Xamarin 形成日期时间选择器

Question

我在网上找到了一个自定义渲染器，但出现错误。有谁知道如何进行日期时间控制？目前我使用单独的日期选择器和时间选择器，但我希望将它们组合在一起。

我将在下面发布我从另一篇文章中找到的代码。这是Xamarin Forms 发布日期和时间选择器的链接

using System;

using Foundation;
using Test;
using Test.Droid;
using UIKit;
using ObjCRuntime;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;

[assembly:ExportRenderer(typeof(MyPicker), typeof(MyPickerRenderer))]
namespace Test.Droid
{
public class MyPickerRenderer : PickerRenderer
{

    string SelectedValue;

    [Obsolete]
    public MyPickerRenderer()
    {

    }

    protected override void OnElementChanged(ElementChangedEventArgs<Picker> e)
    {
        base.OnElementChanged(e);

        if (Control != null)
        {
            SetTimePicker();
        }

    }


    void SetTimePicker()
    {
        UIDatePicker picker = new UIDatePicker
        {
            Mode = UIDatePickerMode.DateAndTime
        };

        picker.SetDate(NSDate.Now, true);

        picker.AddTarget(this, new Selector("DateChange:"), UIControlEvent.ValueChanged);

        Control.InputView = picker;


        UIToolbar toolbar = (UIToolbar)Control.InputAccessoryView;

        UIBarButtonItem done = new UIBarButtonItem("Done", UIBarButtonItemStyle.Done, (object sender, EventArgs click) =>
        {
            Control.Text = SelectedValue;
            toolbar.RemoveFromSuperview();
            picker.RemoveFromSuperview();
            Control.ResignFirstResponder();
            MessagingCenter.Send<Object, string>(this, "pickerSelected", SelectedValue);



        });

        UIBarButtonItem empty = new UIBarButtonItem(UIBarButtonSystemItem.FlexibleSpace, null);

        toolbar.Items = new UIBarButtonItem[] { empty, done };

    }

    [Export("DateChange:")]
    void DateChange(UIDatePicker picker)
    {
        NSDateFormatter formatter = new NSDateFormatter();

        formatter.DateFormat = "MM-dd HH:mm aa"; //you can set the format as you want

        Control.Text = formatter.ToString(picker.Date);

        SelectedValue = formatter.ToString(picker.Date);

        MessagingCenter.Send<Object, string>(this, "pickerSelected", SelectedValue);
      }
   }
}

Answer 1

让 DateTimePicker 继承一个ContentView而不是仅仅一个条目，然后创建 Stacklayout，将条目以及日期和时间选择器添加到内容中。

请参阅 DateTimePicker2.cs：

  public class DateTimePicker2 : ContentView, INotifyPropertyChanged
{
    public Entry _entry { get; private set; } = new Entry();
    public DatePicker _datePicker { get; private set; } = new DatePicker() { MinimumDate = DateTime.Today, IsVisible = false };
    public TimePicker _timePicker { get; private set; } = new TimePicker() { IsVisible = false };
    string _stringFormat { get; set; }
    public string StringFormat { get { return _stringFormat ?? "dd/MM/yyyy HH:mm"; } set { _stringFormat = value; } }
    public DateTime DateTime
    {
        get { return (DateTime)GetValue(DateTimeProperty); }
        set { SetValue(DateTimeProperty, value); OnPropertyChanged("DateTime"); }
    }

    private TimeSpan _time
    {
        get
        {
            return TimeSpan.FromTicks(DateTime.Ticks);
        }
        set
        {
            DateTime = new DateTime(DateTime.Date.Ticks).AddTicks(value.Ticks);
        }
    }

    private DateTime _date
    {
        get
        {
            return DateTime.Date;
        }
        set
        {
            DateTime = new DateTime(DateTime.TimeOfDay.Ticks).AddTicks(value.Ticks);
        }
    }

    BindableProperty DateTimeProperty = BindableProperty.Create("DateTime", typeof(DateTime), typeof(DateTimePicker2), DateTime.Now, BindingMode.TwoWay, propertyChanged: DTPropertyChanged);

    public DateTimePicker2()
    {
        BindingContext = this;

        Content = new StackLayout()
        {
            Children =
            {
                _datePicker,
                _timePicker,
                _entry
            }
        };

        _datePicker.SetBinding<DateTimePicker2>(DatePicker.DateProperty, p => p._date);
        _timePicker.SetBinding<DateTimePicker2>(TimePicker.TimeProperty, p => p._time);
        _timePicker.Unfocused += (sender, args) => _time = _timePicker.Time;
        _datePicker.Focused += (s, a) => UpdateEntryText();

        GestureRecognizers.Add(new TapGestureRecognizer()
        {
            Command = new Command(() => _datePicker.Focus())
        });
        _entry.Focused += (sender, args) =>
        {
            Device.BeginInvokeOnMainThread(() => _datePicker.Focus());
        };
        _datePicker.Unfocused += (sender, args) =>
        {
            Device.BeginInvokeOnMainThread(() =>
            {
                _timePicker.Focus();
                _date = _datePicker.Date;
                UpdateEntryText();
            });
        };
    }

    private void UpdateEntryText()
    {
        _entry.Text = DateTime.ToString(StringFormat);
    }

    static void DTPropertyChanged(BindableObject bindable, object oldValue, object newValue)
    {
        var timePicker = (bindable as DateTimePicker2);
        timePicker.UpdateEntryText();
    }
}

Xaml 中的用法：

<StackLayout>
        <local:DateTimePicker2></local:DateTimePicker2>
    </StackLayout>