初学者提问

first.htm
<html>
<head><title></title>
</head>
<body>
<center>
<form action="get1.aspx" method="post" >
<input type="text" name="nickname"><br>
<input type="submit" value="发送">
</form>
</center>
</body>
</html>get1.aspx
<%@ Page Language="C#" ContentType="text/html" ResponseEncoding="gb2312" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
</head>
<body>
<%
String Nickname=Request.Form["nickname"];
Response.Write(Nickname);
%>
</body>
</html>
为什么get1.aspx接收不到first.htm传来的nickname,如果我把post改成get,
Request.Form改成Request.QueryString就可以接收到