重写了节点的view、viewmodel关系，实现了对画布元素的选取功能，重构了底层依赖，添加了对net .Framework4.6.1以上的Framework类库支持

Library.Framework/NodeFlow/Tool/TcsSignal.cs

@@ -0,0 +1,65 @@
+using Serein.Library.Enums;
+using System;
+using System.Collections.Concurrent;
+using System.Threading.Tasks;
+
+namespace Serein.Library.Framework.NodeFlow.Tool
+{
+    public class TcsSignalException : Exception
+    {
+        public FlowStateType FsState { get; set; }
+        public TcsSignalException(string message) : base(message)
+        {
+            FsState = FlowStateType.Error;
+        }
+    }
+
+    public class TcsSignal<TSignal> where TSignal : struct, Enum
+    {
+        //public ConcurrentDictionary<TSignal, Queue<TaskCompletionSource<object>>> TcsEvent { get; } = new();
+        public ConcurrentDictionary<TSignal, TaskCompletionSource<object>> TcsEvent { get; } = new ConcurrentDictionary<TSignal, TaskCompletionSource<object>>();
+
+        public ConcurrentDictionary<TSignal, object> TcsLock { get; } = new ConcurrentDictionary<TSignal, object>();
+
+        /// <summary>
+        /// 触发信号
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="signal">信号</param>
+        /// <param name="value">传递的参数</param>
+        /// <returns>是否成功触发</returns>
+        public bool TriggerSignal<T>(TSignal signal, T value)
+        {
+            var tcsLock = TcsLock.GetOrAdd(signal, new object());
+            lock (tcsLock)
+            {
+                if (TcsEvent.TryRemove(signal, out var waitTcs))
+                {
+                    waitTcs.SetResult(value);
+                    return true;
+                }
+                return false;
+            }
+        }
+
+        public TaskCompletionSource<object> CreateTcs(TSignal signal)
+        {
+            var tcsLock = TcsLock.GetOrAdd(signal, new object());
+            lock (tcsLock)
+            {
+                var tcs = TcsEvent.GetOrAdd(signal, new TaskCompletionSource<object>());
+                return tcs;
+            }
+            
+        }
+
+        public void CancelTask()
+        {
+            foreach (var tcs in TcsEvent.Values)
+            {
+                tcs.SetException(new TcsSignalException("任务取消"));
+            }
+            TcsEvent.Clear();
+        }
+    }
+}