C# – Get temp folder path and create a temp file

You can use Path.GetTempPath() to get the user’s temp folder path. Here’s an example:

using System.IO;

var tempFolderPath = Path.GetTempPath();

Console.WriteLine(tempFolderPath);
Code language: C# (cs)

I’m running this in Windows, so it outputs my temp folder path:

C:\Users\makolyte\AppData\Local\Temp\Code language: plaintext (plaintext)

Path.GetTempPath() gets the temp folder path by checking environment variables (TMP, TEMP, USERPROFILE). It falls back to returning the system temp folder.

Create a temp file

Once you have the temp folder path, you can combine it with a file name and create a file. Here’s an example:

using System.IO;

var tempFolderPath = Path.GetTempPath();
var filePath = Path.Combine(tempFolderPath, "a.txt");

File.WriteAllText(filePath, "hello world");
Code language: C# (cs)

If you don’t need a specific temp file name, there’s a shortcut: Path.GetTempFileName(). This creates a temp file with a unique name in the temp folder and returns the file path. Internally, it uses Path.GetTempPath() to find the temp folder. Here’s an example:

using System.IO;

var tempFilePath = Path.GetTempFileName();

File.WriteAllText(tempFilePath, "hello world");

Console.WriteLine($"{tempFilePath} exists? {File.Exists(tempFilePath)}");
Console.WriteLine($"Content: {File.ReadAllText(tempFilePath)}");
Code language: C# (cs)

This example outputs the following (notice the temp file’s name):

C:\Users\makolyte\AppData\Local\Temp\tmp1C1A.tmp exists? True
Content: hello world
Code language: plaintext (plaintext)