### *Fix*: Update to the latest version of Visual Studio 2017 - 15.9.19+

[![enter image description here][1]][1]

It appears this was only a problem for `.vbproj` project types. 

This was also reported in:

* the [dotnet/project-system github repo issues](https://github.com/dotnet/project-system/issues/4751)
* this Developer Community issue on the [Project Properties Build Page Blank](https://developercommunity.visualstudio.com/content/problem/460020/project-properties-build-page-blank.html)




  [1]: https://i.stack.imgur.com/RFrrw.png

When trying to open the Properties of a WPF application, on the Application page, it gives the following error: 

> An error occurred trying to load the page. The method or operation is not implemented.

[![screenshot][1]][1]

In the Windows Event Viewer I  can find this:

```none
Error Information 
AppInsightsEvent Name = vs/ml/proppages/appdesigner/prop-page-designer-view-fault
Description           = ActivatePage
TelemetrySession      = '4a288b83-00d2-4f45-84cf-513352811580' Started = True OptIn=True IsInitialized = True Cloned = False
WatsonEventType       = VisualStudioNonFatalErrors2
UTC time              = 2019-03-07T10:27:40

Exception:  System.NotImplementedException  
The method or operation is not implemented. 

Microsoft.VisualStudio.Editors.PropertyPages.WPF.ApplicationPropPageVBWPF.StartupObjectOrUri.GetHashCode()
System.Collections.Hashtable.GetHash(Object key) 
System.Collections.Hashtable.InitHash(Object key, Int32 hashsize, UInt32& seed, UInt32& incr) 
System.Collections.Hashtable.ContainsKey(Object key) 
System.Windows.Forms.ComboBox.ComboBoxItemAccessibleObjectCollection.get_Item(Object key) 
System.Windows.Forms.ComboBox.ComboBoxUiaProvider.SetComboBoxItemSelection()
System.Windows.Forms.ComboBox.OnSelectedIndexChanged(EventArgs e) 
System.Windows.Forms.ComboBox.set_SelectedIndex(Int32 value) 
System.Windows.Forms.ComboBox.set_SelectedItem(Object value) 
Microsoft.VisualStudio.Editors.PropertyPages.WPF.ApplicationPropPageVBWPF.SetSelectedStartupObjectOrUriIntoCombobox(ComboBox combobox, StartupObjectOrUri startupObjectOrUri) 
Microsoft.VisualStudio.Editors.PropertyPages.WPF.ApplicationPropPageVBWPF.SetStartupObjectOrUriIntoUI(Control control, PropertyDescriptor prop, Object value) 
Microsoft.VisualStudio.Editors.PropertyPages.PropertyControlData.InitPropertyUI()
Microsoft.VisualStudio.Editors.PropertyPages.PropPageUserControlBase.InitPage()
Microsoft.VisualStudio.Editors.PropertyPages.PropPageUserControlBase.SetObjects(Object[] objects) 
Microsoft.VisualStudio.Editors.PropertyPages.PropPageUserControlBase.IPropertyPageInternal_SetObjects(Object[] objects) 
Microsoft.VisualStudio.Editors.PropertyPages.PropPageBase.Create(IntPtr hWndParent) 
Microsoft.VisualStudio.Editors.PropertyPages.PropPageBase.IPropertyPage2_Activate(IntPtr hWndParent, RECT[] pRect, Int32 bModal) 
Microsoft.VisualStudio.Editors.PropPageDesigner.PropPageDesignerView.ActivatePage(IPropertyPage PropPage)
```

## What I've Tried

* I previously installed the Visual Studio 2019 RC, but have now uninstalled it. That version also gave the same error.  
* Reinstalling Visual Studio 2017 didn't help.
* This happens in old and freshly created projects.
* My coworker doesn't have this on his computer with the same projects.
* I did not have any problems last week. I haven't installed/uninstalled anything special.


  [1]: https://i.stack.imgur.com/wX0uB.png

Error when trying to view the Application Properties page in Visual Studio 2017

### Try any of the following fixes....

1. **Clean + Rebuild Solution**
2. **Restart Visual Studio**
3. **Run Visual Studio as Admin**
4. **Restart Computer**
5. **Launch Without Debugging**
 <kbd>Ctrl</kbd> + <kbd>F5</kbd>

6. **Step Into Debugging** 
 Hit <kbd>F11</kbd> to start debugging by stepping into the first line of executed code. If that works, the problem is likely in your code somewhere (possibly an *ehem* StackOverflow Exception)

 [![Step Into][1]][1]

 [![Breakpoint on Application_Start][2]][2] 


7. **Break on CLR Exceptions** 
 If there is a problem with the code on startup, you should break when thrown 
 Go to Debug > Windows > Exception Settings (<kbd>Ctrl</kbd> + <kbd>Alt</kbd> + <kbd>D</kbd>) 
 Select `Common Language Runtime Exceptions`

 [![Exception Settings][3]][3]

 [![Common Language Runtime Exceptions][4]][4] 


8. **Change Project Port** 
 Go to Project > Properties > Web > Project URL 
 Try using **`8080`**, but any change might work

