The least-cost way to return a one-row IEnumerable object?

[Guest]

The function must return a IEnumerable object with one row (any data). I have
the following code. Any less cost way?

IEnumerable^ udf()
{
DataTable dt;
dt.Columns->Add("Test");
dt.Rows->Add(1);
return dt.Rows;
}

 

[Marcus Heege]

How about

IEnumerable^ udf()
{
return gcnew cli::array<Object^> { yourOneAndOnlyElement };
}

 

[Guest]

I am thinking some constant object so there is no runtime gcnew....?

 

[Marcus Heege]

I am thinking some constant object so there is no runtime gcnew....?

IEnumerable^ is a tracking handle. Tracking handles can only refer to
objects on the garbage collected heap. Objects on the garbage collected heap
are created with gcnew (or boxing, which is not relevant here). So the
answer to your question is: No, there is no way to avoid creating an object
on the gc heap if you want to return IEnumerable^.

Marcus