GridViewSelectedValue.aspx font size:
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<html>
<head>
<title>GridView SelectedValue Example</title>
<link rel="stylesheet" href="/shared/netdemos.css">
</head>

<body>
<!-- #include virtual="~/shared/top.inc" -->
<div class="header"><h2>GridView <span class="hilite">SelectedValue</span> Example</h2></div>
<hr size=1 width=92%>

<div align="center">
<form runat="server">
<table width="90%" cellpadding=10>
<tr valign="top">
   <td width="40%" align="center">
      Select Subject: <asp:dropdownlist id="lstTypes" runat="server" 
         datasourceid="bookTypes" 
         datatextfield="Type" 
         autopostback />

      <p>

      <asp:gridview id="gvTitles" width=100% runat="server"
         datasourceid="bookTitles"
         datakeynames="title_id"
         autogeneratecolumns=false
         gridlines="both" cellpadding=5 font-size="10pt">

         <headerstyle backcolor="lightsteelblue" font-bold />

         <selectedrowstyle backcolor="beige" font-italic />

         <columns>
            <asp:buttonfield headertext="Title"
               datatextfield="Title"
               commandname="Select" />

            <asp:boundfield headertext="TitleID" 
               datafield="title_id" />

            <asp:boundfield headertext="Price" 
               datafield="price" 
               dataformatstring="{0:c}" />

            </columns>
      </asp:gridview>

   </td>

   <td width="55%">

      <asp:formview id="fvDetails" runat="server"
         datasourceid="bookDetails">

         <itemtemplate>
            <div class="header"><h3 style="color:maroon">
               <%# Eval ( "title" ) %>
            </h2></div>

            <table cellpadding=5>
            <tr>
               <td valign="top">
                  <img align="top" runat="server"
                     src='<%# Eval ( "title_id", "~/shared/images/title-{0}.gif" ) %>'>
               </td>

               <td valign="top">
                  <p><%# Eval ( "notes" ) %></p>

                  <p>
                  <b>Category:</b> <%# Eval ( "type" ) %><br>
                  <b>Publisher ID:</b> <%# Eval ( "pub_id" ) %><br>
                  <b>Price:</b> <%# Eval ( "price", "{0:c}" ) %>
                  </p>
               </td></tr>
            </table><br>
         </itemtemplate>

      </asp:formview>

   </td></tr>
</table>

<asp:sqldatasource id="bookTypes" runat="server"
   datasourcemode="datareader"
   selectcommand="SELECT DISTINCT Type FROM Titles" 
   connectionstring="<%$ ConnectionStrings:aspnet %>" />

<asp:sqldatasource id="bookTitles" runat="server"
   selectcommand="SELECT * FROM Titles"
   filterexpression="Type='{0}'"
   connectionstring="<%$ ConnectionStrings:aspnet %>">

   <filterparameters>
      <asp:controlparameter controlid="lstTypes" 
         propertyname="SelectedValue" />
   </filterparameters>
</asp:sqldatasource>

<asp:sqldatasource id="bookDetails" runat="server"
   datasourcemode="datareader"
   selectcommand="SELECT * FROM Titles WHERE title_id = @title_id"
   connectionstring="<%$ ConnectionStrings:aspnet %>">

   <selectparameters>
      <asp:controlparameter controlid="gvTitles" 
         name="title_id" type="string"
         propertyname="SelectedValue" />
   </selectparameters>
</asp:sqldatasource>

</form>
</div>

<hr size=1 width=92%>
<!-- #include virtual="~/shared/viewsrc.inc" -->

</body>
</html>