I know there are a lot of problems like that and you all might think this is a duplicate but NO... this problem is different.
When I add a custom user control to a project and rebuild it, the control is added to the toolbox. If I try to add another one it does not show up in the toolbox. If I close visual studio and reopen it the first control also was removed from the toolbox and will never appear again. From now on the project is broken and no control added, remove + readded will ever show up in the toolbox. So I create a new project and it starts from the beginning.
Before this tip appears I'll say it: Automatically Populate Toolbox is True. Nothing helps against this problem. Build Project/Solution, Rebuild, Clean+Rebuild, Restart of VS, Restart of Computer, Unload and reload the project, set toolbox back to default. Nothing works.
Any ideas??
You have to remember that the designer call your code constructor and some other methods at design time.
If you build the code and the control does not appears and it has not been hidden by an attribute, then probably the code you wrote is not compatible with the designer. For example, the control might throw an exception in design mode because of incorrect code.
The attribute is [ToolboxItem(false)]. If you have a base class that hide it, it will also be hidden in derived class if not specified otherwise.
You will have the same problem if that control is used in another component. You won't see it if it does not compile and run correctly.
The trick to debug that kind of problem, is to attach a debugger from a second instance of Visual Studio to find where in your code you throw an exception.
If the control does not work at run-time, better to fix that first as if it also fix design problem, it is simpler to debug that way.
Otherwise, you have to ensure that your project dependencies are correct. The toolbox will only shows component from DLLs that are referenced by the current project (or from itself I think).
We have a Windows Forms application used for testing our products that has had pretty much the same forms and dialogs for nearly 10 years now. AutoScaleMode in the designer is set to Font for both forms, and that hasn't changed since the original design. AutoSize is set to false and just for good measure (I guess) AutoSizeMode is set to GrowOnly. The following source lines are in Program.cs:
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Remember, this has been working flawlessly for years...
One of the recent updates to VS2017 included AutoScale support for monitors with different DPI. I have a relatively high DPI monitor, so when I made some changes to a Settings dialog (adding controls, etc) I started getting bright yellow banners cross the top of the designer surface telling me that AutoScaling was set to 125%, and would I like to change that? I tried going back and forth, and when in 100% mode (Autoscaling off) I was warned that XAML forms might not display correctly. Fine, I am working with Forms so I went back to "normal" scaling and the form looked fine.
Until I tried running the program. Now when I start the program the main form looks like this (details deleted to protect the guilty):
...but when I open the settings dialog it looks like this:
Yikes! It looks worse in practice, the relative images here don't do justice to the difference in size and scale.
I have no idea what got changed or how / why this is happening, but there's no way I can put this into production. I've tried changing the AutoScale settings, to no avail. Can somebody point me in the right direction here?
Thanks in advance!
EDIT: It seems the rescaling only happens on my machine when I run the app in Debug. Whatever is messing up the display of the forms on my machine doesn't do that on my associates' machines and isn't replicated to the executable produced by the build server.
On another note, I tried every DPI-related setting I could find, added those that weren't there due to the program's age, all to no avail. Nothing I have tried has had any effect on the program's display weirdness on my machine. Ugh.
I tried all the tricks I could find, short of disabling AutoScale completely, and nothing worked. I finally merged our develop branch in to my feature branch and inspected all 270 edits, choosing the oldest settings I could find for all size parameters, all controls. Ugh.
Along the way I stumbled across the following line in the Designer.cs file for the form:
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
This setting is NOT accessible from Visual Studio's designer, as far as I can tell, nor can I find anything about how or why it gets set. What I did find was that in the earlier version that did work as expected, the values were (8F, 17F) -- so I manually edited the line to match the older, working version. Success!
I also checked my Windows display settings, and the Custom Scaling value was at 100%, so I used the registry hack mentioned in one of the articles I found following the first link from the comment above (thanks, #Jimi) to disable auto-scaling in Visual Studio, then turned off the notification. Now I'm (finally) back in business.
