OleDbConnection - ExecuteNonQuery需要一個開放且可用的Connection。連接的當前狀態已關閉

Question

我在這裏做錯了什麼？

using System.Data; 
using System.Data.OleDb; 

namespace myProject.Account 
{ 
    public class DbManager 
    { 

     private OleDbConnection OpenDbConnection() 
     { 
      string connectionString = GetConnectionString(); 
      return new OleDbConnection {ConnectionString = connectionString}; 
     } 

     private string GetConnectionString() 
     { 
      return "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\myDataBase.accdb"; 
     } 

     public void InsertUser(string name, string loginName, string password) 
     { 
      OleDbConnection conn = OpenDbConnection(); 

      OleDbCommand command = new OleDbCommand(
       "INSERT INTO tblUser (UserName, LoginName, Password) VALUES (@name,@login,@pwd)", 
       Conn); 

      command.Parameters.Add("@name", OleDbType.VarChar).Value = name; 
      command.Parameters.Add("@login", OleDbType.VarChar).Value = loginName; 
      command.Parameters.Add("@pwd", OleDbType.VarChar).Value = password; 
      command.ExecuteNonQuery(); 
     } 
    } 
} 

。

我得到這個錯誤：

ExecuteNonQuery requires an open and available Connection. The connection's current state is closed.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: ExecuteNonQuery requires an open and available Connection. The connection's current state is closed.

Source Error:

Line 31: command.ExecuteNonQuery();

我也想看看一些其他的線程，但沒有幫助：

ExecuteNonQuery requires an open and available Connection. The connection's current state is closed

MS Access DB doesnt save changes after execution (C#)

Answer 1

後

OleDbConnection conn = OpenDbConnection(); 

添加

conn.Open(); 

另外，修改OpenDbConnection如下：

private OleDbConnection OpenDbConnection() 
    { 
     string connectionString = GetConnectionString(); 

     OleDbConnection conn = new OleDbConnection {ConnectionString = connectionString}; 

     conn.Open(); 

     return conn; 
    } 

Answer 2

你似乎忘記打開您的連接（並分配錯誤連接到命令）。試試：

 using(OleDbConnection conn = OpenDbConnection()) 
     { 
      using(OleDbCommand command = new OleDbCommand( 
       "INSERT INTO tblUser (UserName, LoginName, Password) VALUES (@name,@login,@pwd)")) 
      { 
      command.CommandType = CommandType.Text; 
      command.Parameters.Add("@name", OleDbType.VarChar).Value = name; 
      command.Parameters.Add("@login", OleDbType.VarChar).Value = loginName; 
      command.Parameters.Add("@pwd", OleDbType.VarChar).Value = password; 
      command.Connection = conn; 

      conn.Open(); 

      command.ExecuteNonQuery(); 
      } 
     } 

取而代之。我也推薦使用using語句。它會管理你的connection.close給你。