ajax.net中操作session

在服务器端page_load
AjaxPro.Utility.RegisterTypeForAjax(typeof(test));
this.Button_Write.Attributes.Add("onclick","WriteSession();");//写session
this.Button_Read.Attributes.Add("onclick", "ReadSession();");//读session
其他写和读的方法
/// <summary>
/// 写session
/// </summary>
/// <param name="str"></param>
[AjaxPro.AjaxMethod(AjaxPro.HttpSessionStateRequirement.ReadWrite)]
public void WriteSession(string str)
{
Session["UserName"] = str;
}
/// <summary>
/// 读session
/// </summary>
/// <returns></returns>
[AjaxPro.AjaxMethod(AjaxPro.HttpSessionStateRequirement.ReadWrite)]
public string ReadSession()
{
string str = "";
if (Session["UserName"] != null)
{
    str = Session["UserName"].ToString();
}
return str;
}

客户端代码：
 //4、访问Session的值
//写入
function WriteSession()
{
    var str = "HAHA";
    test.WriteSession(str,CallBack_WriteSession);
}
function CallBack_WriteSession(res)
{
    if(res.error == null)
    {
        alert("OK");
    }
    else
    {
        alert(res.error.message);
    }
}
//访问
function ReadSession()
{
    test.ReadSession(CallBack_ReadSession);
}
function CallBack_ReadSession(res)
{
    if(res.error == null)
    {
        alert(res.value);
    }
    else
    {
        alert(res.error.message);
    }
}