ObjectDataSourc e caching questions

[J055]

Hi

I've implemented caching for my ObjectDataSourc e.

<asp:ObjectData Source ID="ObjectDataS ource1" runat="server"
EnableCaching=" True" CacheDuration=" 10" CacheExpiration Policy="Sliding "

SelectMethod="G etUsers" TypeName="BizOb ject"></asp:ObjectDataS ource>

This works, however I need to explicitly clear/remove the cache when I
delete record(s). (It's a custom delete, not a ObjectDataSourc e builtin
one.) I understand that I need to set the CacheKeyDepende ncy property so
that I can Remove it from the cache?

When I add this line to the above the cache stops working, i.e. the
SelectMethod retrieves the data from the database each time.

CacheKeyDepende ncy="GVkey"

Can someone point me in the right direction? How do I see what's in the
cache? If I write this out it is always zero even when the cache is working.

Literal1.Text = "The number of items in the cache:" +
Cache.Count.ToS tring();

Very confused. Thanks
Andrew

[Steven Cheng[MSFT]]

Hi Andrew,

Thank you for posting.

Regarding on the ObjectDataSourc e's caching behavior , here are some of my
understanding and suggestion:

The objectDataSourc e control's cache is maintained internally so that we
can not manually view or query through the Page.Cache or HttpContext.Cac he
collection. And the cache is created and used during the Select method of
the ObjectDataSourc e, that means, when ObjectDataSourc e.Select method is
called, it will check the cache to see whether it should use cache or redo
the query from the underlying data access class. This is different from
the behavior GridView (or other databound control) call
DataSourceContr ol.Select since DataBound control may store data in
ViewState to avoid querying the datasourcecontr ol. In other word, if you
want to test the ObjectDatasourc e control's cache behavior, you can
manually call ObjectDataSourc e.Select method and also put some trace
code(like Httpcontext.Cur rent.Response.W rite...) in the data access
control's select method to check the behavior.

Also, for the "CacheKeyDepend ency", when it is set, that means the
ObjectDataSourc e.Select method will use the cached data only when there is
an existing cache entry in the application Cache and the key of it equals
to the "CacheKeyDepend ency" property wo set on the ObjectDataSourc e
control. So we need to add such a cache entry so that the ObjectDataSourc e
will use the cache, then, when we want to explicitly expire the
ObjectDataSourc e's cache, just remove that entry(we need to readd it if we
want the objectdatasourc e to begin using cache again). e.g:

<asp:ObjectData Source ID="ObjectDataS ource1" runat="server"
CacheDuration=" 10"
EnableCaching=" True" SelectMethod="G etProducts"
TypeName="TestD ataObject" CacheKeyDepende ncy="MYKEY">
............... ..

//test method to manually call ObjectDatasourc e.Select method
protected void Button1_Click(o bject sender, EventArgs e)
{
Response.Write( "<br/>Button1_Click" );
ObjectDataSourc e1.Select();
}

//manually remove the cache entry of the objectdatasourc e's KeyDependency
protected void btnInvalid_Clic k(object sender, EventArgs e)
{
Cache.Remove(Ob jectDataSource1 .CacheKeyDepend ency);
}

// set the key entry
protected void Button2_Click(o bject sender, EventArgs e)
{

Cache[ObjectDataSourc e1.CacheKeyDepe ndency] = new object();

}

Hope this helps.

Regards,

Steven Cheng
Microsoft Online Community Support
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[Manu]

Hi,

this is from a post about the ObjectDataSourc e:

"Sometimes we may need to invalidate the cached data for the
ObjectDataSourc e. To do so we can use the CacheKeyDepende ncy property.
When the control caches the data returned from the SelectMethod, it
will check the value of CacheKeyDepende ncy, and if it's set the
cached data will have a dependency on that cache key. When we want to
remove the cached data we can use the Cache.Remove method using the key
specified in the CacheKeyDepende ncy".

If you want to check the full post:

http://www.manuelabadia.com/blog/Per...2f72d0c86.aspx

The ObjectDataSourc e uses the internal cache to store data. To view the
cached data you can use Nikhil's web development helper or Cristian
Civera's ViewState Analyzer.

Hope it helps,

Manu

J055 ha escrito:

Hi

I've implemented caching for my ObjectDataSourc e.

<asp:ObjectData Source ID="ObjectDataS ource1" runat="server"
EnableCaching=" True" CacheDuration=" 10" CacheExpiration Policy="Sliding "

SelectMethod="G etUsers" TypeName="BizOb ject"></asp:ObjectDataS ource>

This works, however I need to explicitly clear/remove the cache when I
delete record(s). (It's a custom delete, not a ObjectDataSourc e builtin
one.) I understand that I need to set the CacheKeyDepende ncy property so
that I can Remove it from the cache?

When I add this line to the above the cache stops working, i.e. the
SelectMethod retrieves the data from the database each time.

CacheKeyDepende ncy="GVkey"

Can someone point me in the right direction? How do I see what's in the
cache? If I write this out it is always zero even when the cache is working.

Literal1.Text = "The number of items in the cache:" +
Cache.Count.ToS tring();

Very confused. Thanks
Andrew