Any way to clear/flush/remove OutputCache?
asp.net, caching
Solution
You can use the `VaryByCustom` parameter for this.
In your user control you would have the following:
<%@ OutputCache Duration="1000" VaryByParam="None" VaryByCustom="MyKey" %>
Then you would override the `GetVaryByCustomString` method in your Global.asax like so:
public override string GetVaryByCustomString(HttpContext context, string arg)
{
if (arg == "MyKey")
{
object o = context.Current.Application["MyGuid"];
if (o == null)
{
o = Guid.NewGuid();
context.Current.Application["MyGuid"] = o;
}
return o.ToString();
}
return base.GetVaryByCustomString(context, arg);
}
Finally in `MyPage.aspx` you would do this:
Application["MyGuid"] = Guid.NewGuid();
How does this work?
Whenever your control is cached, it is associated with a string (the string returned from the `GetVaryByCustomString` method when your control's `VaryByCustom` key is passed into it).
Whenever the control is subsequently used, `GetVaryByCustomString` is called again. If the returned string matches a cached version of the control, then the cached version is used.
In our case, "MyKey" is passed into `GetVaryByCustomString` and it returns whatever is stored in `Application["MyGuid"]`.
Whenever `MyPage.aspx` is called, it changes `Application["MyGuid"]` to a new random value.
When your control is next used the `GetVaryByCustomString` method will return the new value, and because there is no cached version of the control associated with that value, the control will be regenerated. (The control will then be cached and associated with the new value, to persist until the next call to `MyPage.aspx` etc)
There's an overview here.
Problem
I'm using the OutputCache on my webuser control (.ascx) ``` <%@ OutputCache Duration="1000" VaryByParam="none" %> ``` I would like to retain the cache for next 1000 seconds, but when a specific page on my site is loaded, I would like to remove/flush/refresh the cache. Like, I want to clear the cache when MyPage.aspx is loaded. Can i flush the cache programmetically? Its only one page being cache so there are no paramatrized versions to flush cache with. Thanks for your help in advance.