When dragging a control from the toolbox and dropping it in the Windows Forms designer, a message box appears with the message Object reference not set to an instance of an object.
After closing the message box, I can drop the control on the form without any other issue.
This happens on a new project as well. The error appears in both VS 2015 and 2017 (both community editions).
EDIT : This happens on any control, including custom ones. This started happening after I updated to the latest version of Windows 10 (17134.48).
Instead of dragging and dropping, Clicking on the control, then clicking on the form is the workaround working for me until they come out with a newer update.
This is new behavior as of Visual Studio 2017 Version 15.8.6 for me.
Hopefully this will help others that just kept dragging and dropping over and over like I was doing :-)
Experiencing the same issue on Microsoft Visual Studio Community 2019 Version 16.5.0. I found that I was not able to drag and drop controls while VS was open on my high DPI external monitor, but if I moved VS to my native laptop monitor, I was able to drag and drop the controls.
For Visual Studio 2017 I did not fix the problem, but I found a workaround:
went to C:\Users\user.name\AppData\Local\Microsoft\VisualStudio\15.0_e3603226
deleted all *.tbd, privateregistry.bin*, ApplicationPrivateSettings.xml files
deleted all files in ComponentModelCache folder
restarted Visual Studio as Administrator
it showed a message of updating the MEF files
drag and drop is NOT working. It keeps throwing the same error
BUT I can click on the item I want in the toolbox and then click on the designer without dragging and it works.
For Visual Studio 2015 I did not fix the problem, but I found a workaround:
went to C:\Users\user.name\AppData\Local\Microsoft\VisualStudio\14.0
deleted all *.tbd, *.lock, devenv.exe.config files
deleted all files in ComponentModelCache folder
restarted Visual Studio as Administrator
drag and drop is NOT working. It keeps throwing the same error
BUT I can click on the item I want in the toolbox and then click on the designer without dragging and it works.
I have also seen the same problem repeated today in Visual Studio 2019 (Today is June 27 2019). I am trying out the VS 2017 solution from CristisS (above). I have verified that the 'workaround' still throws the exception, however, you can immediately draw the tool onto the form.
I repeatedly run into the same issue. Seems to always be caused by running the Windows Forms designer on my secondary monitor. I don't know what causes it to misbehave, but moving Windows Forms Designer window back to my laptop screen always fixes the issue. Idk if it has something to do with scaling, or what, but it is a very repeatable issue that needs to be addressed.
Moving Visual Studio over from my hi res secondary monitor to my primary laptop monitor did fix the issue.
To use Visual Studio on my larger secondary monitor, I set my secondary monitor from 3840x2160 down to 2560x1440 and set scaling from 150% down to 100%
This lets me Drag and drop from the toolbox to the designer in Visual Studio 2019 (V16.11.3) without issue again.
I found two solutions, to this problem that they worked for my WPF project in VS2015
solution 1) Click on the icon "enable/disable project code" in the bottom of windows design(the last icon near the percentual of zoom)-->Put Disable.
solution 2) Dx mouse button on your file .xaml and apply your modify in blend , selecting the "Open in Blend..." menu.
That's all
Daniel.
I'm starting to develop apps on Xamarin, with Visual Studio 2017. As on WPF, there is a 'designer' window for the axml, with the view of the app itself, and a 'source' window with the xml describing the view.
My question is - can I split the windows so one will be above the other, just like as in WPF? Right now I can either view the designer or the source window.
Below are the wanted situation, and the current one. Thanks!
As far as I know, there isn't support to achieve that in Xamarin.Android on Visual Studio 2017.
Event if you try to use the split view and place the design in your left side you can't put the source in your right.
I know it could be overkill but most of the times I use Android Studio to draw my layouts. Since it support viewing the source and designer.
The split view designer feature for Xamarin Android has finally been added in the VS 2017 version 15.8 update. Here is a link to the release notes.
https://learn.microsoft.com/en-us/visualstudio/releasenotes/vs2017-relnotes
Android Designer Split View
Is it useful, and how can I toggle it on/off? I would just google it, unfortunately "thing at top of screen in WPF" doesn't really turn up anything useful.
It is a new WPF debugger tool found in Visual Studio 2015 Update 2. It shows the live visual tree which can be very helpful for debugging WPF applications.
You can find the feature in this changelog: https://www.visualstudio.com/en-us/news/vs2015-update2-vs.aspx
Edit: To disable this, click the left-most button in the dropdown, and then click the left-most button on the resulting live visual tree panel.
First of all, I am completely new to Visual Studio, so please don't be too judgmental. I have a project I need to do in C# for my studies and my team uses a GitHub repository. I am in charge of creating the GUI and I am stuck at the very beggining.
I want to create the main application window using WPF, but when I use toolbox > choose items, I can not see the WPF tab. Also, when I am trying to enable the designer view, nothing happens.
Is it perhaps the software version being Visual Studio Community 2013 causing the issue? Do I need to have the Visual Studio Professional version in order to use WPF toolbox?
I'm attaching a link to the screen of the situation below.
As I presumed, all I needed was the professional version of Visual Studio. After obtaining and installing it everything works fine.
I just realised that Blend for Visual Studio 2012 does not support WPF apps under W7.
Once I opened a window I can only see raw XAML.
I need to edit a style for a chart dataseries System.Windows.Controls.DataVisualization.Charting. I normally use Blend for these kind of tasks - because it pulls default styles from somewhere and gives it to you in a blink of an eye.
now I am stuck.. what would you guys do?
P.S. here is nice summary for future references: http://blendinsider.com/technical/available-now-blend-for-visual-studio-2012-2012-08-15/
(scroll down to see the table what version supports what)
You need to use the Blend Preview that supports WPF apps.
http://expression.microsoft.com/en-us/jj154135
How can I design an animation with a WPF project in Visual Studio 2012?
Visual Studio 2012 Update 2 will have a released version of Blend which supports WPF...in the meantime use the preview one.
http://www.microsoft.com/expression/