Question

I am using the following query to pull a row from a datatable in memory.

Dim results = _
   From myRow In exceldt.AsEnumerable() _
   Where myRow.Field(Of String)("Serial Number") = Row.Item("Serial Number") _
   Select myRow

resultrow = results.CopyToDataTable.Rows(0)

I need to get the index of the resultrow when it was part of exceldt. I can’t seem to find anything on this. Suggestions?

Answer 1

I don’t work in VB.net so forgive my code but you can get the index of a projection with something along the lines of this:

Dim result = exceldt.AsEnumerable() .Select (Function(item, index) _
  New With { .Index = index, .SerialNumber = item }).ToList 

I can’t provide much more with in VB but this quick example does work as a Console app. You can see how the select / projection captures the index and item. You will need to incorporate similar logic before filtering (where) you initial enumeration.

Dim names = {"Andy", "Tom", "Fred", "Sally"}

Dim results = names _
    .Select(Function(item, index) New With {.Index = index, .Name = item}) _
    .OrderBy(Function(item) item.Name)

For Each item In results
    Console.WriteLine("{0} - {1}", item.Index, item.Name)
Next

results

0 - Andy
2 - Fred
3 - Sally
1 - Tom