NavigateToString with a very large string shows error "Value does not fall within the expected range"

[smohanty05]

Hi,
I am using WPF Webview2 control. I saw with some specific large data NavigateToString method throws below error:
System.ArgumentException
HResult=0x80070057
Message=Value does not fall within the expected range.
Source=Microsoft.Web.WebView2.Core
StackTrace:
at Microsoft.Web.WebView2.Core.Raw.ICoreWebView2.NavigateToString(String htmlContent)
at Microsoft.Web.WebView2.Core.CoreWebView2.NavigateToString(String htmlContent)
at WebView2Sample.MainWindow.<Window_Loaded>d__1.MoveNext()

Note: The issue is not seen using Navigate method or setting Source property.

Is this a known issue? NavigateToString has any limitations?

AB#33629225

[champnic]

There probably is some limitation to the size of string that can be navigated. I've opened this as a doc bug to figure out what that limit is and update our documentation. Thanks!

[smohanty05]

Thanks for confirming this is a known issue!!

[ShaunLoganOracle]

In the version of the SDK I use (1.0.705.50), for WinForms, I see CoreWebView2.NavigateToString has a 2MB limit specified in the doc for that method.

      //
      // Summary:
      //     Initiates a navigation to htmlContent as source HTML of a new document.
      //
      // Parameters:
      //   htmlContent:
      //     A source HTML of a new document.
      //
      // Remarks:
      //     The htmlContent parameter may not be larger than 2 MB in total size. The origin
      //     of the new page is about:blank.
      public void NavigateToString (string htmlContent);

[champnic]

Nice find @ShaunLoganOracle! It looks like we have that remark in the CoreWebView2 version of the function, but not in the WPF or WinForms WebView2 versions.
https://docs.microsoft.com/en-us/dotnet/api/microsoft.web.webview2.core.corewebview2.navigatetostring?view=webview2-dotnet-1.0.864.35#remarks

[clovett]

Why the limit at all? This is very annoying. I did not have this limit on the old System.Windows.Forms.WebBrowser component ?!

[champnic]

We've updated the docs to be consistent, thanks!

[champnic]

@clovett I believe the issue is the cross-process call from the host app to the WebView2 processes. The WebBrowser didn't have this limitation because it was all in-proc.

[lovettchris]

I really don't care about your implementation details, you should find a solution. Pushing weird limitations like this off on the customer is why people complain about windows API's all the time. Couldn't you wrap the call in your WinForms, Wpf libraries and solve this some hidden way so it is not exposed to the customer like this?

[champnic]

Sure I can reopen the bug to take a look at the underlying limitation. Thanks!

[burleyman24]

The 2MB limitation prevents any real ability to include inline images in the the NavigateToString method. This is a key functionality that existed previously in the WebBrowser component and would be a key ability for us to migrate to WebView2. Here is our up vote to find a solution to this limitation.

[DavidBerg-MSFT]

Same here. I just ported my app to WebView2. It passed my basic tests, then I went to demo and got this crash. I checked, the string I was trying to navigate to was 4MB. Fortunately I put in a switch, so I can just change the default and revert, but it's annoying. I'm mostly still using the old (IE based) WebBrowser because both WebView and WebView2 have blocking bugs (also, my WebView2 code is more complex since I have to initialize the component and then wait for it before I can do anything else).

Is there any other way to pass a large string? (I suppose I could write it to a temp file, then navigate to the file, but then I have to remember to clean up the temp file).

How hard would it be for the NavigateToString method to chunk the string up and pass it across process in parts? (Or create an appropriate sized shared memory region?)