Registry hack is here:
https://learn.microsoft.com/en-us/dotnet/framework/winforms/disable-dpi-awareness-visual-studio
If one uses the registry hack mentioned in the answer from DaveN59, and there is already entry for your ...\devenv.exe (mine was previously set to run as admin) then add the DPIUNAWARE string to the end of the "Data". Make sure to use a space as a separator.
Example: ^ RUNASADMIN DPIUNAWARE
I'm not sure what the ^ is for, but it was there and I just added DPIUNAWARE string. Also, if you just add this string, it will come up unscaled, but you will still see the yellow banner. To turn that off you'll need to select that option from with in Visual Studio. The instructions are in the link for the registry hack, also provided above. For conveinece here's the menu navigation path.
To disable notifications, choose Tools > Options to open the Options
dialog. Then, choose Windows Forms Designer > General, and set DPI
Scaling Notifications to False.
I'm using thbe Microsoft Ribbon for WPF (System.Windows.Controls.Ribbon) and VS2015. Since I removed unnecessary depencies from my project (like Dynamic Data Display etc, things not related to the ribbon) it does not render correctly in the Designer anymore. All RibbonButtons get rendered as usual buttons and so on.
I used the Clean Solution option and also rebuild multiple times, without sucess. While execution everything is fine, just the designer can't handle the ribbon anymore. What could have caused this strange behaviour?
This is how my ribbon looks now in the designer:
And this is how it's supposed to look and looked before:
Update: it clearly seems to be a visual studio bug, as I opened the project on another machine with the same VS version and there everything is fine.
deleting %LOCALAPPDATA%\Microsoft\VisualStudio\14.0\Designer\ShadowCache wasn't working but this:
close solution (at best every instance of VS, you never know)
delete bin\ and obj\ in solution folder ("Clean Solution" isn't enough nowadays. Why should it? It isn't anything anyone would ever do if VS is doing strange things. Maybe I should fall back to kill -9 devenv.exe && git clean -fX as default m( )
Reopen solution and hope for the best.
This drove me nuts. The only real google hits for this problem was this SO question, another one without any answer, 500+ pseudomirrors of SO and thousands of false positives... sorry for the rant.
The problem was resolved by clearing the Visual Studio Designer Cache.
This is done by deleting the subfolders in %LOCALAPPDATA%\Microsoft\VisualStudio\14.0\Designer\ShadowCache
I am stumped on this one. I am not sure if others are having the same issue.
In past versions, when I use the report wizard, one of the screens lets me choose the style (Slate, Forest...)
With my new setup the screen never appears and on the summary screen it says 'Style:Modern'
I tracked down the StyleTemplate.Xml, made a copy and changed 'Modern' to 'ModernTest'. Both in the Styles folder and the en folder. I have searched my c drive and these are the only two places this file exists.
EDIT: I had to change the label to 'ModernTest' not the name. Now 'ModernTest' is showing up in the summary. I still however do not get the chance to change styles.
I added a new style to see if the page only shows up if more than one is present but maybe since that one was from an older version it still only thinks there is one valid style so skips the selection page... I will try to replicate modern...
I am using VS2015 Version 14.0.25123.00 Update 2, SSDT Version 14.0.1601.5
Anyone else have the same issue?
EDIT: I copied an xml file from a previous version and now slate appears as the style. I guess the only problem is that the screen to select the style no longer shows up.
I am using using VS2010 and if I have a form open in designer mode and run my application the designer tab will no longer show the form designer but instead an error will be displayed (and it is only fixed by restarting the IDE) saying:
"To prevent possible data loss before loading the designer, the
following errors must be resolved:"
1 Error:
"The designer could not be shown for this file because none of the
classes within it can be designed. The designer inspected the
following classes in the file: ##### --- The base class ##### could
not be loaded. Ensure the assembly has been referenced and that all
projects have been built"
I then shows the following call stack:
at System.ComponentModel.Design.Serialization.CodeDomDesignerLoader.EnsureDocument(IDesignerSerializationManager manager)
at System.ComponentModel.Design.Serialization.CodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager manager)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager serializationManager)
at System.ComponentModel.Design.Serialization.BasicDesignerLoader.BeginLoad(IDesignerLoaderHost host)
Any help is greatly appreciated this is really annoying.
