recursion error ！

最新推荐文章于 2024-11-14 17:30:39 发布

原创最新推荐文章于 2024-11-14 17:30:39 发布 · 857 阅读

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文章标签：

#recursion #exception #string #file

本文分析了一个文件重命名函数的问题所在，并提供了一种修正方案。原函数试图避免文件名重复，但存在递归调用导致的变量作用域问题，使得文件名无法正确更新。修正后的代码确保了文件名在每次冲突时都能正确地增加编号。

look following code：

private string FileRenameHandler(string dic ,string filename)

{

DirectoryInfo info = new DirectroyInfo(dic);

int count = info.GetFiles(filename);

if(count != 0)

{

filename = filename.substring(0,filename.lastindexof('.')+"("+count+")"+filename.substring(filename.lastindexof('.'));

FileRenameHandler(dic,filename);

}

return filename;

}

what we can get when we run this code?

it can generate result :

1(1).txt

why did come to this?

perhaps you have found this bug;

we rename the filename just (count!=0) ;at last the filename we get from inner filerenamehandler can't work;

filename is just the value in the first circly;

we correct it like this; private void FileNameSameHandle( string fileNameOutNotExtension,ref string fileNameNotExtension,string fileExtension) { //find the file in the appointed directory try { count++; //we can know that whatever rename filename ,if count isn't zero ,it must be one; //int count = dir.GetFiles(filename, System.IO.SearchOption.TopDirectoryOnly).Length; if (System.IO.File.Exists(PathSetting.readProfile() + "//" + fileNameNotExtension + fileExtension)) // MessageBox.Show(count.ToString()); { //local varible cause the exception ,and at last the filename can't be changed; fileNameNotExtension = fileNameOutNotExtension + "(" + count + ")"; FileNameSameHandle(fileNameOutNotExtension, ref fileNameNotExtension,fileExtension); } } catch (Exception ex) { LogHelper.WriteLog(LogHelper.LogType.Error, "rename file exception:"+ex.Message); } }