虽然有几个很好的答案，从通常的怀疑到更新的解决方案，但我想再提供一个解决方案，以解决当您在多个项目中处理一个解决方案时应该做的事情。

在得到这个解决方案之前，我一直在应用程序主机中查看bindingInformation。配置解决方案，不知疲倦地寻找为什么事情不工作的任何线索。

事实证明，我忽略了一个简单的事情，那就是不同的项目也有各自的设置。 因此，除了Project > {Project- name}属性…> Web >开始行动在我的后端项目，我还必须去网站>开始选项…开始行动在我的Frontend项目。在那里，我选择了不要打开页面。等待来自外部应用程序的请求，从那时起就一直很快乐!

.NET核心Web Api项目的更新答案…

右键单击项目，选择“属性”，转到“调试”，取消“启动浏览器”复选框(默认启用)。

您现在还可以通过单击Run按钮旁边的下拉箭头来访问Web属性!

点击“运行”旁边的下拉按钮 {项目名称}属性 点击左侧列表中的“Web” 在“开始操作”段下，单击“不打开页面”。

你都准备好了!

PS:这对我来说是有效的，我使用的是VS Professional 2019的16.5.5版本:)

当你第一次打开一个web/应用程序项目时，按Ctrl-F5，这是启动应用程序而不调试的快捷方式。然后，当您随后按下F5并启动调试器时，它将使用该IE实例。然后在Visual Studio中停止并启动调试，而不是关闭IE。

它在我的机器上工作。我正在使用内置的开发web服务器。不知道这有什么区别。

Firefox也将保持打开状态，因此您可以同时在其中一个或两个中进行调试。

I looked over the answers and didn't see the solution I found mentioned. If it was, my apologies. In my case, currently using Visual Studio 2015. In the solution explorer, right click on the Project file and click properties. Go to the Debug tab and this should have info for how you're launching "IIS Express or Web(DNX)" for the first two drop downs, and then there should be a checkmark box for "Launch URL:". Uncheck this option and your browser won't be automatically launched everytime you go to debug your application. Hope this helps someone out.

There seems to be one case in which none of the above but the following helps. I'm developing a project for Windows Azure cloud platform and I have a web role. There is indeed a radio button Don't open page in Project -> {Project name} properties... as was pointed out by Pawel Krakowiak, but it has no effect in my case whatsoever. However, there is the main cloud project in solution explorer and there is the Roles folder under it. If I right click my web role in this folder and choose Properties, I get another set of settings and on the Configuration tab there is the Launch browser for flag, after unchecking it a new browser window is not opened on application start up.