C# in Depth

Groupings and continuations309from defect inSampleData.AllDefectsDefect: { ID=1, AssignedTo=Darren ...}Defect: { ID=2, AssignedTo=null ...}Defect: { ID=3, AssignedTo=Tara ...}Defect: { ID=4, AssignedTo=Darren ...}Defect: { ID=5, AssignedTo=Tim ...}Defect: { ID=6, AssignedTo=Darren ...}...where defect.AssignedTo != nullDefect: { ID=1, AssignedTo=Darren ...}Defect: { ID=3, AssignedTo=Tara ...}Defect: { ID=4, AssignedTo=Darren ...}Defect: { ID=5, AssignedTo=Tim ...}Defect: { ID=6, AssignedTo=Darren ...}...group defect by defect.AssignedToKey=DarrenKey=TaraKey=TimDefect: { ID=1, AssignedTo=Darren ...}Defect: { ID=4, AssignedTo=Darren ...}Defect: { ID=6, AssignedTo=Darren ...}...Defect: { ID=3, AssignedTo=Tara ...}Defect: { ID=13, AssignedTo=Tara ...}...Defect: { ID=5, AssignedTo=Tim ...}Defect: { ID=8, AssignedTo=Tim ...}...(Result of query)Figure 11.9 Sequences used when grouping defects by assignee. Eachentry of the result has a Key property and is also a sequence of defect entries.When the projection is nontrivial, a slightly more complicated version is used. Listing11.18 gives an example of a projection so that we only capture the summary ofeach defect rather than the Defect object itself.Listing 11.18Grouping defects by assignee—projection retains just the summaryvar query = from defect in SampleData.AllDefectswhere defect.AssignedTo != nullgroup defect.Summary by defect.AssignedTo;foreach (var entry in query)Licensed to Rhona Hadida