C# constructor "Object reference not set to an instance of an object."
In a C# 2008 application I am getting the error message "Object reference not set to an instance of an object."
The line of code that is causing this to occur is the following:
public eDataContext() :
base(ConfigurationManager.ConnectionStrings["DEVConnectionString"].ConnectionString, mappingSource).
I have a reference set to system.configuration and I have a using System.Configuration.
Below you will find my app.config file and code that I am referring to:
app.config file code:
<connectionStrings>
<add name="esample.Properties.Settings.RPCSS_DEVConnectionString"
connectionString="Data Source=DEV2;Initial Catalog=DEV;Integrated Security=True"
providerName="System.Data.SqlClient" />
</connectionStrings>
The actual code:
namespace eclient
{
using System.Data.Linq;
using System.Data.Linq.Mapping;
using System.Data;
using System.Collections.Generic;
using System.Reflection;
using System.Linq;
using System.Linq.Expressions;
using System.ComponentModel;
using System;
using System.Configuration;
public partial class eDataContext : System.Data.Linq.DataContext
{
[System.Data.Linq.Mapping.DatabaseAttribute(Name = "DEV")]
private static System.Data.Linq.Mapping.MappingSource mappingSource = new AttributeMappingSource();
public eDataContext() :
base(ConfigurationManager.ConnectionStrings["DEVConnectionString"].ConnectionString, mappingSource)
{
OnCreated();
}
public eDataContext(string connection) :
base(connection, mappingSource)
{
OnCreated();
}
public eDataContext(System.Data.IDbConnection connection) :
base(connection, mappingSource)
{
OnCreated();
}
public eDataContext(string connection, System.Data.Linq.Mapping.MappingSource mappingSource) :
base(connection, mappingSource)
{
OnCreated();
}
public eDataContext(System.Data.IDbConnection connection, System.Data.Linq.Mapping.MappingSource mappingSource) :
base(connection, mappingSource)
{
OnCreated();
}
Thus can you tell me how to fix this code?