To get the url of the selected file

Question

 Hi,

 

  Sorry I am new to .net and would like to know  how to get a url of the selected file from a website on to a textbox when a button is clicked using the code behind.

  <asp:TextBox ID="txtfilPath" runat="server" ClientIDMode="Static" TextMode="SingleLine" Width="269px">

<asp:Button ID="fileselect" runat="server" Text="Select File" OnClick="fileselect" /> 

Thank you,