title: Using a VB class from the same ASP.NET web site project in a C# class
body: <p>I have an ASP.NET web site project where I am using both VB.Net and C# class files. I have included separate sub folders in the App_Code directory for classes of each language.</p>
  
  <p>However, while I can successfully make use of a C# class in a VB class, I cannot do the opposite: use a a VB class in a C# class. </p>
  
  <p>So, to illustrate, I might have two classes such as this:</p>
  
  <pre><code>Public Class VBTestClass
      Public Sub New()
      End Sub
  
      Public Function HelloWorld(ByVal Name As String) As String
          Return Name
      End Function
  End Class
  
  public class CSTestClass
  {
      public CSTestClass()
      {
      }
      public string HelloWorld(string Name)
      {
          return Name;
      }
  
  }
  </code></pre>
  
  <p>I can make use of the CS class in my VB class, with the "Imports" statement. So this works well:</p>
  
  <pre><code>Imports CSTestClass
  Public Class VBTestClass
      Public Sub New()
      End Sub
  
      Public Function HelloWorld(ByVal Name As String) As String
          Return Name
      End Function
  
    Private Sub test()
        Dim CS As New CSTestClass
        CS.HelloWorld("MyName")
     End Sub
  End Class
  </code></pre>
  
  <p>But making use of the VB class in my C#, with the "using" statement, does not work:</p>
  
  <pre><code>using VBTestClass;
  public class CSTestClass
  {
        public CSTestClass()
        {
    }
  
       public string HelloWorld(string Name)
      {
          return Name;
      }
  }
  </code></pre>
  
  <p>I get an error that "the type or namespace "VBTestClass" could not be found". What am I missing here? </p>