ObjectDataSource and CacheKeyDependency possible bug

Question

I have noticed a quite strange behavior with an ObjectDataSource using CacheKeyDependency

When I set the CacheKeyDependency in the declarative .aspx syntax, the ObjectDataSource.Selecting event (and Selected) gets called twice!!! (and of course also the related Database SelectMethod gets called twice)

But, if I remove the CacheKeyDependency the ObjectDataSource Selecting Event occurs, correctly, only once!

Speed concerning apart, this could potentially break my code-behind logic if I assume that Selecting/Selected gets called only once...

Have any of you noticed that?

This behavior could be ascribed to a bug in ASP.NET or maybe there some bug in my code?

PS: The timeline of the events are like so, with in bold the duplicated ones:

PageLoad

ODS_Selecting

DataLayer Select

ODS_Selected

ODS_Filtering

GridView_DataBound

**ODS_Selecting**

**DataLayer Select**

**ODS_Selected**

ODS_Filtering

GridView_DataBound

GridView_PreRender

Answer 1

The Cache value for the CacheKeyDependency must be set. If not, the ObjectDataSource cache is essentially disabled, which can result in the select method being called twice.

See the example in the Microsoft documentation.

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        Cache[ObjectDataSource2.CacheKeyDependency] = "CacheExample";
    }
}

Found the following approach to work the best. The MS example expires the cache when the page load is not a post back.

if (null == Cache[ObjectDataSource2.CacheKeyDependency])
{
    Cache[ObjectDataSource2.CacheKeyDependency] = new Object();
}