 [![Web Settings > URL > Port][5]][5] 


9. **Create Virtual Directory** 
 In the above screenshot, select `Create Virtual Directory` to the right of the Project Url 

10. **Delete `.vs` folder** 
 Open the Directory where the solution / project lives. 
 Make sure *hidden* file are visible, and delete the `.vs` folder

 [![Delete .vs folder][6]][6] 


11. **Restart IIS Express** 
 In the system tray, right click on IIS Express and select Exit

 [![Exit IIS Express][7]][7] 


12. **Enable 64 Bit IIS Express** 
 ***If** you're on a 64 bit machine*... 
 Go to Tools > Options > Projects and Solutions > Web Projects 
 Select `Use the 64 bit version of IIS Express...` 
 

 [![Use the 64 bit version of IIS Express][8]][8] 

13. **Check Event Viewer** 
 Check for any additional diagnostic information in Event Viewer under Windows Logs > Application

 [![Event Viewer][9]][9]

 [![Windows Logs > Application > IIS Express][10]][10] 

14. **Run IIS Express from cmd line** 
 You can rule out if there's an issue with Visual Studio or your Web Project itself. 
 Here's the docs on [Running IIS Express from the Command Line][11] 
 Pass in the path to the root of your project (where the web.config) is located

 ```bash
 > "C:\Program Files (x86)\IIS Express\iisexpress.exe" /path:C:\repos\project\
 ```
 

15. **Download IIS Express** 
 Get the standalone installer for [Internet Information Services (IIS) 10.0 Express][12] and try again 

16. **Disable Edit and Continue** 
 Go to Project > Properties > Web > Debuggers 
 Deselect `Enable Edit and Continue` although this will remove that functionality

 [![Disable Edit and Continue][13]][13] 

### Further Reading: 

* [ASP.NET MVC5/IIS Express unable to debug - Code Not Running][14]
* [IIS Express crashes when starting a site from visual studio][15]
* [Unable to launch IIS Express Web server][16]


 [1]: https://i.stack.imgur.com/LDQJO.png
 [2]: https://i.stack.imgur.com/pdWja.png
 [3]: https://i.stack.imgur.com/KPs8R.png
 [4]: https://i.stack.imgur.com/cpjCc.png
 [5]: https://i.stack.imgur.com/F7LSt.png
 [6]: https://i.stack.imgur.com/0kMOn.png
 [7]: https://i.stack.imgur.com/V5Cg6.png
 [8]: https://i.stack.imgur.com/j6UG0.png
 [9]: https://i.stack.imgur.com/0sxyb.png
 [10]: https://i.stack.imgur.com/Opl08.png
 [11]: https://learn.microsoft.com/en-us/iis/extensions/using-iis-express/running-iis-express-from-the-command-line
 [12]: https://www.microsoft.com/en-us/download/details.aspx?id=48264
 [13]: https://i.stack.imgur.com/zIO4f.png
 [14]: https://stackoverflow.com/q/19472682/1366033
 [15]: https://stackoverflow.com/q/30406261/1366033
 [16]: https://stackoverflow.com/q/45480722/1366033

When running my solution in debug mode, IIS Express and Internet Explorer as the browser, I get the following error: 

```none
The program '[12604] iisexpress.exe: Program Trace' has exited with code 0 (0x0).
The program '[12604] iisexpress.exe' has exited with code 0 (0x0).
```

I'm using Visual Studio 2017.  If I change to Chrome, I do not get this. 

The only way to resolve this and still use IISExpress and IE is to go into my properties of the web project and uncheck **Enable Edit and Continue** under Debuggers.  

Any idea as to why? 

The program '[12604] iisexpress.exe' has exited with code 0 (0x0)

I can't share the entire codebase to reproduce the issue, but I'm using [Visual Studio Diagnostic Tools][0] to inspect performance and operations are taking many times longer to execute that what's getting reported in CPU usage.

### Example Code

Here's an example of the offending block of code between two breakpoints:

[![Diagnostic Entry Point][1]][1]

### Profiling Time

The CPU samples inside this method only suggest it's spending about **1000 ms** to execute:

[![CPU Usage][2]][2]

[![Caller Callee][3]][3]

[![Profile][4l]][4f]

### Execution Time

However, it takes nearly **50 seconds** between breakpoints

[![Diagnostic Timeline][5]][5]

### Question

* What could cause such a long execution timeline that doesn't show up when profiling?

### Things I've Tried:

* Restarting VS
* Restarting Machine
* Reloading Symbols
* Caching Symbols

  [0]: https://learn.microsoft.com/en-us/visualstudio/profiling/profiling-feature-tour
  [1]: https://i.stack.imgur.com/qbv0D.png
  [2]: https://i.stack.imgur.com/jmFgE.png
  [3]: https://i.stack.imgur.com/cirQu.png
  [4f]: https://i.stack.imgur.com/qLQpL.png
  [4l]: https://i.stack.imgur.com/qLQpLl.png
  [5]: https://i.stack.imgur.com/ppghx.png