这可能是因为reconnectDialog.js组件没有正确引入造成的。可以在Program.cs文件中添加以下代码来确保reconnectDialog.js通过Blazor WebAssembly启动时正确引入：

builder.Services.AddHttpClient("MyBlazorApp.ServerAPI", client => client.BaseAddress = new Uri(builder.HostEnvironment.BaseAddress)).AddHttpMessageHandler();
builder.Services.AddScoped(sp => sp.GetRequiredService().CreateClient("MyBlazorApp.ServerAPI"));
builder.Services.AddApiAuthorization();
builder.Services.AddTransient();
builder.Services.AddTransient(sp =>
{
    var httpClient = sp.GetService();
    var navigationManager = sp.GetService();
    return new LimitedRetryHttpClientWrapper(httpClient)
    {
        NavigationManager = navigationManager,
        MaxRetries = 1,
        RetryableHttpStatusCodes = HttpStatusCode.RequestTimeout,
    };
});

// Add reconnect logic when the connection is closed
builder.Services.AddTransient();
builder.Services.AddScoped();
builder.Services.AddScoped(sp =>
{
    return new HubConnectionBuilder()
        .WithUrl(navigationManager.ToAbsoluteUri("/streamHub"))
        .AddMessagePackProtocol()
        .Build();
});

在此例中，导入了reconnectDialog.js，并将其注入了服务中以使用。