這個類定義有什麼問題？

Question

我有這樣一個類：

class connect:IDisposable 
{ 
    public void OpenChannel(SqlConnection ch) 
    { 
    ch.ConnectionString="....."; 
    ch.Open(); 
    } 
    public void Dispose() 
    { 
    } 
} 

而另一類是這樣的：

public Cust 
{ 
    SqlConnection channel=new SqlConnection(); 
    SqlCommand command=new SqlCommand(); 

    public void Method() 
    { 
     using(connect con=new connect()) 
     { 
     con.OpenChannel(channel); 
     command.connection=channel; 
     ..... 
     .... 
     .... 
     command.ExecuteNonQuery(); 
     } 
    } 

但是當我運行ExcuteNotQuery（）有一個錯誤：「沒有打開的連接」 那麼，什麼是錯誤？

Answer 1

public Cust 
{ 
    SqlConnection channel=new SqlConnection(); 
    SqlCommand command;//=new SqlCommand(); 

    public void Method() 
    { 
     using(connect con=new connect()) 
     { 
     con.OpenChannel(channel); 
     //command.connection=channel; 

     // create command from open connection 
     command = channel.CreateCommand(); 
     ..... 
     .... 
     .... 
     command.ExecuteNonQuery(); 
     } 
    }