canvas rectangle generate

PacticeSolution/MVVMCanvasRectangle/ViewModel/RectModelView.cs

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+using MVVMCanvasRectangle.Model;
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.ComponentModel;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace MVVMCanvasRectangle.ViewModel
+{
+    internal class RectModelView : INotifyPropertyChanged
+    {
+        private int _count;
+        public ObservableCollection<RectItem> RectItems { get; set; }
+
+        public event PropertyChangedEventHandler? PropertyChanged;
+
+        public int Count
+        {
+            get { return _count; }
+            set
+            {
+                _count = value;
+                this.RectItems.Clear();
+                for (int i = 0; i < _count; i++)
+                {
+                    this.RectItems.Add(new RectItem { X = i * 40, Y = 10, Width = 30, Height = 30 });
+                }
+            }
+        }
+
+        public RectModelView()
+        {
+            _count = 0;
+            this.RectItems = new ObservableCollection<RectItem>();
+        }
+
+        public void AddOne()
+        {
+            RectItem lastRect = this.RectItems.LastOrDefault();
+            if (lastRect == null)
+                this.RectItems.Add(new RectItem() { X = 0, Y = 10, Width = 30, Height = 30 });
+            else
+                this.RectItems.Add(new RectItem() { X = lastRect.X + 40, Y = 10, Width = 30, Height = 30 });
+        }
+    }
+}