Message displaying in .net -

I'm filling a figure in the application of my windows. The data table looks like this

I want to display a message box in this format

Should display only the first 2 products for each month, should be sorted for each month.

I hope that I have said that my problem is clear.

  select dateProducts in DP dp.Product in dp.Date G {G. Key.ToString () + "-" + string .joined (",", g.tech (2) .oerere ()) + live Quote ()> 2? ".......": ""}