DataList中用ItemCommand单击标题，出现字符串的格式不正确错误，求破解

Question

DataList中用ItemCommand实现单击新闻标题，打开一个窗体显示新闻详细信息，以及实现分页功能。但是，分页中的上一页，下一页，首页末页都可实现，唯有点击新闻标题就会出现 输入字符串的格式不正确 的错误

我的代码是这样的：
protected void dlNews_ItemCommand(object source, DataListCommandEventArgs e)
{
switch (e.CommandName)
{
case "open":
int id = Convert.ToInt32(dlNews.DataKeys[e.Item.ItemIndex].ToString());
Response.Write("window.open('ShowNews.aspx?id=" + id + "','')");
break;
case "first":
ps.CurrentPageIndex = 0;
Bind(ps.CurrentPageIndex);
break;
case "pre":
ps.CurrentPageIndex = ps.CurrentPageIndex - 1;
Bind(ps.CurrentPageIndex);
break;
case "next":
ps.CurrentPageIndex = ps.CurrentPageIndex + 1;
Bind(ps.CurrentPageIndex);
break;
case "last":
ps.CurrentPageIndex = ps.PageCount - 1;
Bind(ps.CurrentPageIndex);
break;
case "search":
if (e.Item.ItemType == ListItemType.Footer)
{
int PageCount = int.Parse(ps.PageCount.ToString());
TextBox txtPage = e.Item.FindControl("txtPage") as TextBox;
int MyPageNum = 0;
if (!txtPage.Text.Equals(""))
MyPageNum = Convert.ToInt32(txtPage.Text.ToString());
if (MyPageNum <= 0 || MyPageNum > PageCount)
Response.Write("alert(&#39;请输入页数并确定没有超出总页数！&#39;)");
else
Bind(MyPageNum - 1);
}
break;
}

}
给出了这样的错误提示：

    我是菜鸟，求大神帮帮忙看看啊