43 строки
1.6 KiB
C#
43 строки
1.6 KiB
C#
using System;
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using System.ComponentModel;
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using System.Linq;
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using System.Reflection;
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using System.Runtime.InteropServices.WindowsRuntime;
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using Windows.UI.Xaml;
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using Xamarin.Forms.Internals;
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namespace Xamarin.Forms.Platform.UWP
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{
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class NativeEventWrapper : INotifyPropertyChanged
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{
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static string TargetProperty { get; set; }
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static readonly MethodInfo s_handlerinfo = typeof(NativeEventWrapper).GetRuntimeMethods().Single(mi => mi.Name == nameof(OnPropertyChanged) && mi.IsPublic == false);
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public NativeEventWrapper(object target, string targetProperty, string updateSourceEventName)
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{
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TargetProperty = targetProperty;
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try {
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var updateSourceEvent = target.GetType().GetRuntimeEvent(updateSourceEventName);
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MethodInfo addMethod = updateSourceEvent.AddMethod;
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MethodInfo removeMethod = updateSourceEvent.RemoveMethod;
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ParameterInfo[] addParameters = addMethod.GetParameters();
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Type delegateType = addParameters[0].ParameterType;
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var handlerDelegate = s_handlerinfo.CreateDelegate(delegateType, this);
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Func<object, EventRegistrationToken> add = a => (EventRegistrationToken)addMethod.Invoke(target, new object[] { handlerDelegate });
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Action<EventRegistrationToken> remove = t => removeMethod.Invoke(target, new object[] { t });
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WindowsRuntimeMarshal.AddEventHandler(add, remove, s_handlerinfo);
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}
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catch (Exception) {
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Log.Warning(nameof(NativeEventWrapper), "Can not attach NativeEventWrapper.");
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}
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}
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void OnPropertyChanged(object sender, RoutedEventArgs e)
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{
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PropertyChanged?.Invoke(sender, new PropertyChangedEventArgs(TargetProperty));
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}
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public event PropertyChangedEventHandler PropertyChanged;
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}
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}
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