开发中需要传递变参，考虑使用 dynamic 还是 Dictionary（准确地说是Dictionary<string,object>）。dynamic 的编码体验显著优于 Dictionary，如果性能差距不大的话，我会选择使用dynamic。搜索后没有找到类似对比数据，决定自行实验。
首先使用以下测试代码:
- public void TestDynamic()
- {
- var e = CallDynamic(new { Value = 0 });
- int v = e.Value;
- }
- public void TestDictionary()
- {
- var dict = new Dictionary<string, object>();
- dict["Value"] = 0;
- dict = CallDictionary(dict);
- int v = (int)dict["Value"];
- }
- private dynamic CallDynamic(dynamic test)
- {
- int v = test.Value;
- v++;
- return new { Value = v };
- }
- private Dictionary<string, object> CallDictionary(
- Dictionary<string, object> test)
- {
- int v = (int)test["Value"];
- v++;
- var dict = new Dictionary<string, object>();
- dict["Value"] = v;
- return dict;
- }
分别比较运行 1次、10次、100次、1000次、1e4次、1e5次、1e6次 时间
结果：
其中dynamic列和dynamic2列的数据分别是：
在一次运行中执行一步测试 和 在一次运行中连续执行所有测试
分析测试过程和数据，得到以下结论：
1.dynamic首次使用会产生一定的性能损耗
2.无论是否首次使用，使用次数达到一定量级，dynamic性能一定优于Dictionary
3.一次运行中连续使用dynamic会显著拉低平均性能损耗
考虑到传递变参可能出现多个参数，以上测试不完全。
使用以下代码进行第二阶段实验：
- public void InvokeDynamic()
- {
- var e = CallDynamic2(
- new { Value1 = 0, Value2 = 0L, Value3 = 0f, Value4 = 0.0, Value5 = "test" });
- int v1 = e.Value1;
- long v2 = e.Value2;
- float v3 = e.Value3;
- double v4 = e.Value4;
- string v5 = e.Value5;
- }
- public void InvokeDictionary()
- {
- var dict = new Dictionary<string, object>();
- dict["Value1"] = 0;
- dict["Value2"] = 0L;
- dict["Value3"] = 0f;
- dict["Value4"] = 0.0;
- dict["Value5"] = "test";
- dict = CallDictionary2(dict);
- int v1 = (int)dict["Value1"];
- long v2 = (long)dict["Value2"];
- float v3 = (float)dict["Value3"];
- double v4 = (double)dict["Value4"];
- string v5 = (string)dict["Value5"];
- }
- private dynamic CallDynamic2(dynamic test)
- {
- int v1 = test.Value1;
- long v2 = test.Value2;
- float v3 = test.Value3;
- double v4 = test.Value4;
- string v5 = test.Value5;
- v1++;
- v2++;
- v3++;
- v4++;
- v5 += "test";
- return new { Value1 = v1, Value2 = v2, Value3 = v3, Value4 = v4, Value5 = v5 };
- }
- private Dictionary<string, object> CallDictionary2(
- Dictionary<string, object> test)
- {
- int v1 = (int)test["Value1"];
- long v2 = (long)test["Value2"];
- float v3 = (float)test["Value3"];
- double v4 = (double)test["Value4"];
- string v5 = (string)test["Value5"];
- v1++;
- v2++;
- v3++;
- v4++;
- v5 += "test";
- var dict = new Dictionary<string, object>();
- dict["Value1"] = v1;
- dict["Value2"] = v2;
- dict["Value3"] = v3;
- dict["Value4"] = v4;
- dict["Value5"] = v5;
- return dict;
- }
结果数据：
最后决定选择使用dynamic
有兄弟考虑可能Box损耗了性能导致Dictionary表现不佳，
专门做了第三阶段实验，对比dynamic和Dictionary<string,long>
具体数据不贴了，结果是dynamic在100000量级快一倍
来源：51CTO
