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()