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ConsoleApp2/Helpers/Extensions.Dictionary.cs

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+namespace ConsoleApp2.Helpers;
+
+public static class DictionaryExtensions
+{
+    
+    /// <summary>
+    /// 根据指定的键是否存在来添加或是更新字典
+    /// </summary>
+    /// <param name="this"></param>
+    /// <param name="key">指定的键</param>
+    /// <param name="addValue">如果指定的键不存在，则向字典添加该值</param>
+    /// <param name="updateFactory">如果指定的键存在，则根据该委托的返回值修改字典中对应的值</param>
+    /// <typeparam name="TKey"></typeparam>
+    /// <typeparam name="TValue"></typeparam>
+    /// <returns>添加或是修改后的值</returns>
+    public static TValue AddOrUpdate<TKey, TValue>(this IDictionary<TKey, TValue> @this, TKey key, TValue addValue,
+        Func<TKey, TValue, TValue> updateFactory)
+    {
+        if (!@this.TryGetValue(key, out var value))
+        {
+            @this.Add(key, addValue);
+        }
+        else
+        {
+            @this[key] = updateFactory(key, value);
+        }
+
+        return @this[key];
+    }
+}