How to convert a Class Library project to a Web Application project?

It's mentioned in the comments already, but somehow it's easy to miss (at least I missed it). If you applied Brad's solution, but your project is still missing the option to add areas, controllers and views, you still need to add an MVC project guid {E3E379DF-F4C6-4180-9B81-6769533ABE47}.

The ProjectTypeGuids line should now look like this:

<ProjectTypeGuids>{E3E379DF-F4C6-4180-9B81-6769533ABE47};{349c5851-65df-11da-9384-00065b846f21};{fae04ec0-301f-11d3-bf4b-00c04f79efbc}</ProjectTypeGuids>

As mentioned by JamesQMurphy, {FAE04EC0-301F-11D3-BF4B-00C04F79EFBC} will not work in VB projects. That's because it's a C# project guid. So for VB project a VB project guid has to be used. This guid is {F184B08F-C81C-45F6-A57F-5ABD9991F28F}.

Here is a list of some of the known project guids (taken from this site):

• ASP.NET MVC 1.0 {603C0E0B-DB56-11DC-BE95-000D561079B0}
• ASP.NET MVC 2.0 {F85E285D-A4E0-4152-9332-AB1D724D3325}
• ASP.NET MVC 3.0 {E53F8FEA-EAE0-44A6-8774-FFD645390401}
• ASP.NET MVC 4.0 {E3E379DF-F4C6-4180-9B81-6769533ABE47
• C# {FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}
• C++ {8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}
• Database {A9ACE9BB-CECE-4E62-9AA4-C7E7C5BD2124}
• Database (other project types) {4F174C21-8C12-11D0-8340-0000F80270F8}
• Deployment Cab {3EA9E505-35AC-4774-B492-AD1749C4943A}
• Deployment Merge Module {06A35CCD-C46D-44D5-987B-CF40FF872267}
• Deployment Setup {978C614F-708E-4E1A-B201-565925725DBA}
• Deployment Smart Device Cab {AB322303-2255-48EF-A496-5904EB18DA55}
• Distributed System {F135691A-BF7E-435D-8960-F99683D2D49C}
• F# {F2A71F9B-5D33-465A-A702-920D77279786}
• J# {E6FDF86B-F3D1-11D4-8576-0002A516ECE8}
• Legacy (2003) Smart Device (C#) {20D4826A-C6FA-45DB-90F4-C717570B9F32}
• Legacy (2003) Smart Device (VB.NET) {CB4CE8C6-1BDB-4DC7-A4D3-65A1999772F8}
• Model-View-Controller v2 (MVC2) {F85E285D-A4E0-4152-9332-AB1D724D3325}
• Model-View-Controller v3 (MVC3) {E53F8FEA-EAE0-44A6-8774-FFD645390401}
• Model-View-Controller v4 (MVC4) {E3E379DF-F4C6-4180-9B81-6769533ABE47}
• Mono for Android {EFBA0AD7-5A72-4C68-AF49-83D382785DCF}
• MonoTouch {6BC8ED88-2882-458C-8E55-DFD12B67127B}
• MonoTouch Binding {F5B4F3BC-B597-4E2B-B552-EF5D8A32436F}
• Portable Class Library {786C830F-07A1-408B-BD7F-6EE04809D6DB}
• SharePoint (C#) {593B0543-81F6-4436-BA1E-4747859CAAE2}
• SharePoint (VB.NET) {EC05E597-79D4-47f3-ADA0-324C4F7C7484}
• SharePoint Workflow {F8810EC1-6754-47FC-A15F-DFABD2E3FA90}
• Silverlight {A1591282-1198-4647-A2B1-27E5FF5F6F3B}
• Smart Device (C#) {4D628B5B-2FBC-4AA6-8C16-197242AEB884}
• Smart Device (VB.NET) {68B1623D-7FB9-47D8-8664-7ECEA3297D4F}
• Solution Folder {2150E333-8FDC-42A3-9474-1A3956D46DE8}
• Test {3AC096D0-A1C2-E12C-1390-A8335801FDAB}
• VB.NET {F184B08F-C81C-45F6-A57F-5ABD9991F28F}
• Visual Database Tools {C252FEB5-A946-4202-B1D4-9916A0590387}
• Visual Studio Tools for Applications (VSTA) {A860303F-1F3F-4691-B57E-529FC101A107}
• Visual Studio Tools for Office (VSTO) {BAA0C2D2-18E2-41B9-852F-F413020CAA33}
• Web Application {349C5851-65DF-11DA-9384-00065B846F21}
• Web Site {E24C65DC-7377-472B-9ABA-BC803B73C61A}
• Windows (C#) {FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}
• Windows (VB.NET) {F184B08F-C81C-45F6-A57F-5ABD9991F28F}
• Windows (Visual C++) {8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}
• Windows Communication Foundation (WCF) {3D9AD99F-2412-4246-B90B-4EAA41C64699}
• Windows Phone 8/8.1 Blank/Hub/Webview App {76F1466A-8B6D-4E39-A767-685A06062A39}
• Windows Phone 8/8.1 App (C#) {C089C8C0-30E0-4E22-80C0-CE093F111A43}
• Windows Phone 8/8.1 App (VB.NET) {DB03555F-0C8B-43BE-9FF9-57896B3C5E56}
• Windows Presentation Foundation (WPF) {60DC8134-EBA5-43B8-BCC9-BB4BC16C2548}
• Windows Store (Metro) Apps & Components {BC8A1FFA-BEE3-4634-8014-F334798102B3}
• Workflow (C#) {14822709-B5A1-4724-98CA-57A101D1B079}
• Workflow (VB.NET) {D59BE175-2ED0-4C54-BE3D-CDAA9F3214C8}
• Workflow Foundation {32F31D43-81CC-4C15-9DE6-3FC5453562B6}
• Xamarin.Android {EFBA0AD7-5A72-4C68-AF49-83D382785DCF}
• Xamarin.iOS {6BC8ED88-2882-458C-8E55-DFD12B67127B}
• XNA (Windows) {6D335F3A-9D43-41b4-9D22-F6F17C4BE596}
• XNA (XBox) {2DF5C3F4-5A5F-47a9-8E94-23B4456F55E2}
• XNA (Zune) {D399B71A-8929-442a-A9AC-8BEC78BB2433}

