Blazor WASM input time fails to show values after upgrade to .NET 5

This issue has been moved from a ticket on Developer Community.

---

[severity:It’s more difficult to complete my work] [regression] [worked-in:3.1] I have a Blazor WASM project that I just have upgraded to .NET 5. After upgrade my input time:

@code{
    DateTime myTime = DateTime.Now.ToLocalTime();
    string myTimeFormat = "HH:mm:ss"; 
}

only shows “–:–” instead of the time on the format “HH:mm:ss” that it used to do.

Chrome (and Edge) console prints.

blazor.webassembly.js:1 The specified value “12.52.58” does not conform to the required format. The format is “HH:mm”, “HH:mm:ss” or “HH:mm:ss.SSS” where HH is 00-23, mm is 00-59, ss is 00-59, and SSS is 000-999.

I posted this as question on SO

---

Original Comments

Feedback Bot on 2/19/2021, 07:18 PM:

We have directed your feedback to the appropriate engineering team for further evaluation. The team will review the feedback and notify you about the next steps.

---

Original Solutions

(no solutions)

[Andrzej-W]

In my opinion Blazor WASM works correctly (binding to input type="time") and this issue can be closed.

Unfortunately there are some differences in culture definitions in various environments (Windows 10, Windows Server, Linux, WASM). What is the moral of the story? Whenever you exchange data between different systems, you must use culture-independent date, time, and number formatting, even if you are sure that both systems are set to the same culture.

[Andrzej-W]

@erikthysell run this code to understand the difference between culture dependent and culture independent formatting.

@page "/"
@using System.Threading
@using System.Globalization

<h1>Date and time formatting</h1>

<button class="btn btn-primary" @onclick=@UpdateTime1>Update time en-US</button>
<button class="btn btn-primary m-2" @onclick=@UpdateTime2>Update time da-DK</button>
<input type="time" @bind="myTime" @bind:format=@myTimeFormat />

<div class="alert alert-primary mt-2">Culture dependent formatting: @myTime.ToString(Format1)</div>
<div class="alert alert-primary">Culture independent formatting: @myTime.ToString(Format2)</div>

@code
{
  // Please note that / (slash) will be replaced by culture dependent date separator
  // and : (colon) will be replaced by culture dependent time separator.
  // Letter T is not reserved character and will be included in the output string unchanged
  // (you don't have to use apostrophes around capital letter T)
  // Read section "Date and time separator specifiers" and "Character literals" here:
  // https://docs.microsoft.com/en-us/dotnet/standard/base-types/custom-date-and-time-format-strings#date-and-time-separator-specifiers

  private const string Format1 = "yyyy/MM/ddTHH:mm:ssK";      // string with culture dependent placeholders
  private const string Format2 = "yyyy-MM-ddTHH':'mm':'ssK";  // string with literals - you have to use ' (apostrophe) around colon
  DateTime myTime = DateTime.Now;
  string myTimeFormat = "HH':'mm':'ss";  // use apostrophes around colons, otherwise colon will be replaced by culture dependent time separator

  private void UpdateTime1()
  {
    Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");
    myTime = DateTime.Now;
  }
  private void UpdateTime2()
  {
    Thread.CurrentThread.CurrentCulture = new CultureInfo("da-DK");
    myTime = DateTime.Now;
  }
}