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BlazorWebView: Uncaught SyntaxError: Identifier 'channel' has already been declared.

See original GitHub issue

Description

Running Maui Hybrid application on Android gives the following error: Uncaught SyntaxError: Identifier 'channel' has already been declared.. On other platforms like Windows it is working fine.

Steps to Reproduce

https://gitlab.com/fairking/napos/-/tree/4-maui-spa

Version with bug

Release Candidate 3 (current)

Last version that worked well

Unknown/Other

Affected platforms

Android

Affected platform versions

Android 9.0

Did you find any workaround?

If I refresh the page the error disappears.

Relevant log output

No response

Issue Analytics

State:
Created a year ago
Comments:11 (4 by maintainers)

Top GitHub Comments

1reaction

fairkingcommented, Jun 12, 2022

You’ll need to move the _framework/blazor.webview.js script to be within the <body> tag and re-add the autostart="false".

Thanks. It fixed the issue. Double checked Windows and Android version in Release mode and everything is working so far.

As a solution I have added the following lines:


export default boot(async ({ app }) => {

    try {
        await (window as any).Blazor.start(); // Throws exception
    } catch { }
    try {
        await (window as any).DotNet.boot(); // Throws exception
    } catch { }

    app.config.globalProperties.$version = version;
    app.config.globalProperties.$settings = await SettingService.get();

});

1reaction

TanayParikhcommented, May 24, 2022

You’ll need to move the _framework/blazor.webview.js script to be within the <body> tag:

https://gitlab.com/fairking/napos/-/blob/4-maui-spa/Napos/wwwroot/index.html#L18

and re-add the autostart="false". See the blazor .net maui template here.

The call window.DotNet.invokeMethodAsync() causes the issue, not the app ☹️

Which call are you referring to? Is it the framework making the call, or user code?

But this is Blazor issue.

If you believe this to be an issue in the framework, please provide a minimal (with all code not related to the issue removed), public github repository that reproduces this issue. The current repro is large and has a bunch of application specific code, so it’s hard to look into this issue without having context on the repo and it’s architecture.