Requirements for design-time data source in Report Viewer 2010

What are the requirements for a custom data source to be listed in the 'Data Source' drop-down list when adding a Dataset to a .rdlc report in Report Viewer 2010?

As can been seen from the screen grab, for some reason it is listing potential sources from a variety of r开发者_运维百科eferenced assemblies, but I can't see an obvious pattern as to why it is selecting these.

The 'GeneralDataSet' makes sense as that is a strongly-typed Dataset class, but I'm pretty sure most of the others are not, yet the design dialog still lists them.

I'm looking to roll my own custom data source and would prefer it to be selectable from this list.

I think it scans your project file looking for methods that return Lists<> and so on.

So something like:

public class Person
{
    public string name { get; set; }
    public int age { get; set; }
}

public class GetPeople
{
   public List<Person> GetPeopleList()
   {
      return null;
   }

   public IEnumerable<Person> GetPeopleIEnumerable()
   {
      return null;
   }

   public IQueryable<Person> GetPeopleIQueryable()
   {
      return null;
   }
}

All three show up, so take your pick. (Code is just thrashed out, ignore bad names/practices :))

But when you use a ReportViewer, you will need to manually set the datasets. Selecting it inside the report from what I have found just basically tells it what data to expect. So add an ObjectDataSource or just set it in the code behind.

I noticed the dataset does not appear if the source is exposed as a Property and not a method.

ie this fails to be a selectable data source.

public class FooData 
{
    public List<string> Data {get;set;}
}

but this will show up as a data source

public class FooData 
{
    public List<string> GetData();
}

I just had a problem with this also,

my class was returning Lists but would not show up in the datasources list.

I then added a parameterless constructor and it started to show up ( there was not one before ) I assmume this is so the reportviewer can create and instance of it.

eg:

public MyObject()
{
}

I've had a similar problem with custom lists which inherit from List. You can work around it if your system will allow you to inherit without using interfaces. Ours doesn't.

The project containing this class WILL appear in the DataSource dropdown, and the class itself appears in the DataSet dropdown:

public class AccountList : List<AccountData>
{}

This class will NOT appear as a Dataset, which prevents its project from appearing as a DataSource (notice the "I" in front of AccountData):

public class AccountList : List<IAccountData>
{}

This is a pain because other aspects of our system require the lists to inherit from an interface not a concrete class. I don't know why it doesn't work.