Why is my Blazor Server page empty after publishing to IIS?

Question

I'm developing a Blazor Server app that exposes Windows Task Scheduler tasks for remote control with limited controls (I know I can remote to the server's Task Scheduler but this is a request to make it available to some other users inside my organization via local website). The library to access Windows Task Scheduler is Microsoft.Win32.TaskScheduler from NuGet. The app is pretty simple with only 1 component, user is authenticated with Windows Authentication, the app is hosted on an application server's IIS. I'm also new to Blazor and I'm learning by doing it.

Razor page

@page "/"

<h3>Task Manager</h3>

<div>
    @if (TaskList == null)
    {
        <div class="spinner"></div>
    }
    else
    {
        @foreach (var task in TaskList)
        {
            <p>
                @task.Name -
                @task.State -
                @task.Enabled
            </p>
            <p>
                @task.LastRunTime -
                @task.NextRunTime -
                @task.LastTaskResult
            </p>
            <p>
                <input id="btnPause" type="button" disabled="@(task.Enabled ? false : true)" value="Pause" @onclick="() => DisableTask(task)" />
                <input id="btnResume" type="button" disabled="@(task.Enabled ? true : false)" value="Resume" @onclick="() => EnableTask(task)" />
                <input id="btnRun" type="button" disabled="@(task.Enabled ? false : true)" value="Run now" @onclick="() => RunTask(task)" />
                <input id="btnStop" type="button" disabled="@(task.Enabled ? false : true)" value="Stop" @onclick="() => EndTask(task)" />
            </p>
            <br />
        }
    }
</div>

Code behind

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Win32.TaskScheduler;
using Microsoft.AspNetCore.Components;

namespace TaskSchedulerManager.Pages
{
    public partial class TaskManager: ComponentBase
    {
        public IEnumerable<Task> TaskList { get; set; }

        protected override System.Threading.Tasks.Task OnInitializedAsync()
        {
            LoadScheduleTask();
            return base.OnInitializedAsync();
        }

        private void LoadScheduleTask()
        {
            using (TaskService ts = new TaskService())
            {
                TaskFolder root = ts.RootFolder;
                TaskFolder sub = root.SubFolders["Task Scheduler Folder Name"];
                List<Task> tsList = new List<Task>();
                foreach (Task task in sub.Tasks)
                {
                    tsList.Add(task);
                }
                TaskList = new List<Task>(tsList);
            }
        }

        private void DisableTask(Task task)
        {
            task.Enabled = false;
            InvokeAsync(() =>
            {
                StateHasChanged();
            });
        }

        private void EnableTask(Task task)
        {
            task.Enabled = true;
            InvokeAsync(() =>
            {
                StateHasChanged();
            });
        }

        private void RunTask(Task task)
        {
            task.Run();
            InvokeAsync(() =>
            {
                StateHasChanged();
            });
        }

        private void EndTask(Task task)
        {
            task.Stop();
            InvokeAsync(() =>
            {
                StateHasChanged();
            });
        }
    }
}

When I run it locally, all the tasks are displayed on the page as intended. When I publish the app to IIS, the page only shows the header Task Manager , below that it's empty, on the same machine or from local machine. What did I miss?

Answer 1

Webpage was just an empty page because the order of rendering was incorrect.

protected override System.Threading.Tasks.Task OnInitializedAsync()
{
    LoadScheduleTask();
    return base.OnInitializedAsync();
}

change to

return base.OnInitializedAsync();
LoadScheduleTask();
// terminal task...

or something another, always remember order of HTML rendering. Blazor's nature is render HTML by WebAssembly code.