Question

I thought I had got this to work before, but I just don’t see it:

discounts is a Dictionary<PartType, double>. data is a List<PartType>.

var d = discounts.Keys.SelectMany(
    k =>
    data.Where( l => l.PartTypeID.Equals( k.PartTypeID ) ) )
    .Select( s => new { k, l } );

The error is, the name ‘k’ (and ‘l’) does not exist in the current context.

What I eventually want to do is apply the double from the dictionary to all the matching PartTypes in data.

Answer 1

I suspect you mean:

var d = discounts.Keys.SelectMany(
    k => data.Where(l => l.PartTypeID.Equals(k.PartTypeID)),
    (k, l) => new { k, l });

… but it’s hard to tell without more information. To be honest it looks like you really want a join, e.g.

var d = discounts.Keys.Join(data,
           k => k.PartTypeID, // Key from discounts.Keys
           l => l.PartTypeID, // Key from data
           (k, l) => new { k, l }); // Projection from the two values