微软Visual c++曾经这样做，但Visual Studio不AFAIK..：(

关于Visual Studio 2015:

根据Marc Gravell目前公认的答案:

此功能已添加到Visual Studio 2013。你可以看到回报 值在自动窗口或使用$ReturnValue在手表/立即 窗口

该回答还指出，该功能在Visual Studio 2015中无法工作。这并不(完全)正确。在检查方法调用的返回值时，有以下注意事项:

必须打开遗留表达式求值器才能识别$ReturnValue(工具/选项/调试/使用遗留c#和VB表达式求值器)。否则，您可以使用$ReturnValue1。

我在Visual Studio 2015 Enterprise中进行了测试:

关闭遗留表达式求值器:只有$ReturnValue1有效 打开遗留表达式求值器:$ReturnValue和$ReturnValue1都可以工作

我知道的唯一方法是在返回行上放置一个断点，然后调用Quick Watch窗口并输入返回的表达式:

someTableAdapter.getSomeData();

但这只有在调用不改变任何对象的状态时才有效(因为当您恢复执行时，将会对同一方法进行第二次调用)。

在VS2019中，只需打开调试->Windows->汽车窗口。在那里，你看到concat返回值如下所示:

根据微软的说法，没有办法用托管代码可靠地实现这一点。这是他们意识到并正在努力解决的问题:

For those out there who have experience debugging native C++ or VB6 code, you may have used a feature where function return values are provided for you in the Autos window. Unfortunately, this functionality does not exist for managed code. While you can work around this issue by assigning the return values to a local variable, this is not as convenient because it requires modifying your code. In managed code, it’s a lot trickier to determine what the return value of a function you’ve stepped over. We realized that we couldn’t do the right thing consistently here and so we removed the feature rather than give you incorrect results in the debugger. However, we want to bring this back for you and our CLR and Debugger teams are looking at a number potential solutions to this problem. Unfortunately this is will not be part of Visual Studio 11.

https://connect.microsoft.com/VisualStudio/feedback/details/597933/add-a-return-pseudo-variable-to-the-visual-studio-debugger-for-net-code

接受的答案在Visual Studio 2015中不能正常工作，但是通过在方法的最后一行上放置断点并按F10，它将把返回值的所有表达式放入locals窗口。