Get ConnectionString from app.config in c# [duplicate]

问题

This question already has answers here:

Get connection string from App.config (18 answers)

Closed 6 years ago.

I have defined my connection String in app.config file

<?xml version="1.0" encoding="utf-8" ?>
<configuration>

  <connectionStrings>

    <add name="CString" 
         connectionString="Data Source=Bilal-PC;Initial Catalog=ATMSoftware;Integrated Security=False; User Id=sa; Password=123" 
         providerName="System.Data.SqlClient"/>
  </connectionStrings>
</configuration>

Now I want to get it into my C# class and I have tried all the methods. but I am getting an error on configuration manager.

Please help me.

回答1:

Ensure that you have added a reference to System.Configuration in your project, and place a

using System.Configuration;

statement at the top of your source. The ConfigurationManager type should now be available.

string connectionString = ConfigurationManager.ConnectionStrings["CString"].ConnectionString;

回答2:

See MSDN for more information

var conString = ConfigurationManager.ConnectionStrings["LocalSqlServer"];
string strConnString = conString.ConnectionString;

来源：https://stackoverflow.com/questions/8693492/get-connectionstring-from-app-config-in-c-sharp