How to read text file from client system ('C:\')

From following code I am able to read text from Server location 'C:\FileOnServer.txt' . But how to read text from Client Local 'C:\'

File.OPEN('C:\FileOnServer.txt');
File.CREATEINSTREAM(InStream);
TextIn.READTEXT(test);
File.CLOSE;

Warm Regards,

Ashish