binary4cat · January 31, 2019 09:00 · Jan 31, 2019
diff --git a/DictionaryExtend.cs b/DictionaryExtend.cs
@@ -0,0 +1,52 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.Collections.Specialized;
+
+namespace iCTR.WeiXin.Common.Extensions
+{
+    /// <summary>
+    /// 字典类扩展
+    /// </summary>
+    public static class DictionaryExtend
+    {
+        /// <summary>
+        /// 根据OrderedDictionary类型的value获取key
+        /// </summary>
+        /// <typeparam name="T1">key的类型</typeparam>
+        /// <typeparam name="T2">value的类型</typeparam>
+        /// <param name="od">OrderedDictionary对象</param>
+        /// <param name="value">value</param>
+        /// <returns>key的值，如果没有则返回零值</returns>
+        public static T1 GetKeyByValue<T1,T2>(this OrderedDictionary od, T2 value)
+        {
+            foreach (DictionaryEntry o in od)
+            {
+                // 比较两个参数是否相等
+                if (EqualityComparer<T2>.Default.Equals((T2)o.Value,value))
+                {
+                    return (T1) o.Key;
+                }
+            }
+            return default(T1);
+        }
+
+        /// <summary>
+        /// 根据索引获取字典的一项
+        /// </summary>
+        /// <param name="od">有序字典</param>
+        /// <param name="i">索引</param>
+        /// <returns>字典项</returns>
+        public static DictionaryEntry GetItemByIndex(this OrderedDictionary od, int i)
+        {
+            var j = 0;
+            foreach (DictionaryEntry entry in od)
+            {
+                if (i == j++)
+                {
+                    return entry;
+                }
+            }
+            return new DictionaryEntry();
+        }
+    }
+}