ExecuteNonQuery:尚未初始化Connection属性.

Question

下午,所以我已经在这个问题上待了几个小时,并且无法真正超越这个最后的驼峰.以下是我写的这个程序的代码:

using System;  
using System.Collections.Generic;  
using System.Linq;  
using System.Text;  
using System.Diagnostics;  
using System.Data;  
using System.Data.SqlClient;  
using System.Configuration;  

namespace Test  
{  
  class Program  
  {  
    static void Main()  
    {  
      EventLog alog = new EventLog();  
      alog.Log = "Application";  
      alog.MachineName = ".";  
      foreach (EventLogEntry entry in alog.Entries)  
      {  
       SqlConnection connection1 = new SqlConnection(@"Data Source=.\sqlexpress;Initial Catalog=syslog2;Integrated Security=True");  
       SqlDataAdapter cmd = new SqlDataAdapter();  
       cmd.InsertCommand = new SqlCommand("INSERT INTO Application VALUES (@EventLog, @TimeGenerated, @EventType, @SourceName, @ComputerName, @InstanceId, @Message) ");  
       cmd.InsertCommand.Parameters.Add("@EventLog",SqlDbType.VarChar).Value = alog.Log;  
       cmd.InsertCommand.Parameters.Add("@TimeGenerated", SqlDbType.DateTime).Value = entry.TimeGenerated;  
       cmd.InsertCommand.Parameters.Add("@EventType", SqlDbType.VarChar).Value = entry.EntryType;  
       cmd.InsertCommand.Parameters.Add("@SourceName", SqlDbType.VarChar).Value = entry.Source;  
       cmd.InsertCommand.Parameters.Add("@ComputerName", SqlDbType.VarChar).Value = entry.MachineName;  
       cmd.InsertCommand.Parameters.Add("@InstanceId", SqlDbType.VarChar).Value = entry.InstanceId;  
       cmd.InsertCommand.Parameters.Add("@Message", SqlDbType.VarChar).Value = entry.Message;  
       connection1.Open();  
       cmd.InsertCommand.ExecuteNonQuery();  
       connection1.Close();  
      }   
    }  
  }  
} 

代码编译正常,没有错误或警告,但当我去运行它,一旦它到达cmd.InsertCommand.ExecuteNonQuery(); 我收到以下错误:

ExecuteNonQuery:尚未初始化Connection属性.

关于我错过的任何想法？

Answer 1

您需要将连接分配给SqlCommand,您可以使用构造函数或属性:

cmd.InsertCommand = new SqlCommand("INSERT INTO Application VALUES (@EventLog, @TimeGenerated, @EventType, @SourceName, @ComputerName, @InstanceId, @Message) ");
cmd.InsertCommand.Connection = connection1;

我强烈建议使用using-statement任何类型的执行IDisposable类似SqlConnection,它也将关闭连接:

using(var connection1 = new SqlConnection(@"Data Source=.\sqlexpress;Initial Catalog=syslog2;Integrated Security=True"))
using(var cmd = new SqlDataAdapter())
using(var insertCommand = new SqlCommand("INSERT INTO Application VALUES (@EventLog, @TimeGenerated, @EventType, @SourceName, @ComputerName, @InstanceId, @Message) "))
{
    insertCommand.Connection = connection1;
    cmd.InsertCommand = insertCommand;
    //.....
    connection1.Open();
    // .... you don't need to close the connection explicitely
}

除此之外,您不需要创建新连接,并且DataAdapter对于每个条目foreach,即使创建,打开和关闭连接也不意味着ADO.NET将创建,打开和关闭物理连接,但只是查看连接池用于可用连接.然而,这是一个不必要的开销.

Answer 2

你没有初始化连接.这就是为什么会发生这种错误的原因.

你的代码:

cmd.InsertCommand = new SqlCommand("INSERT INTO Application VALUES (@EventLog, @TimeGenerated, @EventType, @SourceName, @ComputerName, @InstanceId, @Message) ");

更正代码:

cmd.InsertCommand = new SqlCommand("INSERT INTO Application VALUES (@EventLog, @TimeGenerated, @EventType, @SourceName, @ComputerName, @InstanceId, @Message) ",connection1);