string[] array = { "A","B","C","D","H"};
var index=array.ToList().IndexOf("D");使用IndexOf()方法，返回数组元素在数组中的索引。
index=3;
string[] array = { "A","B","C","D","H"};
var index=array.ToList().IndexOf("D"); index=3;原文：https://www.cnblogs.com/redhairboy/p/9062712.html