未处理System.ArgumentException

当我在VS2005中已有项目中再新添加Windows控件库后，删去其中的UserControl1.cs文件，再对其使用调试->启动新实例，则会产生这样的一个异常！

未处理 System.ArgumentException
  Message="程序集“X:\\\\\\\\Visual Studio 2005\\Projects\\...\\WindowsControlLibrary1\\obj\\Debug\\WindowsControlLibrary1.dll”不包含任何 UserControl 类型。"
  Source="UserControlTestContainer"
  StackTrace:
       在 Microsoft.VisualStudio.Tools.UserControlTestContainer.UserControlTestContainer_Load(Object sender, EventArgs e)
       在 System.Windows.Forms.Form.OnLoad(EventArgs e)
       在 System.Windows.Forms.Form.OnCreateControl()
       在 System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
       在 System.Windows.Forms.Control.CreateControl()
       在 System.Windows.Forms.Control.WmShowWindow(Message& m)
       在 System.Windows.Forms.Control.WndProc(Message& m)
       在 System.Windows.Forms.ScrollableControl.WndProc(Message& m)
       在 System.Windows.Forms.ContainerControl.WndProc(Message& m)
       在 System.Windows.Forms.Form.WmShowWindow(Message& m)
       在 System.Windows.Forms.Form.WndProc(Message& m)
       在 System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       在 System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       在 System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       在 System.Windows.Forms.SafeNativeMethods.ShowWindow(HandleRef hWnd, Int32 nCmdShow)
       在 System.Windows.Forms.Control.SetVisibleCore(Boolean value)
       在 System.Windows.Forms.Form.SetVisibleCore(Boolean value)
       在 System.Windows.Forms.Control.set_Visible(Boolean value)
       在 System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       在 System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       在 System.Windows.Forms.Application.Run(Form mainForm)
       在 Microsoft.VisualStudio.Tools.UserControlTestContainer.Main(String[] args)