You can use FolderBrowserDialog
to select Xml Files root Directory, then:
FolderBrowserDialog fd = new FolderBrowserDialog();
DialogResult result = fd.ShowDialog();
if(result == DialogResult.OK)
{
string[] files = Directory.GetFiles(fd.SelectedPath)
.Where(p => p.EndsWith(".xml"))
.ToArray();
foreach(var path in files)
{
XDocument xDoc = XDocument.Load(path);
// read Xml file
}
}