Creating file in vs 13 for windows app

Question

I want to create a csv file in the root folder for my app. The file should be created only if it doesn't exist, if it exists it should just add data in new line in the same file.

Answer 1

You can't rely on creating files where your programme is installed.
Most users will not have create permission nowadays.
You can easily prove this yourself.
Open file explorer.
navigate to a folder under programs where you have something installed.
Right click on an empty bit and choose New on the menu.
On my win8.1 machine I see Folder as the only option.
They changed this since I think Win7 but maybe also Vista. 
You should use AppData.
This helper gets you the location of Appdata on the machine and adds your programme's namespace for a folder within that:
public static class AppData
public static string Location = Path.Combine(Environment.GetFolderPath(
Environment.SpecialFolder.ApplicationData), System.Reflection.Assembly.GetExecutingAssembly().EntryPoint.DeclaringType.Namespace);
This code here is serialising an object to FontDetails.xml in such a folder:
private void Application_Exit(object sender, ExitEventArgs e)
var fileName = Path.Combine(AppData.Location, "FontDetails.xml");
if (!Directory.Exists(AppData.Location))
Directory.CreateDirectory(AppData.Location);
FontDetails fd = Application.Current.Resources["FontDetails"] as FontDetails;
DataContractSerializer ser = new DataContractSerializer(typeof(FontDetails));
var xmlSettings = new XmlWriterSettings { Indent = true, IndentChars = "\t" };
using (var writer = XmlWriter.Create(fileName, xmlSettings))
ser.WriteObject(writer, fd);
Hope that helps.
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