1. 重新设计了Generate项目及相关特性的命名，避免与其他类型混淆。

2. 补充了部分注释。
3. 修改了删除容器节点时，容器内子节点未正确删除的问题。

NodeFlow/Model/Operations/SetStartNodeOperation.cs

@@ -0,0 +1,82 @@
+using Serein.Library;
+using Serein.Library.Api;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Serein.NodeFlow.Model.Operations
+{
+    /// <summary>
+    /// 设置起始节点
+    /// </summary>
+    internal class SetStartNodeOperation : OperationBase
+    {
+        public override string Theme => nameof(SetStartNodeOperation);
+
+
+        public string CanvasGuid { get; set; }
+        public string NewNodeGuid { get; set; }
+
+
+        private FlowCanvasDetails CanvasModel;
+        private IFlowNode NewStartNodeModel;
+        private IFlowNode? OldStartNodeModel;
+
+
+        public override bool ValidationParameter()
+        {
+            if (!flowModelService.TryGetCanvasModel(CanvasGuid, out CanvasModel)
+                || !flowModelService.TryGetNodeModel(NewNodeGuid, out NewStartNodeModel))
+            {
+                return false;
+            }
+            return true;
+        }
+        public override async Task<bool> ExecuteAsync()
+        {
+            if (!ValidationParameter()) return false;
+
+            if (CanvasModel.StartNode is not null
+                && flowModelService.TryGetNodeModel(CanvasModel.StartNode.Guid, out var flowNode)) 
+            {
+                OldStartNodeModel = flowNode;
+            }
+
+            CanvasModel.StartNode = NewStartNodeModel;
+
+            await TriggerEvent(() =>
+            {
+                flowEnvironmentEvent.OnStartNodeChanged(new StartNodeChangeEventArgs(CanvasModel.Guid, OldStartNodeModel?.Guid, NewStartNodeModel.Guid));
+            });
+            return true;
+        }
+
+        public override bool Undo()
+        {
+            if(OldStartNodeModel is null)
+            {
+                return false;
+            }
+            var newStartNode = OldStartNodeModel;
+            var oldStartNode = NewStartNodeModel;
+
+            NewStartNodeModel = newStartNode;
+            OldStartNodeModel = oldStartNode;
+            CanvasModel.StartNode = oldStartNode;
+
+            flowEnvironmentEvent.OnStartNodeChanged(new StartNodeChangeEventArgs(CanvasModel.Guid, oldStartNode?.Guid, newStartNode.Guid));
+            return true;
+
+        }
+
+
+        public override void ToInfo()
+        {
+            throw new NotImplementedException();
+        }
+
+       
+    }
+}