How to handle "RunCommand property is not defined" issue?

Hi @AnonymousKKYY ,

Based on your image, I think the root cause was that the project was incorrectly set up as a Class Library, rather than a Console Application or Web Application, which is required for ASP.NET Core apps to run properly.

When you set the Output Type to Class Library, you're telling Visual Studio to build a DLL, not an executable. This has several implications:

• Class Libraries cannot be executed directly—they are meant to be referenced by other projects.
• ASP.NET Core applications require an entry point (like Program.cs with a Main method) to start the web server.
• The RunCommand property is used by Visual Studio and IIS Express to determine how to launch the application. Since Class Libraries don’t have a RunCommand, the system throws an error.

To resolve the issue:

1. Change the Output Type to Console Application:

In Solution Explorer, right-click on the project name > Properties > Application tab.

Set Output type to Console Application.

2. Ensure the correct SDK is used in your .csproj file:

In Solution Explorer, right-click on the project name > Select "Edit Project File". > This opens the .csproj file directly in the editor.

<Project Sdk="Microsoft.NET.Sdk.Web">
  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
  </PropertyGroup>
</Project>

Hope my solution would solve your issue.

an asp.net core application should be a console app, not a class library. also in the project file it should specify the web sdk:

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
  </PropertyGroup>

</Project>