@page "/" <h1>Example Datetime in Blazor</h1> <h2>Last date of Month</h2> <div class="wrapper"> <form> <div class="form-group"> <label>Date </label> <input id="txtDate" type="date" required @bind-value="_precio.Fecha_Inicio" /> </div> <div class="form-group"> <label>Date (last date of Month)</label> <input id="txtDate" type="date" required @bind-value="_precio.Fecha_Final" /> </div> </form> </div> @code{ private Precio _precio; protected override void OnInitialized() { _precio = new Precio(); _precio.Fecha_Inicio = DateTime.Today; } public class Precio { private DateTime _fechaInicio; public DateTime Fecha_Inicio { get { return _fechaInicio; } set { _fechaInicio = value; Fecha_Final = new DateTime(value.Year, value.Month, 1).AddMonths(1).AddDays(-1); } } public DateTime Fecha_Final { get; set; } } }
namespace BlazorFiddleProject { using Microsoft.AspNetCore.Components.Builder; using Microsoft.Extensions.DependencyInjection; public class Startup { public void ConfigureServices(IServiceCollection services) { } public void Configure(IComponentsApplicationBuilder app) { app.AddComponent<App>("app"); } } }
<!DOCTYPE html> <html> <head> <meta charset="utf-8"/> <meta name="viewport" content="width=device-width"> <title>BlazorFiddleProject</title> <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous"> <script src="_content/MatBlazor/dist/matBlazor.js"></script> <style> app { } </style> <script type="text/javascript"> </script> </head> <body> <app>Loading...</app> <script src="_framework/blazor.webassembly.js"></script> <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script> <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script> </body> </html>

Add component

BlazorFiddle was updated from Blazor 0.7 to .NET Core 3.0. Your old source code could not work. You need to upgrade to latest.