Question

I’ve got a Page, a GridView using an ObjectDataSource with a SelectMethod and a DropDownList. The SelectMethod, among other things, gets a string-array containing several IDs (to filter the Data) – but I also need it as DataSource for the DropDownList.
Alas, I cannot DataBind the DropDownList inside the SelectMethod since it’s null.
An Idea would be to bind this string[] to a Session-Variable, but then I’d have to either re-set it upon every Page_Load or remove it from Session on every other page if I want it to update in case something on the Database changed.

What I’m looking for is some kind of variable that is available both in Page_Load and my ObjectDataSources SelectMethod, but that removes itself upon leaving the page (i.e. navigating to any other page on my Web-Application (preferably without having to call a method on EVERY other Page).

I hope you could understand my problem.

Thanks,

Dennis

Answer 1

As I understand the need to fetch the string array arises from the performance hit that a separate roundtrip will cause. To work around this you may create a separate object to feed your object data source. This object will have two methods one for getting the string array and another for getting the data for the grid (i.e. the select method)

You may then put an object like this in your page and fetch the data in it in a lazy manner. If the object makes a call for any of the data it stores the other part in a field. You can then use the ObjectDataSource ObjectCreating event to pass this object on your page to the ObjectDataSource

protected void odsSomething_ObjectCreating(object sender, ObjectDataSourceEventArgs e)
{
    e.ObjectInstance = YourInsntanceAlreadyInThePage;
}

This way you will avoid the roundtrip.

Also consider making two web service calls at the same time using the asynchronous client calls so that you can make both calls for the same time. If this is viable depends on the flow of your logic.