How to compile CS/VB file and place new DLL in bin subdirectory

You can build a dll using the following command line .
Assuming your command window has the appropriate path set to use the following exes:

VB.NET compiler vbc.exe

vbc.exe /out:SyncVB.dll /target:library SyncVB.vb

C# compiler csc.exe

csc.exe /out:SyncCS.dll /target:library SyncCS.cs 

To reference it within the .aspx page use the Import directive:

<%@ Import Namespace=’SyncVB’ %>

or

<%@ Import Namespace=’SyncCS’ %>