I have no clue how long this feature/option has been around but my mouse happened to pause over this button within the WPF designer early and now I'm curious what it's purpose is.
Hovering over the button, Visual Studio pops up a tooltip that says Enable project code. When I click on it, the designer seems to reload the xaml contents but I can't tell what's changed.
What does this feature do?
2020 EDIT
It's been years since I've had to work in XAML, but I've received a new project where I need to work in XAML. This feature/button seems to have disappeared. Where has it migrated?
What does this feature do?
It enables or prevents the designer from running your code in the background.
Disabling project code can lead to a loss of design time data and enabling it can lead to unhandled exceptions in the XAML designer.
These exceptions are usually caused by code that attempts to access properties or methods which work differently when your application is running in the designer compared to when it runs as a built executable.
Debugging or Disabling Project Code in XAML Designer: https://msdn.microsoft.com/en-us/library/mt622752.aspx?f=255&MSPPError=-2147217396
I have a serious problem with Visual Studio 2012 XAML Designer that hangs often in these situations:
Editing in designer and then edit a value in text editor or vice versa (often)
Copy/paste operations (in text editor, specially with ResourceDictionary items) (very often)
Change to another XAML document (unusual)
The only solution I have is killing xdesproc.exe process in Task Manager (if I don't do this, it would take over 15 minutes to be working again), but if I have a lot of XAML files opened I need to reload the designer wasting some time because the text editor hangs too when is loading.
Is very annoying, and I didn't have this problem with Visual Studio 2010.
What could be a viable solution for this issue?
http://social.msdn.microsoft.com/Forums/en-US/cb7d638b-64ea-4e5a-b926-081b6abf1e58/xaml-editor-in-vs-2012-is-really-slow-and-locks-up-a-lot -googled a bit and found this
Has anyone else experience incredibly slow performance in the XAML editor in VS 2010? If I have a new project with a limited number of files, the performance is fine. However, if I have a project with a larger number of XAML files, the XAML editor hangs intermittently every few seconds, making it almost impossible to use.
I should also note that the performance is only slow in one particular project where I am referencing DevExpress 2010. I am not certain if this is related.
Any suggestions on solutions to this problem would be greatly appreciated.
Chris
In Visual Studio 2012:
Go to
Tools > Options > TextEditor > XAML > Misc
Check Always open documents in XAML view and uncheck Automatically populate toolbox items.
In Visual Studio 2015, 2017:
Go to
Tools > Options > XAML Designer
uncheck Automatically populate toolbox items.
This fixed my same problem.
If you don't need the visual designer, you can select a different editor in visual studio:
Right click the xaml file -> Open With... -> Source Code (Text) Editor
You will only lose the split view, intellisense etc. should still work.
If you need to check something in the designer you can still click 'view designer' to open the normal XAML editor again.
If you want to improve the performance of the visual designer, try checking DesignerProperties.GetIsInDesignMode in your code-behind. The visualiser instantiates your controls to know how to display them, thus executing parts of the code-behind.
Like the OP, I had extreme lag in the xaml editor on a project that relied heavily on DevExpress WPF controls. After trying unsuccessfully to resolve this issue with the other solutions posted here, I eventually tried deleting my Solution User Options (.suo) file, which is usually located in the same folder as the solution (.sln) file. This immediately resolved the issue. You may want to read this post about what visual studio stores in the suo file so you can reset anything important (such as build configuration - mine always defaults the active solution platform back to "Mixed Platforms" for example)
Short answer: if you do not use designer much, just replace the default editor for XAML, thus getting rid of XAML visual designer and speeding things up. Right click any XAML file, click Open with... and choose another default editor. Source code (text) editor works just fine.
Now it should be already fine. If you want to understand the details and completely get rid of the slow designer, read the long answer.
Long answer: Here is a nice explanation of what happens and why is it that slow.
A brief todo based on the aforementioned article in order to completely disable the visual designer of XAML:
Under Tools->Options->Text Editor->XAML->Miscellaneous->Default View check Always open documents in full XAML view
Open Task manager and end XAML Designer process XDesProc.exe (Note: for VS2013 right click this process and go to containing folder. Rename the exe to sth else, than end the process)
Standard XAML editor will load this process again (I guess it will not succeed with VS2013 and actions done in P.2). However, right click any XAML file, Open with... and choose another default editor. Source code (text) editor works just fine.
While using dev express, I've noticed some laggy response in the Visual Studio designer. This appears to be due to the license authentication of the DevExpress products.
If you delete the "Licenses.Licx" file (found in the project properties folder) you'll notice a marked improvement in performance.
Note: Removing the license file doesn't stop you from using DevExpress controls. But it does stop VS from constantly authenticating it.
Is there any way to force the WPF designer to reload or refresh, without rebuilding the entire project or solution?
If there's an error, I get an option in the designer view to refresh the designer. But if I don't have an error, how can I get the designer to refresh after I've made a change?
I'm a little late but this is the best solution1 I've found so far: whenever the designer does stupid stuff, I just kill it's process.
Press Ctrl+Shift+Esc
Navigate to the Processes tab.
Kill XDesProc.exe
This also fixes issues for the properties window (like when it gets jammed and you can't type stuff into it).
