54 lines
1.8 KiB
C#
54 lines
1.8 KiB
C#
namespace Unosquare.Swan.Components
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{
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using System;
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#if NETSTANDARD1_3
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using System.Reflection;
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#endif
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/// <summary>
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/// Represents an active subscription to a message.
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/// </summary>
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public sealed class MessageHubSubscriptionToken
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: IDisposable
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{
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private readonly WeakReference _hub;
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private readonly Type _messageType;
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/// <summary>
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/// Initializes a new instance of the <see cref="MessageHubSubscriptionToken"/> class.
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/// </summary>
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/// <param name="hub">The hub.</param>
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/// <param name="messageType">Type of the message.</param>
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/// <exception cref="System.ArgumentNullException">hub.</exception>
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/// <exception cref="System.ArgumentOutOfRangeException">messageType.</exception>
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public MessageHubSubscriptionToken(IMessageHub hub, Type messageType)
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{
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if (hub == null)
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{
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throw new ArgumentNullException(nameof(hub));
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}
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if (!typeof(IMessageHubMessage).IsAssignableFrom(messageType))
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{
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throw new ArgumentOutOfRangeException(nameof(messageType));
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}
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_hub = new WeakReference(hub);
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_messageType = messageType;
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}
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/// <inheritdoc />
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public void Dispose()
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{
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if (_hub.IsAlive && _hub.Target is IMessageHub hub)
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{
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var unsubscribeMethod = typeof(IMessageHub).GetMethod(nameof(IMessageHub.Unsubscribe),
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new[] {typeof(MessageHubSubscriptionToken)});
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unsubscribeMethod = unsubscribeMethod.MakeGenericMethod(_messageType);
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unsubscribeMethod.Invoke(hub, new object[] {this});
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}
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GC.SuppressFinalize(this);
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}
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}
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} |