LocalFlowEnvironment文件丢失，需要重写

NodeFlow/Model/Operation/CreateCanvasOperation.cs

@@ -0,0 +1,51 @@
+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.Operation
+{
+    internal class CreateCanvasOperation : OperationBase
+    {
+        public override string Theme => nameof(CreateCanvasOperation);
+        public override bool IsCanUndo => false; 
+
+        public required FlowCanvasDetailsInfo CanvasInfo { get; set; }
+
+        
+
+        private FlowCanvasDetails? flowCanvasDetails;
+
+        public override bool ValidationParameter()
+        {
+            if (CanvasInfo is null) 
+                return false; // 没有必须的参数
+            if (string.IsNullOrEmpty(CanvasInfo.Guid)) 
+                return false; // 不能没有Guid
+            if(flowModelService.ContainsCanvasModel(CanvasInfo.Guid)) 
+                return false; // 画布已存在
+            return true;
+        }
+
+        public override bool Execute()
+        {
+            if(!ValidationParameter()) return false;
+
+            var cavasnModel = new FlowCanvasDetails(flowEnvironment);
+            cavasnModel.LoadInfo(CanvasInfo);
+            flowModelService.AddCanvasModel(cavasnModel);
+            this.flowCanvasDetails = cavasnModel; ;
+            flowEnvironmentEvent.OnCanvasCreated(new CanvasCreateEventArgs(cavasnModel));
+            return true;
+        }
+
+        public override void ToInfo()
+        {
+            throw new NotImplementedException();
+        }
+
+    }
+}