Max Katz
6 years ago
committed by
GitHub
GitHub
34 changed files with 806 additions and 120 deletions
@ -1,41 +0,0 @@ |
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using System; |
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using System.Globalization; |
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using System.Reflection; |
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using System.Windows.Input; |
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using Avalonia.Utilities; |
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|
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namespace Avalonia.Data.Converters |
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{ |
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class AlwaysEnabledDelegateCommand : ICommand |
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{ |
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private readonly Delegate action; |
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private ParameterInfo parameterInfo; |
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public AlwaysEnabledDelegateCommand(Delegate action) |
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{ |
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this.action = action; |
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var parameters = action.Method.GetParameters(); |
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parameterInfo = parameters.Length == 0 ? null : parameters[0]; |
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} |
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#pragma warning disable 0067
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public event EventHandler CanExecuteChanged; |
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#pragma warning restore 0067
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public bool CanExecute(object parameter) => true; |
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public void Execute(object parameter) |
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{ |
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if (parameterInfo == null) |
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{ |
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action.DynamicInvoke(); |
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} |
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else |
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{ |
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TypeUtilities.TryConvert(parameterInfo.ParameterType, parameter, CultureInfo.CurrentCulture, out object convertedParameter); |
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action.DynamicInvoke(convertedParameter); |
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} |
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} |
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} |
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} |
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@ -0,0 +1,230 @@ |
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using System; |
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using System.ComponentModel; |
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using System.Globalization; |
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using System.Linq; |
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using System.Linq.Expressions; |
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using System.Reflection; |
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using System.Windows.Input; |
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using Avalonia.Utilities; |
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namespace Avalonia.Data.Converters |
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{ |
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class MethodToCommandConverter : ICommand |
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{ |
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readonly static Func<object, bool> AlwaysEnabled = (_) => true; |
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readonly static MethodInfo tryConvert = typeof(TypeUtilities) |
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.GetMethod(nameof(TypeUtilities.TryConvert), BindingFlags.Public | BindingFlags.Static); |
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readonly static PropertyInfo currentCulture = typeof(CultureInfo) |
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.GetProperty(nameof(CultureInfo.CurrentCulture), BindingFlags.Public | BindingFlags.Static); |
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readonly Func<object, bool> canExecute; |
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readonly Action<object> execute; |
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readonly WeakPropertyChangedProxy weakPropertyChanged; |
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readonly PropertyChangedEventHandler propertyChangedEventHandler; |
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readonly string[] dependencyProperties; |
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public MethodToCommandConverter(Delegate action) |
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{ |
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var target = action.Target; |
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var canExecuteMethodName = "Can" + action.Method.Name; |
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var parameters = action.Method.GetParameters(); |
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var parameterInfo = parameters.Length == 0 ? null : parameters[0].ParameterType; |
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if (parameterInfo == null) |
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{ |
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execute = CreateExecute(target, action.Method); |
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} |
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else |
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{ |
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execute = CreateExecute(target, action.Method, parameterInfo); |
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} |
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var canExecuteMethod = action.Method.DeclaringType.GetRuntimeMethods() |
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.FirstOrDefault(m => m.Name == canExecuteMethodName |
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&& m.GetParameters().Length == 1 |
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&& m.GetParameters()[0].ParameterType == typeof(object)); |
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if (canExecuteMethod == null) |
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{ |
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canExecute = AlwaysEnabled; |
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} |
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else |
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{ |
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canExecute = CreateCanExecute(target, canExecuteMethod); |
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dependencyProperties = canExecuteMethod |
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.GetCustomAttributes(typeof(Metadata.DependsOnAttribute), true) |
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.OfType<Metadata.DependsOnAttribute>() |
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.Select(x => x.Name) |
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.ToArray(); |
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if (dependencyProperties.Any() |
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&& target is INotifyPropertyChanged inpc) |
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{ |
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propertyChangedEventHandler = OnPropertyChanged; |
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weakPropertyChanged = new WeakPropertyChangedProxy(inpc, propertyChangedEventHandler); |
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} |
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} |
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} |
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void OnPropertyChanged(object sender,PropertyChangedEventArgs args) |
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{ |
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if (string.IsNullOrWhiteSpace(args.PropertyName) |
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|| dependencyProperties?.Contains(args.PropertyName) == true) |
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{ |
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Threading.Dispatcher.UIThread.Post(() => CanExecuteChanged?.Invoke(this, EventArgs.Empty) |
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, Threading.DispatcherPriority.Input); |
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} |
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} |
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#pragma warning disable 0067
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public event EventHandler CanExecuteChanged; |
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#pragma warning restore 0067
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public bool CanExecute(object parameter) => canExecute(parameter); |
