ICoreWebView2UploadStartingEventHandler

[Apivan]

The current webview have
ICoreWebView2DownloadStartingEventHandler.

Theoretically, ICoreWebView2UploadStartingEventHandler should not be required since the webview is in the same computer as user do download. Am i understand this right?

However, we would rather have same consistency of webview deployment and web browser without touching the HTML/JS code.
Otherwise, the upload procedure for webview need to call by different interface Js code.

Does this API already exist in another WebView-like product? (CEF, WebBrowser, etc.)

Yes
virtual CefRefPtr GetDialogHandler() { return nullptr; }
can be used for intercepting before-uploading event. (not to be confused with ClientHandler::OnBeforeDownload)

Details showing the usage/consumption of the proposed new API, and alternatives (e.g. not having this API).

I used ExecuteScript with Blob Base64 string to the Js' DataTransfer object which send to html element.

AB#40880038

[nishitha-burman]

Thanks for the feedback! We've added this as a scenario on our backlog!

[nishitha-burman]

Hi @Apivan, can you please describe the scenarios you are trying to address with this feature?

Thank you

[Apivan]

I need to change the native file browser dialog to something else. I don't want a user to use native dialog because it can delete a file while browsing it. We want simple and restrictive dialog. Our app may deploy in kiosk mode and have very extreme restrictive use.

[nishitha-burman]

Thank you @Apivan for the details. Are you looking to build a dialog using native UI to upload a file?

[Apivan]

Thank you for reply.

Are you looking to build a dialog using native UI to upload a file?

No, that part is already done.

I am looking for a way to integrate that customized native file system UI to webview2 the same way CEF can.
Currently, it go to javascript DataTransfer. it works but got blob size limitation.

[Apivan]

I can give you another scenario.
The html <input type='file'> do not allow to change its value programmatically due to online security. But for webview2 app, this security is get in the way. At the moment, the only way we can change the value of is to .click() and use the native file system dialog.

[nishitha-burman]

Hi @Apivan,

To make sure I understand correctly, are you looking for support for a ICoreWebView2UploadStartingEventHandler so that you can intercept and replace with your own dialog? Also, for the example you provided with the html <input type='file'>, are you looking to programmatically change the value?

Thanks,
Nishitha

[apivan2]

Hi @nishitha-burman

Thank you very much for your response.
Yes, I am looking for the ICoreWebView2UploadStartingEventHandler in order to replace my existing special dialog.

However, if it is possible to implement the functionality of programmatically changing the value of <input type='file'>, then ICoreWebView2UploadStartingEventHandler will not be necessary.

Essentially, the ability to programmatically change the value of <input type='file'> is a superset of ICoreWebView2UploadStartingEventHandler in terms of use cases.

Thanks,
Apivan

[nishitha-burman]

Hi @Apivan,

Can you please explain how programmatically changing the value of <input type='file'> would allow you to replace the existing dialog? Also, what are some types you would like to programmatically change the value to?

Thanks!

[apivan2]

Hi @nishitha-burman

In most cases, the <input type='file'> tag is hidden and a separate button is used to activate the upload functionality for styling reason. If this button was modified to open a custom dialog instead of connecting to the input file, then programmatically changing the value of <input type='file'> could complete the workflow.

However, I aware that allowing this behavior could require significant code refactoring for a minor feature.

Additionally, there are other ways to integrate a custom file upload dialog with the current web view.

Please ignore this request if it is not practical to do so.