P.S. In case you wonder, the list is apparently public domain.

Create a new web application project in your solution and drag and drop all files from class library to the new web application project.

in .net core 3.1 modify the project file [project name].csproj and change

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

to

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

now save changes and reload the project, now you have a web app (MVC) project.

I did this by hand today in Visual Studio 2005 because it seemed easier and faster than the above. I just diffed a working web application .csproj file with my class library to determine the relevant differences. Based on that, I made the following changes. Keep in mind that it may be different for other versions or your individual project.

1) Right after the <ProjectGuid> element near the top, I added

<ProjectTypeGuids>{349c5851-65df-11da-9384-00065b846f21};{fae04ec0-301f-11d3-bf4b-00c04f79efbc}</ProjectTypeGuids> 

2) I removed <ProjectType>Local</ProjectType>
3) At the bottom of the file, right before the closing </Project>, I added

<Import Project="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v8.0\WebApplications\Microsoft.WebApplication.targets" />
      <ProjectExtensions>
        <VisualStudio>
          <FlavorProperties GUID="{349c5851-65df-11da-9384-00065b846f21}">
            <WebProjectProperties>
              <UseIIS>False</UseIIS>
              <AutoAssignPort>True</AutoAssignPort>
              <DevelopmentServerPort>3291</DevelopmentServerPort>
              <DevelopmentServerVPath>/</DevelopmentServerVPath>
              <IISUrl>
              </IISUrl>
              <NTLMAuthentication>False</NTLMAuthentication>
            </WebProjectProperties>
          </FlavorProperties>
        </VisualStudio>
</ProjectExtensions>