In this article I will explain with an example, how to use Connection String from Web.Config file in ASP.Net WCF Service using C# and VB.Net by reading the value of the Connection String from the ConnectionStrings section of the Web.Config.
In ASP.Net WCF Service project, one has to reference the System.Configuration Assembly in order to read Connection String value from the Web.Config file.
Adding ConnectionString to the Web.Config file
You need to add the Connection String in the ConnectionStrings section of the Web.Config file in the following way.
<configuration>
<connectionStrings>
<add name="ConString" connectionString="Data Source=Mudassar-PC\SQL2005;Initial Catalog=Northwind;Integrated Security=true" />
</connectionStrings>
</configuration>
Adding System.Configuration reference
The very first thing you need to do is to add reference of the System.Configuration Assembly to the project in the following way.
1. Right click on the project and click Add Reference option from the Context Menu.
![ASP.Net WCF Service: Read (Get) Connection String from Web.Config file using C# and VB.Net]()
2. From the Add Reference dialog box, click on .Net Tab and look for System.Configuration assembly. Once you find it simply select and click OK.
![ASP.Net WCF Service: Read (Get) Connection String from Web.Config file using C# and VB.Net]()
3. Once the reference is added, it will be shown in the References folder of the Solution Explorer.
![ASP.Net WCF Service: Read (Get) Connection String from Web.Config file using C# and VB.Net]()
Namespaces
You will need to import the following namespace.
C#
using System.Configuration;
VB.Net
Imports System.Configuration
Reading ConnectionString from Web.Config file in ASP.Net using C# and VB.Net
Once the reference is added, you can read the Connection String value from the Web.Config file in the following way.
C#
string connectionString = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;
VB.Net
Dim connectionString As String = ConfigurationManager.ConnectionStrings("ConString").ConnectionString
