convert query result to dictionary in vb.net

dictionary, linq, vb.net

Solution

As you do not have a special projection in the select, you can just call `ToDictionary` on the collection. The first lambda expression retrieves the key, the second one the value.

Dim dicQuery = toolkitEntities.currentfrontcommoditysymbols.ToDictionary( _
                   Function(x) x.ShortDesc, _
                   Function(y) y.CurrentFrontSymbol)

As for your update: the following query should get you the desired result:

Dim query = (From d In ctx.projections
             Where d.SymbolId <= 42 AndAlso d.Date >= lookbackDate
             Join t In ctx.symbols On d.SymbolId Equals t.Id
             Let actualRange = d.HighProjection - d.LowProjection
             Select New With {
                d.Date,
                d.SymbolId,
                t.Name,
                actualRange}).GroupBy(Function(o) o.SymbolId)
            .ToDictionary(Function(p) p.Key, 
                          Function(x) x.Select(Function(y) New ProjectionPerformance() With {
                              .SymbolId = Convert.ToInt32(y.SymbolId), 
                              .ProjectionDate = y.Date.ToString(), 
                              .Name = y.Name, 
                              .ProjectedRange = y.actualRange
                          }).ToList())

Problem

What is the proper syntax for .ToDictionary to return the following as a Dictionary(Of String, String) where ShortDesc is the key and CurrentFrontSymbol is the value ``` Dim dicQuery As Dictionary(Of String, String) = (From d In toolkitEntities.currentfrontcommoditysymbols Select d.ShortDesc, d.CurrentFrontSymbol) ``` Update And can the following functions query and following For Each loop become one LINQ query? ``` Public Shared Function GetRangeProjectionPerformance(Optional daysToRetrieve As Integer = 100) As Dictionary(Of Integer, List(Of ProjectionPerformance)) Dim todaysDate As Date = DateTime.Now.Date Dim lookbackDate As Date = todaysDate.AddDays(daysToRetrieve * -1) Dim temp As New Dictionary(Of Integer, List(Of ProjectionPerformance)) Using ctx As New ProjectionsEntities() Dim query = (From d In ctx.projections Where d.SymbolId <= 42 AndAlso d.Date >= lookbackDate Join t In ctx.symbols On d.SymbolId Equals t.Id Let actualRange = d.HighProjection - d.LowProjection Select New With { d.Date, d.SymbolId, t.Name, actualRange}).GroupBy(Function(o) o.SymbolId).ToDictionary(Function(p) p.Key) For Each itm In query Dim rpp As New ProjectionPerformance Dim rppList As New List(Of ProjectionPerformance) If itm.Value.Count > 0 Then For x As Integer = 0 To itm.Value.Count - 1 Dim bb As Integer = Convert.ToInt32(itm.Value(x).SymbolId) With rpp .SymbolId = bb .ProjectionDate = itm.Value(x).Date.ToString() .Name = itm.Value(x).Name .ProjectedRange = itm.Value(x).actualRange End With rppList.Add(rpp) Next End If temp.Add(itm.Key, rppList) Next End Using Return temp End Function ```

Original source