Linq with if Condition and Datatable Update

[ppr (Peter Preuss)]

In general a Group By Case which we can handle as described here:

[HowTo] Overview on different options for grouping data and processing the groups

This HowTo introduces on the different options for grouping data from a datatable in order to process the grouped data. Introduction Grouping data and processing the grouped data is a common scenario e.g. when the grouped data is to aggregate like summing up, find maximum, get the average or concatening items. Lets have a look on following data: [grafik] A possible scenario could be: Create a report containing following information: the region code the sum of CaseCount per RegionCode t…

We would recommend to start with a hybrid approach

Groups | DataType: List(of (ListOf DataRow)) =

(From d in dtData.AsEnumerable
Group d by k1=d("InvoiceNo.").toString.Trim, k2=d("MATERIAL CODE.").toString.Trim into grp = Group
Select x=grp.ToList).toList

outer List = Groups, inner List = Group Members

For Each Activity (not for each row activity) | grp = Groups | TypeArgument: List(Of DataRow)

• Assign Activity
  strAVG = grp.Average(Function (x) CDbl(x(“Price”).toString.Trim)).toString(“F2”)

• For Each Activity (not for each row activity) | mbr in grp | TypeArgument: DataRow

  • Assign Activity: mbr(“Price”) = strAVG

When DataColumn Price defines a Not Object/String Datatype then we just would little adapt