OleDbConnection - ExecuteNonQuery需要一个开放且可用的Connection。连接的当前状态已关闭

Question

我在这里做错了什么？

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(); 
     } 
    } 
} 

。

我得到这个错误：

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线程，但没有帮助：

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

后

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

你似乎忘记打开您的连接（并分配错误连接到命令）。试试：

 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。我也推荐使用using语句。它会管理你的connection.close给你。