description	title	ms.date	keywords
Event args for the `WebMessageReceived` event.	WebView2 Win32 C++ ICoreWebView2WebMessageReceivedEventArgs	02/09/2022	IWebView2, IWebView2WebView, webview2, webview, win32 apps, win32, edge, ICoreWebView2, ICoreWebView2Controller, browser control, edge html, ICoreWebView2WebMessageReceivedEventArgs

interface ICoreWebView2WebMessageReceivedEventArgs

interface ICoreWebView2WebMessageReceivedEventArgs
  : public IUnknown

Event args for the WebMessageReceived event.

Summary

Members	Descriptions
get_Source	The URI of the document that sent this web message.
get_WebMessageAsJson	The message posted from the WebView content to the host converted to a JSON string.
TryGetWebMessageAsString	If the message posted from the WebView content to the host is a string type, this method returns the value of that string.

Product	Introduced
WebView2 Win32	0.9.430
WebView2 Win32 Prerelease	0.9.488

The URI of the document that sent this web message.

public HRESULT get_Source(LPWSTR * source)

The message posted from the WebView content to the host converted to a JSON string.

public HRESULT get_WebMessageAsJson(LPWSTR * webMessageAsJson)

Run this operation to communicate using JavaScript objects.

For example, the following postMessage runs result in the following WebMessageAsJson values.

postMessage({'a': 'b'})      L"{\"a\": \"b\"}"
postMessage(1.2)             L"1.2"
postMessage('example')       L"\"example\""

If the message posted from the WebView content to the host is a string type, this method returns the value of that string.

public HRESULT TryGetWebMessageAsString(LPWSTR * webMessageAsString)

If the message posted is some other kind of JavaScript type this method fails with the following error.

E_INVALIDARG

Run this operation to communicate using simple strings.

For example, the following postMessage runs result in the following WebMessageAsString values.

postMessage({'a': 'b'})      E_INVALIDARG
postMessage(1.2)             E_INVALIDARG
postMessage('example')       L"example"