// Dependencies(Nuget): DNTPersianUtils.Core

  public class PersianDateModelBinder : IModelBinder
    {
        public Task BindModelAsync(ModelBindingContext bindingContext)
        {
            var valueResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);

            DateTime? dt;

            try
            {
                var value = valueResult.FirstValue;


                var isValidPersianDateTime = value != null && DNTPersianUtils.Core.PersianDateTimeUtils.IsValidPersianDateTime(value);

                if (isValidPersianDateTime)
                {
                    dt = DNTPersianUtils.Core.PersianDateTimeUtils.ToGregorianDateTime(value);
                }
                else
                {
                    dt = null;
                }

            }
            catch (Exception e)
            {
                dt = null;
            }

            if (dt == null)
            {
                bindingContext.ModelState.TryAddModelError(bindingContext.ModelName, "Jalali date is not valid");
            }
            else if (Nullable.GetUnderlyingType(bindingContext.ModelType) == typeof(DateTime))
            {
                bindingContext.Result = ModelBindingResult.Success(dt);
            }
            else
            {
                bindingContext.Result = ModelBindingResult.Success(dt.Value);
            }

            return Task.CompletedTask;
        }


        public class PersianDateModelBinderProvider : IModelBinderProvider
        {
            private readonly IModelBinder _binder = new PersianDateModelBinder();

            public IModelBinder GetBinder(ModelBinderProviderContext context)
            {
                var isDateTimeNullableType = context.Metadata.ModelType == typeof(DateTime?);
                var isDateTimeType = context.Metadata.ModelType == typeof(DateTime);

                return isDateTimeType || isDateTimeNullableType ? _binder : null;
            }
        }
    }



How To Use:

In Startup.cs:

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvcCore(options =>
        {
            options.ModelBinderProviders.Insert(0, new PersianDateModelBinderProvider());
        });
    }

In Actions:

     public async Task<IActionResult> SampleAction(DateTime birthDate)
        {
            if (ModelState.IsValid)
            {
                //birthDate is valid
            }
            else
            {
                birthDate is wrong
            }

            ...
        }

//or with nullable datetime:
        public async Task<IActionResult> SampleAction(DateTime? birthDate)
        {
            if (ModelState.IsValid)
            {
                //birthDate is valid
            }
            else
            {
                //birthDate is wrong
            }

            ...
        }