c# - The context cannot be used while the model is being created

Question

In my application I receive the following error:

The context cannot be used while the model is being created.

I'm not sure what this means. I have done everything as normal and usually it works but for this one it isnt. Below is my code:

App.config:

 <connectionStrings>
    <add name="DatabaseContext" connectionString="Data Source=./SQLEXPRESS;Initial Catalog=ProjectCode;Integrated Security=SSPI;" providerName="System.Data.SqlClient" />
 </connectionStrings>

Products.cs:

class Products
{
    public int ProductID { get; set; }
    public string ProductName { get; set; }
}

DatabaseContext.cs:

class DatabaseContext : DbContext
{
    public DbSet<Products> Products { get; set; }
}

Program.cs:

DatabaseContext context = new DatabaseContext();

try
{
   var products = context.Products.ToList();

   foreach (var item in products)
   {
      Console.WriteLine(item.ProductID + " : " + item.ProductName);
   }
      Console.ReadLine();
}

The line is fails on is var products = context.Products.ToList();

Any ideas what could be causing this? I have set up 2 products in my database so it should be outputting them.

EDIT

Here is my whole App.config file:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=4.3.1.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
  </configSections>
  <connectionStrings>
    <add name="DatabaseContext" connectionString="Data Source=./SQLEXPRESS;Initial Catalog=ProjectCode;Integrated Security=SSPI;MultipleActiveResultSets=true" providerName="System.Data.SqlClient" />
  </connectionStrings>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="Data Source=.SQLEXPRESS; Integrated Security=True; MultipleActiveResultSets=True" />
      </parameters>
    </defaultConnectionFactory>
  </entityFramework>
</configuration>

Answer 1

In your App.Config file under connectionstrings you had a forward slash (./SQLEXPRESS). Change this to a backslash .SQLEXPRESS like so:

<add name="DatabaseContext" connectionString="Data Source=.SQLEXPRESS;Initial Catalog=ProjectCode;Integrated Security=SSPI;" providerName="System.Data.SqlClient" />