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public void Execute(object parameter) => execute(parameter); |
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static Action<object> CreateExecute(object target |
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, System.Reflection.MethodInfo method) |
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{ |
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var parameter = Expression.Parameter(typeof(object), "parameter"); |
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var instance = Expression.Convert |
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( |
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Expression.Constant(target), |
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method.DeclaringType |
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); |
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var call = Expression.Call |
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( |
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instance, |
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method |
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); |
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return Expression |
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.Lambda<Action<object>>(call, parameter) |
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.Compile(); |
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} |
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static Action<object> CreateExecute(object target |
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, System.Reflection.MethodInfo method |
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, Type parameterType) |
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{ |
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var parameter = Expression.Parameter(typeof(object), "parameter"); |
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var instance = Expression.Convert |
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( |
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Expression.Constant(target), |
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method.DeclaringType |
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); |
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Expression body; |
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if (parameterType == typeof(object)) |
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{ |
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body = Expression.Call(instance, |
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method, |
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parameter |
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); |
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} |
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else |
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{ |
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var arg0 = Expression.Variable(typeof(object), "argX"); |
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var convertCall = Expression.Call(tryConvert, |
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Expression.Constant(parameterType), |
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parameter, |
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Expression.Property(null, currentCulture), |
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arg0 |
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); |
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var call = Expression.Call(instance, |
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method, |
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Expression.Convert(arg0, parameterType) |
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); |
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body = Expression.Block(new[] { arg0 }, |
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convertCall, |
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call |
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); |
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} |
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Action<object> action = null; |
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try |
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{ |
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action = Expression |
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.Lambda<Action<object>>(body, parameter) |
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.Compile(); |
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} |
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catch (Exception ex) |
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{ |
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throw ex; |
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} |
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return action; |
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} |
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static Func<object, bool> CreateCanExecute(object target |
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, System.Reflection.MethodInfo method) |
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{ |
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var parameter = Expression.Parameter(typeof(object), "parameter"); |
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var instance = Expression.Convert |
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( |
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Expression.Constant(target), |
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method.DeclaringType |
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); |
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var call = Expression.Call |
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( |
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instance, |
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method, |
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parameter |
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); |
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return Expression |
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.Lambda<Func<object, bool>>(call, parameter) |
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.Compile(); |
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} |
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internal class WeakPropertyChangedProxy |
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{ |
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readonly WeakReference<PropertyChangedEventHandler> _listener = new WeakReference<PropertyChangedEventHandler>(null); |
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readonly PropertyChangedEventHandler _handler; |
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internal WeakReference<INotifyPropertyChanged> Source { get; } = new WeakReference<INotifyPropertyChanged>(null); |
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public WeakPropertyChangedProxy() |
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{ |
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_handler = new PropertyChangedEventHandler(OnPropertyChanged); |
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} |
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public WeakPropertyChangedProxy(INotifyPropertyChanged source, PropertyChangedEventHandler listener) : this() |
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{ |
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SubscribeTo(source, listener); |
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} |
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public void SubscribeTo(INotifyPropertyChanged source, PropertyChangedEventHandler listener) |
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{ |
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source.PropertyChanged += _handler; |
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Source.SetTarget(source); |
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_listener.SetTarget(listener); |
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} |
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public void Unsubscribe() |
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{ |
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if (Source.TryGetTarget(out INotifyPropertyChanged source) && source != null) |
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source.PropertyChanged -= _handler; |
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Source.SetTarget(null); |
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_listener.SetTarget(null); |
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} |
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void OnPropertyChanged(object sender, PropertyChangedEventArgs e) |
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{ |
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if (_listener.TryGetTarget(out var handler) && handler != null) |
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handler(sender, e); |
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else |
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Unsubscribe(); |
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} |
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} |
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} |
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} |
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