2007年9月小记
1、GridView导出Excel
StringWriter sw = new StringWriter();
HtmlTextWriter hw = new HtmlTextWriter(sw);
this.grvColumnLogList.RenderControl(hw);
Response.Clear();
Response.ContentType = "application/vnd.ms-excel";
Response.Charset = "utf-8";
Page.EnableViewState = false;
Response.AppendHeader("Content-Disposition", "attachment;filename=MyExcel.xls");
Response.Write("<html><head><meta http-equiv=Content-Type content=\"text/html; charset=utf-8\"><title>Copyright by CJB</title></head><body><center>");
Response.Write(sw.ToString());
Response.Write("</center></body></html>");
Response.End();
需要添加以下override
public override void VerifyRenderingInServerForm(Control control)
{
}
http://www.cnblogs.com/stswordman/archive/2006/08/24/485641.html
http://www.cnblogs.com/powerlc/archive/2005/08/27/223989.html
2、CheckBoxList的全选。
<script type="text/javascript" language="javascript">
function doSelectThis(cbl)
{
var flag = true;
var iterms = cbl.getElementsByTagName('input');
for(i=0; i<iterms.length;i++)
{
if(!iterms[i].checked)
{
flag = false;
}
}
var cb = $get('<%= chbAllSelected.ClientID %>');
cb.checked = flag ? true : false;
}
function doSelectAll(obj)
{
var cbl = $get('<%= cblColumns.ClientID %>');
var iterms = cbl.getElementsByTagName('input');
for(i=0; i<iterms.length;i++)
{
if(iterms[i].getAttribute('type') == 'checkbox')
{
iterms[i].checked = obj.checked ? true : false;
}
}
}
</script>
<asp:CheckBoxList ID="cblColumns" runat="server" RepeatColumns="5" RepeatDirection="Horizontal" onclick="doSelectThis(this)" ></asp:CheckBoxList>
<asp:CheckBox ID="chbAllSelected" runat="server" Text="全选" onclick="doSelectAll(this);" />
3、固定form的action，避免在多段URL重写的无刷新分页中出现404错误
Sys.Application.add_load(function()
{
var form = Sys.WebForms.PageRequestManager.getInstance()._form;
var href = window.location.href;
form._initialAction = href;
form.action = href;
});
4、302与301对搜索引擎的影响。
301 redirect: 301代表永久性转移(Permanently Moved)，301重定向是网页更改地址后对搜索引擎友好的最好方法，只要不是暂时搬移的情况,都建议使用301来做转址。
302 redirect: 302代表暂时性转移(Temporarily Moved )，在前些年，不少Black Hat SEO曾广泛应用这项技术作弊，目前，各大主要搜索引擎均加强了打击力度，象Google前些年对Business.com以及近来对BMW德国网站的惩罚。即使网站客观上不是spam，也很容易被搜寻引擎容易误判为spam而遭到惩罚。
而Response.Redirect方法返回的正是302，如果对于永久性移除的URL，并且希望它在SEC的记录转移到新的URL中，需要改为301重写向
例如：
protected void Page_Load(object sender, EventArgs e)
{
RedirectPermanently("Page1.aspx");
}
public void RedirectPermanently(string url)
{
HttpContext context = HttpContext.Current;
context.Response.Status = "301 Moved Permanently";
context.Response.AddHeader("Location", ResolveUrl(url));
context.Response.End();
}
5、 如何利用客户端缓存对网站进行优化?
