C# - Gridview Bound To Filenames In Directory

I'm having some evils trying to get my GridView control to behave. I have the below code, which successfully displays all the files in the directory. However I require two changes, both of which I am struggling with:

a) Currently the URL you get when clicking on the URL field is [URL] (ie my home directory with the filename). What I require is that the 'Display Text' be the filename only, and the URL be my desired text followed by the filename eg: [URL]

b) I want only to see the files that start with a certain prefix eg "Pay". I can do that with something like: string[] filelist = Directory.GetFiles((@"C:MFData","Pay*.*"); but this doesn't like to bind to my Gridview!

const string DocumentFolderPhysicalPath = (@"C:MFData");
const string DocumentFolderUrl = (@"C:MFData"); [URL]; ; // now it is hardcoded but you could retreive it automatically
HyperLinkField hyperLinkField = new HyperLinkField();
hyperLinkField.DataTextField = "Name";
hyperLinkField.DataNavigateUrlFields = new string[] { "Name" };
//Would like this to work!
//HyperLinkField hyperLinkField2 = new HyperLinkField();
//hyperLinkField2.DataTextField = "Destination";
//hyperLinkField2.DataNavigateUrlFields = new string[] { (@"C:MFData") + "Name" };
GridView1.DataSource = GetDocuments(DocumentFolderPhysicalPath);
GridView1.Columns.Add(hyperLinkField);
GridView1.DataBind();

private System.IO.FileInfo[] GetDocuments(string physicalPath)
{
System.IO.DirectoryInfo directory =
new System.IO.DirectoryInfo(physicalPath);
if (directory.Exists)
{
return directory.GetFiles();
}
else
{
throw new System.IO.DirectoryNotFoundException(physicalPath);
}
}