Change default format for DateTime parsing in ASP.NET Core

Question

I get a Date in an ASP.NET Core Controller like this:

public class MyController:Controller{
    public IActionResult Test(DateTime date) {

    }
}

Answer 1

Consider using a custom TypeConverter for your datetime (Source):

using System;
using System.ComponentModel;
using System.Globalization;
using System.Drawing;

public class DeDateTimeConverter : TypeConverter {
   // Overrides the CanConvertFrom method of TypeConverter.
   // The ITypeDescriptorContext interface provides the context for the
   // conversion. Typically, this interface is used at design time to 
   // provide information about the design-time container.
   public override bool CanConvertFrom(ITypeDescriptorContext context, 
      Type sourceType) {

      if (sourceType == typeof(string)) {
         return true;
      }
      return base.CanConvertFrom(context, sourceType);
   }
   // Overrides the ConvertFrom method of TypeConverter.
   public override object ConvertFrom(ITypeDescriptorContext context, 
      CultureInfo culture, object value) {
      if (value is string) {
         if (DateTime.TryParse(((string)value), new CultureInfo("de-DE") /*or use culture*/, DateTimeStyles.None, out DateTime date))
             return date;
      }
      return base.ConvertFrom(context, culture, value);
   }
}

and use TypeConverter attribute on your property:

[TypeConverter(typeof(DeDateTimeConverter))]
public DateTime CustomDateTime { get; set; }

Update

Based on my experience and thanks to this answer and @zdeněk comment, TypeConverter attribute do not work and you should register TypeConverter in Startup.cs:

TypeDescriptor.AddAttributes(typeof(DateTime), new TypeConverterAttribute(typeof(DeDateTimeConverter)));