Persist