C# getting the path of %AppData%

Question

C# 2008 SP1

I am using the code below:

dt.ReadXml("%AppData%\\DateLinks.xml");

However, I am getting an exception that points to the location of where my application is running from:

Could not find a part of the path 'D:\\Projects\\SubVersionProjects\\CatDialer\\bin\\Debug\\%AppData%\\DateLinks.xml'.

I thought the %AppData% should find the relative path. When I go Start|Run|%AppData% windows explorer takes me to that directory.

I can not put the full path in, as the user is different on each client machine.

Answer 1

To get the AppData directory, it's best to use the GetFolderPath method:

Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)

(must add using System if not present).

%AppData% is an environment variable, and they are not automatically expanded anywhere in .NET, although you can explicitly use the Environment.ExpandEnvironmentVariable method to do so. I would still strongly suggest that you use GetFolderPath however, because as Johannes Rössel points out in the comment, %AppData% may not be set in certain circumstances.

Finally, to create the path as shown in your example:

var fileName = Path.Combine(Environment.GetFolderPath(
    Environment.SpecialFolder.ApplicationData), "DateLinks.xml");

Answer 2

The path is different if you're talking ASP.NET.

I couldn't find any of the 'SpecialFolder' values that pointed to /App_Data for ASP.NET.

Instead you need to do this:

 HttpContext.Current.ApplicationInstance.Server.MapPath("~/App_Data")  

(Note: You don't need the 'Current' property in an MVC Controller)

If theres another more 'abstract' way to get to App_Data would love to hear how.

Answer 3

The BEST way to use the AppData directory, IS to use Environment.ExpandEnvironmentVariables method.

Reasons:

• it replaces parts of your string with valid directories or whatever
• it is case-insensitive
• it is easy and uncomplicated
• it is a standard
• good for dealing with user input

Examples:

string path;
path = @"%AppData%\stuff";
path = @"%aPpdAtA%\HelloWorld";
path = @"%progRAMfiLES%\Adobe;%appdata%\FileZilla"; // collection of paths

path = Environment.ExpandEnvironmentVariables(path);
Console.WriteLine(path);

More info:

%ALLUSERSPROFILE%   C:\ProgramData
%APPDATA%   C:\Users\Username\AppData\Roaming
%COMMONPROGRAMFILES%    C:\Program Files\Common Files
%COMMONPROGRAMFILES(x86)%   C:\Program Files (x86)\Common Files
%COMSPEC%   C:\Windows\System32\cmd.exe
%HOMEDRIVE% C:
%HOMEPATH%  C:\Users\Username
%LOCALAPPDATA%  C:\Users\Username\AppData\Local
%PROGRAMDATA%   C:\ProgramData
%PROGRAMFILES%  C:\Program Files
%PROGRAMFILES(X86)% C:\Program Files (x86) (only in 64-bit version)
%PUBLIC%    C:\Users\Public
%SystemDrive%   C:
%SystemRoot%    C:\Windows
%TEMP% and %TMP%    C:\Users\Username\AppData\Local\Temp
%USERPROFILE%   C:\Users\Username
%WINDIR%    C:\Windows

Answer 4

You can also use

Environment.ExpandEnvironmentVariables("%AppData%\\DateLinks.xml");

to expand the %AppData% variable.

Answer 5

在 .net2.0 中，您可以使用变量Application.UserAppDataPath

Answer 6

AppData ⇝ Local aka ( C:\\Users\\<user>\\AppData\\Local ):

Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData)

---

AppData ⇝ Roaming aka ( C:\\Users\\<user>\\AppData\\Roaming ):

Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)

---

Additionally, it could be handy to know:

• Environment.SpecialFolder.ProgramFiles - for Program files X64 folder
• Environment.SpecialFolder.ProgramFilesX86 - for Program files X86 folder

For the full list check here .

Answer 7

I don't think putting %AppData% in a string like that will work.

try

Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData).ToString()

Answer 8

只是想在我的 mvc 应用程序中分享另一种访问“App_Data”文件夹的方式，以防有人需要它。

 Path.Combine(HttpRuntime.AppDomainAppPath,"App_Data")

Answer 9

这在控制台应用程序中对我有用 -

string appData = System.Environment.GetEnvironmentVariable("APPDATA");

Answer 10

For ASP.NET, the Load User Profile setting needs to be set on the app pool but that's not enough. There is a hidden setting named setProfileEnvironment in \\Windows\\System32\\inetsrv\\Config\\applicationHost.config , which for some reason is turned off by default, instead of on as described in the documentation . You can either change the default or set it on your app pool. All the methods on the Environment class will then return proper values.