Getting a JSInterop Exception when using this extension:

[Microsoft.AspNetCore.Components.WebAssembly.Rendering.WebAssemblyRenderer] Exception: Microsoft.JSInterop.JSException: Could not find 'WebUSB' in 'window.BlazorExtensions'.
Error: Could not find 'WebUSB' in 'window.BlazorExtensions'.

Followed instructions and checked test implementation in source code, cannot find anything different in my code.

Thanks.

This package is basically send/receive calls using byte[] which is translated on the JS side to Uint8Array.

Currently Blazor fail to deserialize Uint8Array to byte[] on the C# side. We are tracking an issue on Blazor repo here https://github.com/aspnet/Blazor/issues/1618 and as soon as it get fixed, we should update this component since the current implementation is not efficient.

For now we are translating the response buffer to a regular array by using this hack: https://github.com/BlazorExtensions/WebUSB/blob/master/src/Blazor.Extensions.WebUSB.JS/src/USBManager.ts#L181

Do you have example for NET 8 Blazor client?

I just installed the webusb extension in my first blazor project. Unfortunately it gives me this error on the console.

Similar errors in the issuelists of other blazor extensions lead me to believe that this is caused by newer versions of blazor breaking something related to static content. But nothing I found suggested worked for me.

As to recreate, I just started a new blazor app from the vs template and added the extension. I also added the code from this project its testpage.

blazor.webassembly.js:1 crit: Microsoft.AspNetCore.Components.WebAssembly.Rendering.WebAssemblyRenderer[100]
Unhandled exception rendering component: Could not find 'BlazorExtensions' in 'window'.
Error: Could not find 'BlazorExtensions' in 'window'.
at https://localhost:44355/_framework/blazor.webassembly.js:1:9130
at Array.forEach ()
at p (https://localhost:44355/_framework/blazor.webassembly.js:1:9090)
at https://localhost:44355/_framework/blazor.webassembly.js:1:9800
at new Promise ()
at Object.beginInvokeJSFromDotNet (https://localhost:44355/_framework/blazor.webassembly.js:1:9773)
at _mono_wasm_invoke_js_marshalled (https://localhost:44355/_framework/wasm/dotnet.3.2.0.js:1:171294)
at do_icall (https://localhost:44355/_framework/wasm/dotnet.wasm:wasm-function[6049]:0x10f8b1)
at do_icall_wrapper (https://localhost:44355/_framework/wasm/dotnet.wasm:wasm-function[1896]:0x50b6a)
at interp_exec_method (https://localhost:44355/_framework/wasm/dotnet.wasm:wasm-function[1120]:0x2588e)
Microsoft.JSInterop.JSException: Could not find 'BlazorExtensions' in 'window'.
Error: Could not find 'BlazorExtensions' in 'window'.
at https://localhost:44355/_framework/blazor.webassembly.js:1:9130
at Array.forEach ()
at p (https://localhost:44355/_framework/blazor.webassembly.js:1:9090)
at https://localhost:44355/_framework/blazor.webassembly.js:1:9800
at new Promise ()
at Object.beginInvokeJSFromDotNet (https://localhost:44355/_framework/blazor.webassembly.js:1:9773)
at _mono_wasm_invoke_js_marshalled (https://localhost:44355/_framework/wasm/dotnet.3.2.0.js:1:171294)
at do_icall (https://localhost:44355/_framework/wasm/dotnet.wasm:wasm-function[6049]:0x10f8b1)
at do_icall_wrapper (https://localhost:44355/_framework/wasm/dotnet.wasm:wasm-function[1896]:0x50b6a)
at interp_exec_method (https://localhost:44355/_framework/wasm/dotnet.wasm:wasm-function[1120]:0x2588e)
at System.Threading.Tasks.ValueTask`1[TResult].get_Result () <0x2df6dd0 + 0x00034> in :0
at Blazor.Extensions.WebUSB.USB.Initialize () [0x00041] in /home/runner/work/WebUSB/WebUSB/src/Blazor.Extensions.WebUSB/USB.cs:78
at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask (System.Threading.Tasks.Task taskToHandle) <0x2db6878 + 0x000b6> in :0

Hi,
I use Blazor wasm project and after I choose device in Chrome, I get:

My call:

var requestedDevices = await _usb.RequestDevice(); bool opened = requestedDevices.Opened; Console.WriteLine("Conbox opened state: " + opened); await requestedDevices.Open();

Response:
blazor.webassembly.js:1 crit: Microsoft.AspNetCore.Components.WebAssembly.Rendering.WebAssemblyRenderer[100] Unhandled exception rendering component: Access denied. undefined Microsoft.JSInterop.JSException: Access denied. undefined at System.Threading.Tasks.ValueTask1[TResult].get_Result () <0x306d990 + 0x00034> in :0
at Blazor.Extensions.WebUSB.USBDeviceMethods.Open (Blazor.Extensions.WebUSB.USBDevice device) [0x0003c] in /home/runner/work/WebUSB/WebUSB/src/Blazor.Extensions.WebUSB/USBDevice.Methods.cs:25 `

Regardless of the user being listening or not to Connect/Disconnect events, this component should list to it from the navigator.usb connect/disconnect events.

Right now, it requires a call to a hack method IUSB.Initialize() and connect is never fired for whatever reason while disconnect sometimes is fired.

We should fix it...

Hi,

Really stoked to find this library. Let's collaborate. This is my framework. I'd like to write an implementation for it using your library.

https://github.com/MelbourneDeveloper/Device.Net

I'm currently trying to get your library working.

Code:

@page "/counter"
@inject IUSB usb

<h1>Counter</h1>

<p>Current count: @currentCount</p>

<button class="btn btn-primary" @onclick="IncrementCount">Click me</button>

@code {

    [Inject] private IUSB _usb { get; set; }

    private int currentCount = 0;

    private async Task IncrementCount()
    {
        await _usb.Initialize();
        var devices = await _usb.GetDevices();
        currentCount = devices.Count();
    }
}

But I get this error:

Any ideas?

Christian

When trying to start the application after installing WebUSB, the app crashes with the following message:
An error occurred while starting the application.
AggregateException: Some services are not able to be constructed (Error while validating the service descriptor 'ServiceType: Blazor.Extensions.WebUSB.IUSB Lifetime: Singleton ImplementationType: Blazor.Extensions.WebUSB.USB': Cannot consume scoped service 'Microsoft.JSInterop.IJSRuntime' from singleton 'Blazor.Extensions.WebUSB.IUSB'.)
Microsoft.Extensions.DependencyInjection.ServiceProvider..ctor(IEnumerable serviceDescriptors, ServiceProviderOptions options)

InvalidOperationException: Error while validating the service descriptor 'ServiceType: Blazor.Extensions.WebUSB.IUSB Lifetime: Singleton ImplementationType: Blazor.Extensions.WebUSB.USB': Cannot consume scoped service 'Microsoft.JSInterop.IJSRuntime' from singleton 'Blazor.Extensions.WebUSB.IUSB'.