我正在尝试创建一个类来获取和设置sql c中的值＃ [英] I am trying to create a class to get and set values within sql c#

问题描述

大家好，



所以我试图在我的应用程序中创建一个类来启动与sql的连接，并在表中获取和设置值

 使用系统; 
 使用 System.Collections.Generic; 
 使用 System.Linq; 
 使用 System.Text; 
 使用 System.Threading.Tasks; 
 使用 System.Configuration; 
 使用 System.Data.SqlClient; 
 
 
 命名空间 ConsoleApplication1 
 {
  public   class  EQData 
 {
  public   string  x_id { get ;  set ; } 
  public   string  fullname { get ;  set ; } 
  public   string  email { get ;  set ; } 
  public  EQData（）
 {
 SQLConnect sqlcon =  new 的SQLConnect（）; 
 SqlDataReader myReader =  null ; 
 SqlCommand myCommand =  new  SqlCommand（  select x_id，fullname，email FROM cas_user_ext WHERE fullname = @fullname，
 sqlcon.Connection）; 
 myCommand.Parameters.AddWithValue（  @ fullname，  Ivan Lubbe）; 
 myReader = myCommand.ExecuteReader（）; 
  while （myReader.Read（））
 {
 x_id = myReader [   x_id]; 
 fullname = myReader [  fullname]; 
 email = myReader [  email]; 
} 
 sqlcon.Close（）; 
} 
} 
} 

这是我的代码。老实说，我有点困惑，我正在看2x教程（示例代码），他们让我困惑



http://stackoverflow.com/questions/13410210/creating-a-class-to-interact-with-a- sql-database [ ^ ]



http://msdn.microsoft.com/en-us/library/ms173109.aspx [ ^ ]



我收到错误无法隐式转换'对象'为'字符串'



我用来引用我班级的行是

  var  EQData =  new  EQData（）; 
  //   EQData.fullname = myReader [Test User];  
 Console.WriteLine（EQData.fullname）; 
  //   string name = EQData.fullname;  
 

我已经测试了几行，但我显然没有做到这一点。并且实际上没有合适的教程解释如何使用get和set来读取和写入数据到sql的类。任何参考和帮助将不胜感激。

解决方案

您的问题是这段代码：

 x_id = myReader [  x_id]; 
 fullname = myReader [  fullname]; 
 email = myReader [  email]; 

数据读取器将对象存储为对象类型，并且您尝试将它们分配给字符串。



您可以这样做：

 x_id = myReader [  。X_ID]的ToString（）; 
 fullname = myReader [  fullname]。ToString（）; 
 email = myReader [  email]。ToString（）; 

但请注意，当您处理不同类型时，您需要进行适当的转换。



如：



如果你的ID实际上是一个int而不是一个字符串

 x_id =  Int32  .Parse（myReader [  x_id]）; 

问题应该在这里：

 x_id = myReader [  x_id]; 

这部分代码将返回值作为对象。你不能设置变量哪个是字符串对象值。

解决方案：

 x_id = myReader [  x_id]。ToString（）; 
 fullname = myReader [  fullname]。ToString（）; 
 email = myReader [  email]。ToString（）; 

Hi all,

So im trying to create a class within my application that initiates a connection to sql and also gets and sets values within a table

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


namespace ConsoleApplication1
{
    public class EQData
    {
        public string x_id { get; set; }
        public string fullname { get; set; }
        public string email { get; set; }
        public EQData()
        {
            SQLConnect sqlcon = new SQLConnect();
            SqlDataReader myReader = null;
            SqlCommand myCommand = new SqlCommand("select x_id, fullname, email FROM cas_user_ext WHERE fullname = @fullname",
                                                                                    sqlcon.Connection);
            myCommand.Parameters.AddWithValue("@fullname", "Ivan Lubbe");
            myReader = myCommand.ExecuteReader();
            while (myReader.Read())
            {
                x_id = myReader["x_id"];
                fullname = myReader["fullname"];
                email = myReader["email"];
            }
            sqlcon.Close();
        }
    }
}

This is my code. Honestly i am a little confused i'm looking at 2x tutorials (sample code) and they are confusing me

http://stackoverflow.com/questions/13410210/creating-a-class-to-interact-with-a-sql-database[^]

http://msdn.microsoft.com/en-us/library/ms173109.aspx[^]

I am getting the error "Cannot implicitly convert 'object' to 'string'

The lines i'm using to reference my class is

 var EQData = new EQData();
// EQData.fullname = myReader["Test User"];
 Console.WriteLine(EQData.fullname);
 //string name = EQData.fullname;

I've commented out a few lines as i tested but i'm obviously not getting this right. And there are really no decent tutorials explaining on how to use a class with get and set to read and write data to sql. Any references and help would be greatly appreciated.

解决方案

Your issue is this section of code:

x_id = myReader["x_id"];
              fullname = myReader["fullname"];
              email = myReader["email"];

The Data reader stores the objects as "object" types and you are trying to assign them to strings.

You could do:

x_id = myReader["x_id"].ToString();
              fullname = myReader["fullname"].ToString();
              email = myReader["email"].ToString();

But be aware when you are handling different types you need to do the appropriate conversion.

Such as:

If your ID was in fact an int instead of a string

x_id = Int32.Parse(myReader["x_id"]);

Hi,
problem should be here:

x_id = myReader["x_id"];

this part of code will return value as object. You can not set variable which is string object value.
Solution:

x_id = myReader["x_id"].ToString();
fullname = myReader["fullname"].ToString();
email = myReader["email"].ToString();

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