如何从 App.config 中检索连接字符串 [重复]

Question

我在 Windows 窗体应用程序中有以下配置：

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <configSections>
    </configSections>
    <connectionStrings>
        <add name="ConsoleApp1.Properties.Settings.abcdConnectionString"
            connectionString="Data Source=xxx.yyy.org;Initial Catalog=MyCatalog;"
            providerName="System.Data.SqlClient" />
    </connectionStrings>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1" />
    </startup>
</configuration>

以下代码多次尝试检索连接字符串。 没有任何效果。

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;
using System.Collections;
using System.Configuration;
using System.Collections.Specialized;


namespace ConsoleApp1  
{  
class Program  
{  
static void Main(string[] args)  
        {  
            NameValueCollection sAll;  
            sAll = ConfigurationManager.AppSettings;  
            Console.Write("[");  
            foreach (string s in sAll.AllKeys)  
            {  
                Console.Write(">>");  
                Console.WriteLine("Key: " + s + "Value: " + sAll.Get(s));  
            }  
            Console.Write("]");  
            Console.ReadLine();  
            Console.Write("sAll = (");  
            Console.Write(sAll);  
            Console.WriteLine(") end of sALL");  
            Console.ReadLine();  
            string keyvalue =  
 System.Configuration.ConfigurationManager.AppSettings["ConsoleApp1.Properties.Settings.abcdtest19ConnectionString"];  
            Console.WriteLine("keyvalue = (" + keyvalue + ")");  
            Console.ReadLine();  
            keyvalue =   ConfigurationManager.AppSettings["ConsoleApp1.Properties.Settings.abcdConnectionString"];  
            Console.WriteLine("keyvalue = (" + keyvalue + ")");  
            Console.ReadLine();  
            keyvalue =   ConfigurationManager.AppSettings["abcdConnectionString"];  
Console.WriteLine("keyvalue = (" + keyvalue + ")");  
Console.ReadLine();  
        }  
    }  
}  

这些尝试都不会产生连接字符串。 此注释是为了满足 Stackoverflow 的格式要求。

Answer 1

string constr = System.Configuration.ConfigurationManager.
   ConnectionStrings["ConsoleApp1.Properties.Settings.abcdConnectionString"].ConnectionString;

如果您像这样更改您的 app.config：

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <configSections>
    </configSections>
    <connectionStrings>
        <add name="abcdConnectionString"
            connectionString="Data Source=xxx.yyy.org;Initial Catalog=MyCatalog;"
            providerName="System.Data.SqlClient" />
    </connectionStrings>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1" />
    </startup>
</configuration>

然后

string constr = System.Configuration.ConfigurationManager.
   ConnectionStrings["abcdConnectionString"].ConnectionString;