delete a file before uninstall function

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C#

Visual-Studio

VS2010

setup

Hi everyone,
I have a win application that creates a xml file in runtime in the setup folder path of itself. I have created a setup for my application, but i do not know how can i delete that xml file before the application is uninstalled!!!

I have tried Installer class but it did not worked. I think the problem is that in BeforeUninstall event of it the setup folder path of the application is disposed.

Note : I have used the following code to find the setup folder of my application..

using Microsoft.Win32;

RegistryKey key = Registry.CurrentUser.OpenSubKey(@"Software\Microsoft\Installer\Assemblies");
string regfilepath="";
if (key!=null)       // Make sure there are Assemblies
{
    foreach(string Keyname in key.GetSubKeyNames())
    {
        if (Keyname.IndexOf("YOUR_EXE_FILE.EXE")>0)
        {
    regfilepath=Keyname;
    break;
        }
   }
}
string fullpath="";
for (int a=0;a<regfilepath.Length;a++)
{
  if (regfilepath.IndexOf("|",a,1)>0)
   fullpath+="\\";
 else
  fullpath+=regfilepath.Substring(a,1);
}