转移.net core 3.1，为.NET 5做准备

Infrastructure/Helpers/GenericHelper.cs

@@ -0,0 +1,75 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Infrastructure.Helpers
+{
+    /// <summary>
+    /// List转成Tree
+    /// <para>李玉宝新增于2016-10-09 19:54:07</para>
+    /// </summary>
+    public static class GenericHelpers
+    {
+        /// <summary>
+        /// Generates tree of items from item list
+        /// </summary>
+        /// 
+        /// <typeparam name="T">Type of item in collection</typeparam>
+        /// <typeparam name="K">Type of parent_id</typeparam>
+        /// 
+        /// <param name="collection">Collection of items</param>
+        /// <param name="idSelector">Function extracting item's id</param>
+        /// <param name="parentIdSelector">Function extracting item's parent_id</param>
+        /// <param name="rootId">Root element id</param>
+        /// 
+        /// <returns>Tree of items</returns>
+        public static IEnumerable<TreeItem<T>> GenerateTree<T, K>(
+            this IEnumerable<T> collection,
+            Func<T, K> idSelector,
+            Func<T, K> parentIdSelector,
+            K rootId = default(K))
+        {
+            foreach (var c in collection.Where(u =>
+            {
+                var selector = parentIdSelector(u);
+                return (rootId == null && selector == null)  
+                || (rootId != null &&rootId.Equals(selector));
+            }))
+            {
+                yield return new TreeItem<T>
+                {
+                    Item = c,
+                    Children = collection.GenerateTree(idSelector, parentIdSelector, idSelector(c))
+                };
+            }
+        }
+        /// <summary>
+        /// 把数组转为逗号连接的字符串
+        /// </summary>
+        /// <param name="data"></param>
+        /// <param name="Str"></param>
+        /// <returns></returns>
+        public static string ArrayToString(dynamic data, string Str)
+        {
+            string resStr = Str;
+            foreach (var item in data)
+            {
+                if (resStr != "")
+                {
+                    resStr += ",";
+                }
+
+                if (item is string)
+                {
+                    resStr += item;
+                }
+                else
+                {
+                    resStr += item.Value;
+
+                }
+            }
+            return resStr;
+        }
+    }
+}