ConfigurationManager throwing null exception when trying to read connection string in .NET 4.0

Question

I am working on .NET Framework 4.0 Class Library project along with ADO.NET. I have connectionString inside the App.config which I am trying to read using ConfigurationManager but getting null reference exception.

Error

app.config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
  </configSections>
 <connectionStrings>
    <add name ="dbConnection" connectionString="Data Source=xyz;Integrated Security=True" providerName="System.Data.SqlClient" />
</connectionStrings>
</configuration>

Reading ConnectionString

using System.Configuration;

var x22 = ConfigurationManager.ConnectionStrings["dbConnection"].ConnectionString;

Answer 1

In your solution explorer and under reference node, check if assembly System.Configuration has been added related to you needed Configuration Class and there is not any error regarding to your references.

But, your code is correct and I suggest to you try to avoid this error by checking null situation in return value of that command. Maybe config file is not exist in your default path. check config file to be exist then try to read it's data.

Answer 2

in app config

<connectionStrings>
    <add name="[name]" connectionString="[YOUR CONNECTION]" />
</connectionStrings>

call your connectionString

 ConfigurationManager.ConnectionStrings["name"].ConnectionString