This exception indicates that the file specified in a DLL import could not be found (see System.Runtime.InteropServices.DllImportAttribute). This exception is thrown only when you attempt to link against a method declared using the P/Invoke features of .NET. Any managed DLL (such as those produced by C# or Visual Basic .NET) that cannot be found instead generates TypeLoadExceptions when you attempt to resolve types out of an assembly that cannot be found.

public class DllNotFoundException : TypeLoadException {
// Public Constructors
   public DllNotFoundException( );
   public DllNotFoundException(string message);
   public DllNotFoundException(string message,  Exception inner);
// Protected Constructors
   protected DllNotFoundException(System.Runtime.Serialization.SerializationInfo info,
        System.Runtime.Serialization.StreamingContext context);
}

Hierarchy

Object Exception(System.Runtime.Serialization.ISerializable) SystemException TypeLoadException DllNotFoundException