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.

.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)。

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.

对于VS2022和ASP。NET核心:

另一个快捷方式是:单击右边绿色三角形按钮上的小下拉按钮，上面有项目名称，这通常会启动调试版本。然后是最后一个选项“{项目名}调试属性”，它直接启动专用的UI窗口。

从那里遵循@irf的建议:

“uncheck”选项不自动打开。

VS 15.7.1工具→选项→项目和解决方案→Web项目→取消勾选关闭浏览器窗口时停止调试器。

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.