Known Issues of the WebView control for Windows Forms and WPF applications

This document describes issues and limitations in this release of the WebView control.

Answers to a number of Frequently Asked Questions on WebView for Windows Forms and WPF applications are also available.

WebView control members

The WebView control does not implement these methods of the IWebViewControl.

The WebView control implements these events of the IWebViewControl, but they don't work as expected.


  • Contrary to its name, the WebViewControl.InvokeScriptAsync method is not actually asynchrounous, as the Win32 application and WebView share the same input queue.

  • WebViewControl.InvokeScriptAsync only returns strings. For example, WebView.InvokeScriptAsync("eval", "1==1") returns an empty string rather than true, unless you use toString: WebView.InvokeScriptAsync("eval", "(1==1).toString()")

Rendering and layout


  • WebView controls in WPF applications have longer load times than Windows Forms applications.

  • If the web view stops responding or stops working, other applications that use the same underlying process (WWAHost) will stop responding or stop working as well.


  • WebView controls don't render in XAML Browser Applications (XBAP).

    That's because a browser has partial trust to the system while WebView controls have full-trust.

  • Content in the WebView can be blocked even if the user responds to a system prompt by providing permission to the control.

    This can happen if the Win32WebViewHost (or "Desktop Web App Viewer" in Insider builds) application is disabled in the location settings of the user's system. To resolve the issue, users can open those settings and enable the Win32WebViewHost (or "Desktop Web App Viewer" in Insider builds) application.

  • WebView controls won't function as expected in a WPF-based ClickOnce application.

  • WebView controls function only in applications that use a Single-Threaded Apartment (STA) model. Multithreaded Apartment (MTA) model is not supported.

  • WebView controls have not been tested for Windows Information Protection. Therefore, the information that moves in and out of the WebView control might not be properly secured even if an organizational administrator applies a Windows Information Protection policy to the hosting application.

  • WebView controls have not been exhaustively tested for security.

User interaction

  • Accelerator keys don't work in WebView controls.

  • Users can't use the TAB key to put the WebView into focus. They'll have to use the mouse or other pointing device to put the WebView control into focus.

Paths and strings

  • You can use only absolute URIs to resources in members of the WebView control that accept string paths.

  • WebView controls don't recognize the ms-appx:/// prefix, so they can't read from the package (if you've created a package for your application).

  • WebView controls don't recognize the File:// prefix. If you want to read a file into a WebView control, call the NavigateToLocal(String) or the NavigateToLocalStreamUri(Uri, IUriToStreamResolver) method, or add code to your application that reads the content of the file. Then, serialize that content into a string, and call the NavigateToString(String) method of the WebView control.

  • WebView controls don't support URI's that are not encoded in UTF-8. Characters between UTF-16 and UTF-32 aren't supported.

  • WebView controls don't support URIs that are greater than 2048 characters.

Host container

  • WebView controls can be hosted in a popup window. We recommend that you do not do this because support for that scenario will soon be disabled for security reasons.

  • Web applications that run in a WebView control can't initiate downloads.

  • Service workers can't run in a WebView control.

WebView browser

  • The WebBrower.ObjectForScripting property and WebView.AddWebAllowedObject(String, Object) are not supported.

    Instead, use the WebViewControl.InvokeScriptAsync method.

  • You can't programmatically navigate by using a new window.

  • You can't programmatically navigate to a specific frame.

  • You can't programmatically print information from a WebView control.

  • There's no way to programmatically refresh content with cache validation. By default, pages refresh without cache validation by sending a "Pragma:no-cache" header to the server.