FileUpload JavaScript Call Exception

[yangf85]

Hi everyone.
I used a method to convert the uploaded file into a stream file.
It worked fine the first time, but an exception occurred the second time. What is the reason for this?
Here is the method, and this is the exception message.

Microsoft.JSInterop.JSException:“Cannot read properties of null (reading '_blazorFilesById') TypeError: Cannot read properties of null (reading '_blazorFilesById') at ut (https://localhost:7266/_framework/blazor.web.js:1:38824) at Object.readFileData (https://localhost:7266/_framework/blazor.web.js:1:38782) at https://localhost:7266/_framework/blazor.web.js:1:3244 at new Promise (<anonymous>) at y.beginInvokeJSFromDotNet (https://localhost:7266/_framework/blazor.web.js:1:3201) at gn._invokeClientMethod (https://localhost:7266/_framework/blazor.web.js:1:62841) at gn._processIncomingData (https://localhost:7266/_framework/blazor.web.js:1:60316) at connection.onreceive (https://localhost:7266/_framework/blazor.web.js:1:53957) at i.onmessage (https://localhost:7266/_framework/blazor.web.js:1:82102)”

[ScarletKuro]

Hi.
Can you post a reproduction project or trymudblazor?
Do you maybe hide the MudFileUpload after upload??

[yangf85]

Sorry, this project has many dependencies, and uploading is quite troublesome.
I did indeed use this MudFileUpload inside a popup, and the popup was hidden after the upload was completed.
When I placed MudUpload on the main page, it worked normally
Is there any way to solve this problem?
But why is it that this component was able to work normally the first time?

[ScarletKuro]

I wasn't asking for the whole project, just minimal reproduction. But since you found the root problem there is no need to.
It's a know limitation of InputFile (MudFileUpload is using it internally). Since you have it in popover when it's closed the DOM that contains the file upload is gone and you get this exception.
I cannot answer why it's working for first time, our MudFileUpload is just a wrapper for Microsoft's InputFile and if you replace with it you will get same problem, you can create an issue in the aspnetcore repository.

[yangf85]

Alright, I will modify the page to keep this upload component always visible, thank you.