Microsoft Edge WebView2 - Sample crashes on Load

Question

I took the latest version of Microsoft.Web.WebView2 (0.9.515-prerelease) and added to a test C# WinForms application. Am using VS 2019, .NET framework is 4.7.2. Placed the WebView2 control on a form, compiled and ran. The application crashed on Load, at the below point in Form1.designer.cs.

    // webView21
    // 
    this.webView21.Location = new System.Drawing.Point(153, 66);
    this.webView21.Name = "webView21";
    this.webView21.Size = new System.Drawing.Size(492, 253);
    this.webView21.Source = new System.Uri("about:blank", System.UriKind.Absolute);
    this.webView21.TabIndex = 0;
    this.webView21.Text = "webView21";
    this.webView21.ZoomFactor = 1D;
    // 
    // Form1
    // 
    this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
    this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
    this.ClientSize = new System.Drawing.Size(800, 450);
    this.Controls.Add(this.webView21); //CRASHED HERE WITH BELOW EXCEPTION -

When I run this in Release mode, get the following exception trace - System.NullReferenceException: Object reference not set to an instance of an object.

   at Microsoft.Web.WebView2.WinForms.WebView2.OnVisibleChanged(EventArgs e)
   at System.Windows.Forms.Control.OnParentVisibleChanged(EventArgs e)
   at System.Windows.Forms.Control.OnVisibleChanged(EventArgs e)
   at System.Windows.Forms.ScrollableControl.OnVisibleChanged(EventArgs e)
   at System.Windows.Forms.Form.OnVisibleChanged(EventArgs e)
   at System.Windows.Forms.Control.WmShowWindow(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.Form.WmShowWindow(Message& m)
   at System.Windows.Forms.Form.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

If I take the latest stable version of WebView2 (v 0.9.488), it throws a compilation error as it does not reflect Microsoft.Web

Please let me know how to fix this error. Appreciate your help very much. Came across this question 8 months ago but am hoping Microsoft has gone beyond that now. How can I use the Microsoft Edge WebView2 control in C# windows application

The Sample solution Microsoft created does have C# version as well for WinForms. https://github.com/MicrosoftEdge/WebView2Samples

Tried this sample given by Microsoft as well. It too crashes. https://learn.microsoft.com/en-us/microsoft-edge/webview2/gettingstarted/winforms

Are you having right version of Microsoft Edge installed for WebView2? e.g WebView2 0.9.515-prerelease requires minimum of Microsoft Edge 84.0.515.0 installed? https://learn.microsoft.com/en-us/microsoft-edge/webview2/releasenotes — Erkki Nokso-Koivisto, May 19 '20 at 15:03
The sample app says "Ensure a complete URL is entered in the address bar. An ArgumentException is thrown if the URL does not start with http:// or https://", and your app is trying to load "about:blank". Maybe that is the problem? — GreatBigGiantBrain, May 19 '20 at 21:06
It does not even get to the load event. The exception is in the designer code itself, while the designer code adds the control to form. — Krishnan V S, May 20 '20 at 19:17
Not sure if I am missing something very basic - I checked the version of MS Edge in laptop, it says this "Microsoft Edge is up to date. Version 81.0.416.77 (Official build) (64-bit)". But why is 84.0.* stated as the min version in that weblink ? — Krishnan V S, May 20 '20 at 19:21

score 6 · Answer 1 · answered May 20 '20 at 04:18

6

you need to make sure 1) the Edge version is right. try download Canary version Edge from Url https://c2rsetup.officeapps.live.com/c2r/downloadEdge.aspx?ProductreleaseID=Edge&platform=Default&version=Edge&source=EdgeInsiderPage&Channel=Canary&language=en

and 2) set x86 as the target platform will fix the problem.

answered May 20 '20 at 04:18

PaulYBChiang

61
1

Edge version is Version 81.0.416.77 (Official build) (64-bit). I tried setting to x86 version as target now but still get the same exception. – Krishnan V S May 20 '20 at 19:16
1

