将Xamarin表单中的DateTime格式化为设备格式字符串

问题描述：

在运行PCL Xamarin.Forms项目时，如何将DateTime对象格式化为设备默认日期时间格式的字符串，我的部署目标包括iOS，Android和Windows.

How can I format a DateTimeobject to a string in the device default datetime format when running a PCL Xamarin.Forms project and my deployement targets include iOS, Android and Windows.

根据此线程和此 bug .

是否有任何基于Forms的解决方案，或者我需要从特定于平台的项目中获取它?

Is there any Forms based solution or do I need to get it from platform specific projects?

对于Android，我可以使用DI在Native项目中执行以下操作:

For Android, I can do the following from Native project using DI:

String format = Settings.System.GetString(this.context.ContentResolver 
                                         , Settings.System.DateFormat);
string shortDateString = dateTime.ToString(format);

或者我也可以使用此代码(以下代码的C#版本):

OR I can use this too (the C# version of the below code):

DateFormat dateFormat = android.text.format.DateFormat.getDateFormat(context);

查看此 SO问题以便理解要求更明确(仅适用于android，我希望适用于所有平台，因为这是Xamarin.Forms问题).

Look into this SO question to understand the requirement more clearly (its only for android, I want it for all platforms as this is a Xamarin.Forms question).

由于Xamarin表单中的DatePicker和TimePicker以设备格式显示日期和时间，因此我希望有一种方法可以在PCL中获取它.

Since the DatePicker and TimePicker in Xamarin Forms show the date and time in device format I am hoping there would a way to get it in the PCL.

PCL中还有一个Device类，其中包含诸如平台，成语等信息.

Also there is a Device class in PCL which has information like platforms, idiom, etc.

答

由于找不到任何PCL实现，因此我使用DI来实现要求.

As I could not find any PCL implementation I used DI to implement the requirement.

在PCL中的用法:

DependencyService.Get<IDeviceInfoService>()?.ConvertToDeviceTimeFormat(DateTime.Now);    
DependencyService.Get<IDeviceInfoService>()?.ConvertToDeviceTimeFormat(DateTime.Now);

PCL:

public interface IDeviceInfoService
{
    string ConvertToDeviceShortDateFormat(DateTime inputDateTime);    
    string ConvertToDeviceTimeFormat(DateTime inputDateTime);
}

Android:

[assembly: Dependency(typeof(DeviceInfoServiceImplementation))]
namespace Droid.Services
{
    public class DeviceInfoServiceImplementation : IDeviceInfoService
    {
        public string ConvertToDeviceShortDateFormat(DateTime inputDateTime)
        {
            var dateFormat = Android.Text.Format.DateFormat.GetDateFormat(Android.App.Application.Context);
            var epochDateTime = Helper.ConvertDateTimeToUnixTime(inputDateTime, true);

            if (epochDateTime == null)
            {
                return string.Empty;
            }

            using (var javaDate = new Java.Util.Date((long)epochDateTime))
            {
                return dateFormat.Format(javaDate);
            }
        }

        public string ConvertToDeviceTimeFormat(DateTime inputDateTime)
        {
            var timeFormat = Android.Text.Format.DateFormat.GetTimeFormat(Android.App.Application.Context);
            var epochDateTime = Helper.ConvertDateTimeToUnixTime(inputDateTime, true);

            if (epochDateTime == null)
            {
                return string.Empty;
            }

            using (var javaDate = new Java.Util.Date((long)epochDateTime))
            {
                return timeFormat.Format(javaDate);
            }
        }
    }
}

iOS:

[assembly: Dependency(typeof(DeviceInfoServiceImplementation))]
namespace iOS.Services
{
    public class DeviceInfoServiceImplementation : IDeviceInfoService
    {
        public string ConvertToDeviceShortDateFormat(DateTime inputDateTime)
        {
            var timeInEpoch = Helper.ConvertDateTimeToUnixTime(inputDateTime);

            if (timeInEpoch == null)
            {
                return string.Empty;
            }

            using (var dateInNsDate = NSDate.FromTimeIntervalSince1970((double)timeInEpoch))
            {
                using (var formatter = new NSDateFormatter
                {
                    TimeStyle = NSDateFormatterStyle.None,
                    DateStyle = NSDateFormatterStyle.Short,
                    Locale = NSLocale.CurrentLocale
                })
                {
                    return formatter.ToString(dateInNsDate);
                }
            }
        }

        public string ConvertToDeviceTimeFormat(DateTime inputDateTime)
        {
            var timeInEpoch = Helper.ConvertDateTimeToUnixTime(inputDateTime);

            if (timeInEpoch == null)
            {
                return string.Empty;
            }

            using (var dateInNsDate = NSDate.FromTimeIntervalSince1970((double)timeInEpoch))
            {
                using (var formatter = new NSDateFormatter
                {
                    TimeStyle = NSDateFormatterStyle.Short,
                    DateStyle = NSDateFormatterStyle.None,
                    Locale = NSLocale.CurrentLocale
                })
                {
                    return formatter.ToString(dateInNsDate);
                }
            }
        }
    }
}

Windows:

[assembly: Dependency(typeof(DeviceInfoServiceImplementation))]
namespace WinPhone.Services
{
    public class DeviceInfoServiceImplementation : IDeviceInfoService
    {
        public string ConvertToDeviceShortDateFormat(DateTime inputDateTime)
        {
            return inputDateTime.ToShortDateString();
        }

        public string ConvertToDeviceTimeFormat(DateTime inputDateTime)
        {
            return inputDateTime.ToShortTimeString();
        }
    }
}

Helper方法:

private static readonly DateTime EpochDateTime = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
public static long? ConvertDateTimeToUnixTime(DateTime? date, bool isDatarequiredInMilliSeconds = false, DateTimeKind dateTimeKind = DateTimeKind.Local) => date.HasValue == false
            ? (long?)null
            : Convert.ToInt64((DateTime.SpecifyKind(date.Value, dateTimeKind).ToUniversalTime() - EpochDateTime).TotalSeconds) * (isDatarequiredInMilliSeconds ? 1000 : 1);

将Xamarin表单中的DateTime格式化为设备格式字符串

相关推荐