getting info for hyperlink clicked

Question

I am having troble displaying relevant information for a clicked hyperlink .

I have a table "Course" and "StudentInfo"

My Hyperlinks display list courses from DB* table(Course.table) and when  I click  one Hyperlink, the program has to get information for that link clicked from database

and display whether in a gridview or label  (It has to check which hyperlink is clicked i guess)  

this is how I display my hyperlinks from DB*

<asp:gridview id="mygv" 

                autogeneratecolumns="false"

        runat="server">

        <columns>

            <asp:hyperlinkfield datatextfield="hyperlink"

            datatextformatstring="{0:c}"

            datanavigateurlfields="hyperlink"

            datanavigateurlformatstring="~\WebForm1.aspx?hyperlink={0}"          

            headertext=""

            />

               </columns>

      </asp:gridview>

 if (!IsPostBack)

            {

 BindGrid(mygv);

}

 try

              {

                  SqlCommand cmd = new SqlCommand(" SELECT [hyperlink] FROM Courses WHERE [Student ID] = '" + Session["StudentID"] + "'", con);

                  con.Open();

                  SqlDataReader dr = cmd.ExecuteReader();

                  if (dr.HasRows)

                  {

                      mygv.DataSource = dr;

                      mygv.DataBind();

                  }

                  else

                  {

                      mygv.DataSource = null;

                      mygv.DataBind();

                  }

              }

              catch (Exception ex)

              {

                  Response.Write("Error Occured: " + ex.ToString());

              }

              finally

              {

                  con.Close();

              }

how do I get the information for the link clicked??