@Krishnan V S, you need Edge Canary to get it work. – PaulYBChiang May 21 '20 at 02:46
Oh is it? Thank you, will try that. – Krishnan V S May 22 '20 at 06:50
I had the same problem, even though I had stable edge on my PC, I still had to install the canary version alongside it. After I did that, everything worked. – shawty Jun 03 '20 at 13:43
Your solution helped me, I was having the same problem. – evry1falls Jul 20 '21 at 18:39

score 3 · Answer 2 · answered Jul 11 '20 at 01:06

I faced the same issue but I was able to solve it. It crashes any time the traget CPU is "Any CPU" but if you change it to either "x86" or "x64", it runs successfully in my case. Seems it is not able to check and work with unspecified target CPU architecture.

I hope this saves someone lots of headaches

Carlos Sánchez López · Answer 3 · 2020-09-06T21:01:35.333

Unfortunately, this is still an issue in 0.9.515-prerelease. There's a bug opened against this and I added some more details about my repro:

https://github.com/MicrosoftEdge/WebViewFeedback/issues/228#issuecomment-687873636

Edit: The x86 suggestion does not apply for you if you install Edge for x64 bits. You can build it for x64 and it will work. More details in my response in the issue: https://github.com/MicrosoftEdge/WebViewFeedback/issues/228#issuecomment-687900181

score 1 · Answer 4 · answered Sep 27 '20 at 16:53

Following the set platform guidance...

If you are using Canary Microsoft.Web.WebView2.0.9.628-prerelease. There is a known issue, the current solution is to downgrade to Microsoft.Web.WebView2.0.9.579-prerelease.

https://github.com/MicrosoftEdge/WebView2Feedback/issues/431

This worked for me.

score 0 · Answer 5 · answered May 20 '20 at 03:12

from the path of my Edge, "C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe", we may conclude the current Edge is 32bit program? wat about give a try setting platform target to x86. some guru said, with x86 set, it will work!

from the MS sample project WebView2WindowsFormsBrowser.csproj, the Microsoft.Web.WebView2 version should be "0.9.515-prerelease".

score 0 · Answer 6 · answered Jul 11 '20 at 21:48

As stated by others, the minimum Microsoft Edge version is 84.0.515.0 when using WebView2 0.9.515-prerelease. You can download the required Microsoft Edge version from the Microsoft Edge Insider Channel. See the link below.

Here are some useful links when using WebView2:

Microsoft Edge Insider Channels: https://www.microsoftedgeinsider.com/en-us/download
WebView2 Release Notes: https://learn.microsoft.com/en-us/microsoft-edge/webview2/releasenotes
WebView2 Bug Reporting/Feedback (click on "Issues"): https://github.com/MicrosoftEdge/WebViewFeedback

score 0 · Answer 7 · answered Sep 09 '20 at 12:23

The WebView2 component may generate an exception and crash the application during loading if it does not have permission to create the data folder needed to store user settings, etc.

If the application loads correctly when launched from Visual Studio or from other unrestricted locations, but fails to load when installed into Program Files, then this is a possible issue.

By default, the data folder is created in the same folder as the application exe, which can fail in Program Files. The data folders needs to be set to an alternative location.

This link provides some info on the use of data folders: Managing the User Data Folder

This issue provides some code for setting the data folder for WebView2 to a valid location: WebView2 C# Winforms application doesn't work when installed in Program Files folder #297

score 0 · Answer 8 · answered Feb 28 '22 at 22:40

0

This worked for me:

 var userDataFolder = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData) + "\\OurSoftware";
var env = await CoreWebView2Environment.CreateAsync(null, userDataFolder);

answered Feb 28 '22 at 22:40

Skyfish

119
2
4

score 0 · Answer 9 · answered Oct 12 '22 at 05:27

I encounter this problem today. My app works flawlessly until today. Turned out Edge Canary has automatically updated, and my WebView2 library (ver. 1.0.11xx) in app become deprecated. I use Nuget Package Manager. So I open Nuget Package Manager menu, Package Manager Console. Type in

Update-Package

After update, my WebView2 library updated to 1.0.13xx version. My app continues to work again.

Microsoft Edge WebView2 - Sample crashes on Load

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