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c#microsoft-edgecefsharpwebview2embedded-browser

WebView2: Multiple instances of same application need to launch the same browser control

Problem

I recently replaced a System.Windows.Forms.WebBrowser-based control with one that relies on Microsoft.Web.WebView2.WinForms.WebView2 instead. This has been working well, except that my users want to have 2 instances of their application running at once, with both instances occasionally having that WebView2 form open at the same time. When they try this, one of the two instances fails to load the WebView2 control until the other one is closed.

Learned / attempted so far:

I've found WebView2 to be extremely finicky, so I've looked into alternatives like CefSharp, but haven't wanted to dedicate time to implementing them until I know they can solve the problem. So far as I can tell, CefSharp and WebView2 do very similar things as far as launching a Chromium-based browser, rendering to a WinForms control.

This blog post (read: advertisement) for paid alternative DotNetBrowser indicates that

You can initialize and use several Chromium engines simultaneously with different configurations [in DotNetBrowser], which is not possible in CefSharp.

I'm wondering if this same limitation applies to WebView2, and is the cause of my users' inability to have 2 instances of that same form loaded at once.

Context

I'm supporting an ancient desktop CRM that's set to be retired in favor of a modern alternative, but in the mean time, the old standard needs to integrate with new processes we're bringing in. One of those new processes is a web page from an external service that our call center users enter data into, then expect the CRM to pull entered data out of the web page.

The part of their process I did not know about is the 2-instance bit from above: they're used to being able to copy-and-paste from one embedded browser window to the other.

Solution

  • @Poul Bak in the comment on the question had it right: providing settings that differ per-instance of the application fixed the problem.

    The setting I changed per-instance was the path of the user data folder: I was able to pass different values for the userDataFolder argument of the CoreWebView2Environment.CreateAsync method, branching based on a variable that holds different values between the instances that my users are running.