C# list.remove 在 foreach 循环中抛出枚举操作错误

Question

我查看了多个与我相关的 SO 问题以及谷歌搜索，但我一直无法找到适合我的解决方案。

给定一个文件列表，出于某种原因，我试图剔除所有非 CS 文件。我获取字符串数组，转换为列表，并遍历列表，使用 list.Remove() 删除所有我不需要的文件。

第一次删除后，它会出错

Collection was modified; enumeration operation might not execute

代码是:

string[] files = null;
            try
            {
                files = System.IO.Directory.GetFiles(currentDir);

                //Converting to list, to use list.Remove rather than rewriting entire array at each delete
                var list = new List<string>(files);
                foreach (string readFile in list)
                {
                    if (Path.GetExtension(readFile) != ".cs") //|| Path.GetExtension(readFile) != ".dll")
                    {
                        //remove, as we don't currently care about non cs files.
                        list.Remove(readFile);
                    }
                }

                //Converting back to string array for use in the rest of the program
                files = list.ToArray();
            }

我也试过 RemoteAt()，它产生了同样的错误。

string[] files = null;
            try
            {
                files = System.IO.Directory.GetFiles(currentDir);

                //Converting to list, to use list.Remove rather than rewriting entire array at each delete
                var list = new List<string>(files);
                int i = 0;
                for(int i=0; i<list.Count();i++)
                {
                    if (Path.GetExtension(readFile) != ".cs") //|| Path.GetExtension(readFile) != ".dll")
                    {
                        //remove, as we don't currently care about non cs files.
                        list.RemoveAt(i);
                    }
                    i++;
                }

                //Converting back to string array for use in the rest of the program
                files = list.ToArray();
            }

克服此错误的任何建议，因为某些目录中将包含超过 500 个文件，我希望尽可能避免重写字符串数组。

我已阅读以下 SO 问题:

How to remove item from list in C#?

C# error Collection was modified; enumeration operation might not execute

Enumerations Foreach Loop C#

"List.Remove" in C# does not remove item?

https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.list-1.remove?view=netframework-4.8

https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.list-1.removeat?view=netframework-4.8

Answer 1

您还可以以相反的顺序使用 for 循环，这样删除的条目就不会影响循环。

for (int x = list.Count-1; x >= 0; x--)
{
  string readFile = list[x];
  // ...
  list.Remove(readFile);
}