c# - 如何在类库的类中显示消息框？

Question

谁能告诉我如何在 C# 中的类库项目的 .cs 文件中显示警报消息？

我在类库项目中调用cs文件的方法。每当控件进入方法内的警报消息语句时，应在网页（aspx）上显示警报消息，并且不应执行警报消息语句的下一条语句。

Answer 1

小心不要在类库中放置过多的 UI 代码。听起来您的类库方法应该引发异常。然后调用代码可以捕获异常并根据需要将其显示给用户。

Answer 2

In an application made of well-defined tiers, this should never be done.

There is a lack of detail in the question as to what you're trying to accomplish by doing this, but here are a few possibilities and solutions:

• Using the alert as a substitute for debugging? Use the debugger and step through your code; inspect the variables as necessary.
• Trying to capture the message of an exception that's getting thrown? Let the exception bubble up to the UI layer where you can catch it and show the message.
• Trying to return a string from a database or from a localized lookup table? Return it as the result of a function or property, and show the value from the UI layer.

Answer 3

您的类库方法应该将错误返回给调用者，是否显示错误取决于调用者。