1 This is a solution for designer issues. Your issues may also be caused by compilation problems, in which case just right click on the solution in the solution explorer, and clean it. The reason behind it is that sometimes the compilation loses synchronicity with the generated files from XAML, and cleaning the solution just deletes those intermediate files; it's like a reset so your compilation can start off with a clean slate.
To do it fast:
Comfortably it's usually the last one if sorted alphabetically.
When it is, it's almost like a ritual for me to quickly pop up the task manager, click any process, press End, Delete, Enter (done), Esc (exit task manager). Instead of restarting VS and waiting for all the loads & unloads, you can do that in 1-2 seconds.
In newer versions of Visual Studio there is an icon on the bottom of the designer to "Disable Project code". If you toggle this off and on it will reload the designer.
You can add this to the Tools menu in Visual Studio.
Once configured, use Tools..XAML Designer Restart:
Alt+T then L
I tried configuring it for Alt+T then X but this clashed with Tools..Choose ToolboX Items.
Update
These days, I prefer to just hit Ctrl+Shift+Esc to bring up the process manager, then X to skip to XDesProc.exe then Delete to kill the rogue process(es).
The Visual Studio designer attempts to keep the rendered view in sync with the XAML. That's the advertised behavior.
The first thing you should check is that there are no errors in the errors window. It may be something as simple as a missing angle bracket.
The second thing to check is whether you have any code (other than your code-behind) which needs to be compiled for the designer to render your XAML correctly. This includes any of your own datatypes that you instantiate in XAML, any custom controls you have written (e.g. MyTextBlock derived from TextBlock), or any classes directly or indirectly in support of design-time data. If so, you need to rebuild your project.
The last thing to check for is possible bugs in the designer. In spite of the advertised behavior, the designer may get out-of-sync due to bugs. In that close, close the XAML window and re-open it. Other tricks that might work are selecting the XAML tab and then the Design tab, or maximizing the XAML pane.
As far as rebuilding your application goes, you don't need to do this as a habit. You only need to recompile it when the above conditions apply. Once they don't apply, you can just edit the XAML. Another way to say this is that if you haven't modified code, you shouldn't need to rebuild (modulo bugs).
I'm not sure, but I think a build will refresh your view in that situation.
There is any event handled in that XAML file, then mostly it will not display the design preview from Visual Studio. If you want to see the design from Visual Studio, try with Command Binding instead of event, you will see the preview.
I'm not sure how this works in WPF editing, but with ASP.NET pages when the design view wont update i can do 2 things
Exit Visual Studio and restart
Go into source view (not split), type something and remove it (not by undoing, just delete or backspare) and save it. Then return to design view, usually the view has been updated then.
When you add a new row of code or a new object, XAML designer is sync but I encountered non-sync behavior when a property of an object is changed.
A tricky way is that when you change a property you only need to remove a ">" character from end of an instruction then retype it.
On the toolbar in the XAML designer, choose the "Disable project code" button to reload the designer link which stays on the right side of "Turn on snapping to snaplines".
Disable project code in the designer
If it is disabled, you can try to check the configuration manager and change processors to "Any CPU".
For projects that target ARM or X64 processors, Visual Studio cannot run project code in the designer, so the Disable project code button is disabled in the designer. Check this:
Debug or disable project code in XAML Designer
For information, I had the same issue with the XAML Designer of Visual Studio Community 2017, i.e. sometimes the designer doesn't show anything, the easiest solution is then to close the XAML file and reopen it.
I also frequently get the exception "An Unhandled Exception has occurred - Click here to reload the designer - Details: The XAML Designer has exited unexpectedly" (the click restarts the designer successfully).
Note that, in this VS version, the process of the XAML designer is not named XDesProc.exe, but UwpSurface.exe. If you prefer or have to kill the process, then the designer shows the same exception as above, and you may restart it.
use process hacker and kill the WpfSurface process (blend only)
Update for designer refresh/reload Visual Studio 2022 Xamarin, taskkill /IM java.exe
Is there a way to debug Visual Studio or Blend so I can figure out where XAML designer load errors come from in my code?
The stack traces are often useless.
Thanks...
Use two VS2010 instances. Load one with your main app probject or a test harness application project and load the other with your controls project. Having built the controls project reference the debug dlls in your other project. Debugging from the VS2010 instance holding the controls project attach to the VS2010 instance holding the test application.
Place your break points as you like.
Now drive the test application instance of VS2010 as you would when building yout controls into an application, when your controls are load their code will execute and you can start stepping the code. You can do a similar thing when working with your controls in Blend just attach to the Blend instance.
In VS, first go to Debug->Exceptions and check the box for "Thrown" for CLR Exceptions. This will break into the debugger for exceptions caught by the Blend/VS app. Then do Debug->Attach To Process... and find the instance of Blend or devenv that has your solution open. Once the debugger starts up you can open the XAML file in the designer and debug against it.
Here are another two cents. Just make sure that the Options->Debugging->General->Enable Just My Code is unchecked in the instance you are using to attach to the designer's process.
I found both answers useful. Just adding my 2 cents - In the VS copy that you're using to attach to the designer, I needed to select the code type manually (Managed, v4.0 in my example) in the Attach To Process dialog to get the desired result. For some reason the default for devenv was Script, T-SQL. Looking at the date of the OP and original answers, it may be that an update to VS caused this change... just speculating.