1. 确认项目已安装.net核心2.1或更高版本，可以在项目文件中查看：netcoreapp2.1
2. 在项目的launchSettings.json文件中，确认WebAssembly的配置项为正确的应用程序名称，并选择正确的启动URL： "BlazorWasm": { "commandName": "Project", "dotnetRunMessages": "true", "environmentVariables": { "ASPNETCORE_ENVIRONMENT": "Development" }, "applicationUrl": "https://localhost:44367;http://localhost:5050", "launchBrowser": true, "launchUrl": "BlazorWasm" }
3. 在Rider中打开项目并选中“Wasm”项目，单击调试按钮，即可开始调试Blazor WASM应用程序。

附加参考：https://rider-support.jetbrains.com/hc/en-us/community/posts/360008657280-Blazor-WASM-does-not-debug-on-Rider