protected void Page_Load(object sender, EventArgs e)
{
int secondsTime = 10;
if (Request.Headers["If-Modified-Since"] != null &&
TimeSpan.FromTicks(DateTime.Now.Ticks - DateTime.Parse(Request.Headers["If-Modified-Since"]).Ticks).Seconds < secondsTime)
{
Response.Write(DateTime.Now);
Response.StatusCode = 304;
//Response.Headers.Add("Content-Encoding", "gzip");
Response.StatusDescription = "Not Modified";
}
else
{
Response.Write(DateTime.Now);
SetClientCaching(Response, DateTime.Now);
}
}
private void SetClientCaching(HttpResponse response, DateTime lastModified)
{
response.Cache.SetETag(lastModified.Ticks.ToString());
response.Cache.SetLastModified(lastModified);
response.Cache.SetCacheability(HttpCacheability.Public);
response.Cache.SetMaxAge(new TimeSpan(7, 0, 0, 0));
response.Cache.SetSlidingExpiration(true);
}
private void SetFileCaching(HttpResponse response, string fileName)
{
response.AddFileDependency(fileName);
response.Cache.SetETagFromFileDependencies();
response.Cache.SetLastModifiedFromFileDependencies();
response.Cache.SetCacheability(HttpCacheability.Public);
response.Cache.SetMaxAge(new TimeSpan(7, 0, 0, 0));
response.Cache.SetSlidingExpiration(true);
}
7、在SQL2005里如何清空事务日志文件？
先把数据库属性改成“简单”，然后收缩日志文件
8、获取随机记录
select * from table order by newid()
StringWriter sw = new StringWriter(); HtmlTextWriter hw = new HtmlTextWriter(sw); this.grvColumnLogList.RenderControl(hw); Response.Clear(); Response.ContentType = "application/vnd.ms-excel"; Response.Charset = "utf-8"; Page.EnableViewState = false; Response.AppendHeader("Content-Disposition", "attachment;filename=MyExcel.xls"); Response.Write("<html><head><meta http-equiv=Content-Type content=\"text/html; charset=utf-8\"><title>Copyright by CJB</title></head><body><center>"); Response.Write(sw.ToString()); Response.Write("</center></body></html>"); Response.End(); public override void VerifyRenderingInServerForm(Control control) {
}http://www.cnblogs.com/stswordman/archive/2006/08/24/485641.html
http://www.cnblogs.com/powerlc/archive/2005/08/27/223989.html
2、CheckBoxList的全选。
<script type="text/javascript" language="javascript"> function doSelectThis(cbl) { var flag = true; var iterms = cbl.getElementsByTagName('input'); for(i=0; i<iterms.length;i++) {
if(!iterms[i].checked) { flag = false; } } var cb = $get('<%= chbAllSelected.ClientID %>'); cb.checked = flag ? true : false; } function doSelectAll(obj) { var cbl = $get('<%= cblColumns.ClientID %>'); var iterms = cbl.getElementsByTagName('input'); for(i=0; i<iterms.length;i++) { if(iterms[i].getAttribute('type') == 'checkbox') { iterms[i].checked = obj.checked ? true : false; } } } </script> <asp:CheckBoxList ID="cblColumns" runat="server" RepeatColumns="5" RepeatDirection="Horizontal" onclick="doSelectThis(this)" ></asp:CheckBoxList> <asp:CheckBox ID="chbAllSelected" runat="server" Text="全选" onclick="doSelectAll(this);" />3、固定form的action，避免在多段URL重写的无刷新分页中出现404错误
Sys.Application.add_load(function() { var form = Sys.WebForms.PageRequestManager.getInstance()._form; var href = window.location.href; form._initialAction = href; form.action = href; });4、302与301对搜索引擎的影响。
301 redirect: 301代表永久性转移(Permanently Moved)，301重定向是网页更改地址后对搜索引擎友好的最好方法，只要不是暂时搬移的情况,都建议使用301来做转址。
302 redirect: 302代表暂时性转移(Temporarily Moved )，在前些年，不少Black Hat SEO曾广泛应用这项技术作弊，目前，各大主要搜索引擎均加强了打击力度，象Google前些年对Business.com以及近来对BMW德国网站的惩罚。即使网站客观上不是spam，也很容易被搜寻引擎容易误判为spam而遭到惩罚。
而Response.Redirect方法返回的正是302，如果对于永久性移除的URL，并且希望它在SEC的记录转移到新的URL中，需要改为301重写向
例如：
protected void Page_Load(object sender, EventArgs e) { RedirectPermanently("Page1.aspx"); } public void RedirectPermanently(string url) { HttpContext context = HttpContext.Current; context.Response.Status = "301 Moved Permanently"; context.Response.AddHeader("Location", ResolveUrl(url)); context.Response.End(); }5、 如何利用客户端缓存对网站进行优化?
protected void Page_Load(object sender, EventArgs e) { int secondsTime = 10; if (Request.Headers["If-Modified-Since"] != null && TimeSpan.FromTicks(DateTime.Now.Ticks - DateTime.Parse(Request.Headers["If-Modified-Since"]).Ticks).Seconds < secondsTime) { Response.Write(DateTime.Now); Response.StatusCode = 304; //Response.Headers.Add("Content-Encoding", "gzip"); Response.StatusDescription = "Not Modified"; } else { Response.Write(DateTime.Now); SetClientCaching(Response, DateTime.Now); } } private void SetClientCaching(HttpResponse response, DateTime lastModified) { response.Cache.SetETag(lastModified.Ticks.ToString()); response.Cache.SetLastModified(lastModified); response.Cache.SetCacheability(HttpCacheability.Public); response.Cache.SetMaxAge(new TimeSpan(7, 0, 0, 0)); response.Cache.SetSlidingExpiration(true); } private void SetFileCaching(HttpResponse response, string fileName) { response.AddFileDependency(fileName); response.Cache.SetETagFromFileDependencies(); response.Cache.SetLastModifiedFromFileDependencies(); response.Cache.SetCacheability(HttpCacheability.Public); response.Cache.SetMaxAge(new TimeSpan(7, 0, 0, 0)); response.Cache.SetSlidingExpiration(true); }7、在SQL2005里如何清空事务日志文件？
先把数据库属性改成“简单”，然后收缩日志文件
8、获取随机记录
select * from table order by newid()
