为什么我不能在 LocalApplicationData 中创建文件？ C#，VS 2022，Windows 11

Question

I know that there are restrictions to file operations, but SpecialFolder.LocalApplicationData is supposed to be for application use.

string _myFilePath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "MyFile.txt"); //Line1
Console.WriteLine(_myFilePath); //Line2
Console.WriteLine(File.Exists(_myFilePath)); //Line3
Console.WriteLine(File.Create(_myFilePath)); //Line4

This is the console output:

The program stops at the 4th line and VS 2022 shows this error:

How can I create or delete files/folders in SpecialFolder.LocalApplicationData ? Or which folder is recommended for this kind of file/folder operations?

Answer 1

Using Windows 11, VS 2022 17.2.0 Preview 5.0 and.NET 6.0 without administrator privileges:
Your code worked fine for me.

Output:

C:\Users\Edgar\AppData\Local\MyFile.txt
False
System.IO.FileStream

But here is my suggestion:
Check the ACLs of your directory: Is your account permitted for creating new files?
(Right-click the directory -> Properties -> Security -> Select your own user and check your permissions.)

Usually you should not create files directly under your %localappdata% directory.
If you need a temp-file, I would recommend to use Path.GetTempFileName() for getting a unique file name.
If you want to store files for a longer time, then I would recommend to create a directory for your application in %localappdata% and save the files there.

Sample:

string myApplicationDirectory = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "MyApplication");
string myApplicationFile = Path.Combine(myApplicationDirectory, "myFile.txt");
if (!Directory.Exists(myApplicationDirectory)) {
    Console.WriteLine($"Creating directory: {myApplicationDirectory}");
    Directory.CreateDirectory(myApplicationDirectory);
}
File.Create(myApplicationFile);
Console.WriteLine($"File created: {myApplicationFile}");

Output:

Creating directory: C:\Users\Edgar\AppData\Local\MyApplication  
File created: C:\Users\Edgar\AppData\Local\MyApplication\myFile.txt