Using HyperLink in Gridview

Design View of Page
<asp:GridView ID="gvEmployee" runat="server" AutoGenerateColumns="False">
<Columns>
<asp:BoundField DataField="EmployeeID" HeaderText="Employee ID" />
<asp:BoundField DataField="FirstName" HeaderText="First Name" />
<asp:BoundField DataField="LastName" HeaderText="Last Name" />
<asp:BoundField DataField="BirthDate" HeaderText="BirthDate" />
<asp:BoundField DataField="City" HeaderText="City" />
<asp:BoundField DataField="Country" HeaderText="Country" />
<asp:TemplateField>
<ItemTemplate>
<asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl='<%#Eval("EmployeeID","Default.aspx?EmployeeID={0}") %>' Text='<%# Bind("EmployeeID") %>'></asp:HyperLink>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Code Behing of Page
SqlParameter objParameter = new SqlParameter();
SqlCommand objCommand = new SqlCommand();
SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString);
SqlDataAdapter da = new SqlDataAdapter("SELECT EmployeeID, FirstName, LastName, BirthDate, City, Country FROM Employees", conn);
//da.SelectCommand.Parameters.Add(new SqlParameter("@CustomerID", customerid));
//da.SelectCommand.Parameters["@CustomerID"].Value = customerid;
DataSet ds = new DataSet();
da.Fill(ds, "Employees");
gvEmployee.DataSource = ds;
gvEmployee.DataBind();