C# getting the path of %AppData%

Question

Hello,

C# 2008 SP1

I am using this code below:

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

However, I am getting an exception that point 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.

Many thanks for any advice,

Answer 1

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

Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)

%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

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

try

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

Answer 3

I think you can also use Environment.ExpandEnvironmentVariables("%AppData%\DateLinks.xml"); to expand the %AppData% variable.

Answer 4

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 5

In .net2.0 you can use the variable Application.UserAppDataPath