在清理解决方案的基础上，您可以检查/清空 obj\debug 文件夹.我可能错了，但我认为 Visual Studio 设计器使用了其中的几个文件.

On top of cleaning the solution, you can check/empty the obj\debug folder. I might be wrong, but I think several files in there are used by the Visual Studio designer.

另外，根据this，添加;assembly= 在像这样的自定义命名空间声明的末尾可以解决问题:

Also, according to this, adding ;assembly= at the end of your custom namespace declaration like this could solve the problem:

xmlns:local="clr-namespace:Insurance_MidAm_Interface;assembly="