更新“我如何称呼另一个班级的班级” [英] Update "How I Call A Class In Another Class"

问题描述

我有一个连接字符串类，我需要在另一个类中调用这个类，用于sql命令，用于将值插入带有存储过程的表中。



连接字符串的第一类代码：

I have a class for connection string and i need to call this class in another class for a sql command for insert a value into a table with a stored procedure.

Code for the first class for connection string:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data;
using System.Data.Sql;
using System.Data.SqlClient;

namespace GestiuneP
{
    class Conectare
    {
        public static SqlConnection con = null;

        public static void Conexiune()
        {
            con = new SqlConnection(@"Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Users\Vali&Aurelian\Documents\GestiuneP.mdf;Integrated Security=True;Connect Timeout=30");
            con.Open();
        }
    }
}

和第二堂课用于sql命令，用于将值插入带有存储过程的表中

and the second class for a sql command for insert a value into a table with a stored procedure

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data;
using System.Data.Sql;
using System.Data.SqlClient;
 
namespace GestiuneP
{
    
    class Adauga_Angajat
    {
        Conectare NewConnection = new Conectare();
        NewConnection.Conexiune();// here is the error: "GestiuneP.Adauga_Angajat.NewConnection is a field but is used like a type"
        SqlCommand myCommand = new SqlCommand("dbo.[sp_adauga_client]", con);
        myCommand.CommandType = CommandType.StoredProcedure;


    }
}

推荐答案

正如我之前解释的那样你调用的方法是静态定义，但您将其用作实例方法。所以要么使它成为实例方法，要么在调用中使用类名。



所以要么

As I explained earlier the method you call is defined static but you use it as an instance method. So either make it an instance method or use the class name in the call.

So either

class Conectare
{
    public static SqlConnection con = null;

    public void Conexiune() // static is removed
    {
        con = new SqlConnection(@"Data Source=(LocalDB)\v11.0;AttachDbFilename=C:\Users\Vali&Aurelian\Documents\GestiuneP.mdf;Integrated Security=True;Connect Timeout=30");
        con.Open();
    }
}

或

or

//Conectare NewConnection = new Conectare();
Conectare.Conexiune();// Class name used

我个人更喜欢第二个这种情况。



作为旁注，您似乎将SqlConnection存储了一段时间，这是单个操作所需的。如果是这种情况，我建议不要这样做。相反，当您需要连接时，创建并打开它，执行SQL命令，最后正确关闭连接。

Personally I would prefer the second one in this situation.

As a side note, you seem to store the SqlConnection for a longer period of time that is needed for a single operation. If that is the case, I would suggest not doing so. Instead, when you need the connection, create and open it, execute the SQL commands and at the end close the connection properly.

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