Thanks,
Joel.
I get this visual studio bug too now and then, and I deeply ignore the error text, instead I do the following:
Close the Design-tab
Reopens the Design mode by double click in Solution Explorer, or by right clicking Source code tab and select View Designer
Suddenly everything works again!
If not helping, you may have to change bullet 2 into:
Close and restart Visual Studio.
Maybe this can help you out.
I usually close the visual form, rebuild the solution, right-click then select "view designer" in the form code.
Very, very annoying. I am thinking of dropping back to VS2008.
Close the form. Clean the solution. Rebuild the solution. Reopen the form. Worked for me when nothing else would.
I had this same issue and I was able to resolve this by creating new project and then compiled and run the project and then I imported all the files and ran the project again and automatically it was working again did nothing extra.
I'm able to avoid restarting VS by doing the following
Add a new user control
Drag and drop some of your custom user controls on to it (If it gives you an error, build the solution again).
Reopen your control.
In my case, I have a winforms project with several custom controls that are used by other custom controls. Whenever I open some of those custom controls, I get a the "The base class ..." error. Adding a new custom control, building the project and then adding some custom controls from my project to the new custom control allowed me to open the custom controls that were giving me the "The base class ..." error.
UPDATE: I think I found the problem. My controls were not 'added' properly to the csproj file. In the csproj file, the files for partial classes of UI controls/components need the 'DependentUpon' attribute.
E.x.:
before:
<Compile Include="Windows\Forms\DataGridView.cs">
<SubType>Component</SubType>
</Compile>
<Compile Include="Windows\Forms\DataGridView.Designer.cs" />
after:
<Compile Include="Windows\Forms\DataGridView.cs">
<SubType>Component</SubType>
</Compile>
<Compile Include="Windows\Forms\DataGridView.Designer.cs">
<DependentUpon>DataGridView.cs</DependentUpon>
</Compile>
I had a situation where a custom user control appeared to be creating the error (not sure why) so I removed references to the user control from the form and the error went away.
It seems that after installing SP1 the problem has gone away.
Thanks for your help everyone.
I had the same problem using A control With Generics
MvpUserControl<Presenter,IViewMode> : UserControl
what I do it's Remove the Reference and Add again, Clean and Rebuild the Solution I Hope this can be useful for anybody else
I had the same problem with VS2010 SP1. Finally using Windows Update I saw some updates for Visual Studio and .Net, I installed them and is not happening any more.
Old post, but for those whom may find this...
Just ran in to this error and for me it was relatively simple fix.
Found that it may have something to do with the names of your classes, and renaming the problematic class to a higher order. That is the alphabetical order it appears in the assembly (Where A is higher than Z).
MSDN Article
Good luck.
This error occur if the Form class is not a first class in the file, for example if there is some helper class at the beginning of the file.
To solve this issue, move all other classes except Form class to the bottom of the file.
Don't code in Form1.Designer.cs. Move your logic to Form1.cs (hit F7 on Form1.cs [Design] tab).
"In the project file (.vcxproj), locate the entry for the target
Framework version. For example, if your project is designed to use the
.NET Framework 4.5, locate
v4.5 in the
element of the element. "
(Microsoft)
In my case the "v4.5" didn't exist so I add it, and everything is good now.
I tried clean solution and re-build solution and worked for me.
Hope this help!
This solution works fine, please follow these steps below to solve your problem:
Check the reference if load correctly
Clean the solution and rebuild again
Clean the project and rebuild again
Clean your project and open it again
I was login as administrator in visual studio . I just close my visual studio and again open it without run as administrator and my problem is solved
I ran into this today after upgrading VS2019. I went to properties, configuration tab, and set the projects to Configuration = Debug, Platform = Any CPU. Then it worked.
I faced this issue.
To prevent possible data loss before loading the designer, the following errors must be resolved:
I found solution for this problem:
Close all open tabs, and refresh (sync active documents) the solution.
For more information, you can see this video : https://youtu.be/Q3x2HBd7BDs