添加项目文件。

ExportExcelTest/Models/SubItem.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace CustomOpenAddins.Models
+{
+    /// <summary>
+    /// 二级开项
+    /// </summary>
+    public class SubItem : BaseItem
+    {
+        public SubItem(string name, PrimaryItem primary) : base(name)
+        {
+            Primary = primary;
+            DetailCategories = new HashSet<DetailItem>();
+        }
+
+        public DetailItem this[int index]
+        {
+            get => DetailCategories.ElementAt(index);
+        }
+        public PrimaryItem Primary { get; set; }
+
+        public override string ToString()
+        {
+            StringBuilder sb = new StringBuilder($"<子项>{Name};");
+            if (DetailCategories.Count == 0)
+            {
+                return sb.Append("无;").ToString();
+            }
+            foreach (var item in DetailCategories)
+            {
+                sb.AppendLine($"{item}");
+            }
+            return sb.ToString();
+        }
+
+        public HashSet<DetailItem> DetailCategories { get; private set; }
+
+        public DetailItem AddDetail(string detailName)
+        {
+            DetailItem detail = new DetailItem(detailName, this);
+            if (DetailCategories == null)
+            {
+                DetailCategories = new HashSet<DetailItem>();
+            }
+            DetailCategories.Add(detail);
+            return detail;
+        }
+        public void AddDetails(List<DetailItem> details)
+        {
+            if (DetailCategories == null)
+            {
+                DetailCategories = new HashSet<DetailItem>();
+            }
+            details.ForEach(x =>
+            {
+                x.SubItem = this;
+                DetailCategories.Add(x);
+            });
+        }
+    }
+}
+