Linq join select all columns and CopyToDataTable - vb.net

Question

TABLE SCHEMA I'm having trouble solving a query in linq to dataset; I have to make a simple left join between two datatable but I do not know in advance the exact number of columns in the datatable B (A, B, C ...?) so I wanted to select all the columns; I found the following link
select-all-columns-after-join-in-linq
select-all-columns-for-all-tables-in-join-linq-join
Dim Query = From A In TableA _
Join B In TableB _
On A("COD") Equals B("COD") _
Select New With {A, B}
Dim TableC As DataTable = Query.CopyToDataTable()
I tried also
Select New With {.DAT = A.ItemArray.Concat(P.ItemArray).ToArray()}).ToList
and many more but i failed to bring the query result to a new datatable; I received type conversion errors or i did not understand how to bring the query result provided in two separate tables into one datatable.

Answer 1

Creating some extension methods and using Reflection will do what you want, though this may not be the ideal way to solve your issue (generally, Reflection never is).
Public Module SomeExt
<System.Runtime.CompilerServices.Extension()>
Public Function GetTypedValue(Of TProp)(ByVal p As PropertyInfo, obj As Object) As TProp
Return DirectCast(p.GetValue(obj), TProp)
End Function
<System.Runtime.CompilerServices.Extension()>
Public Function FlattenToDataTable(Of T)(src As IEnumerable(Of T)) As DataTable
Dim ans = New DataTable()
Dim srcdtpis = GetType(T).GetProperties().Cast(Of PropertyInfo)().ToList()
For Each aDT As DataTable In srcdtpis.Select(Function(pi) pi.GetTypedValue(Of DataRow)(src.First()).Table)
For Each col In aDT.Columns.Cast(Of DataColumn)()
ans.Columns.Add(col.ColumnName, col.DataType)
Next
Next
For Each drs In src
Dim newDR = ans.NewRow
For Each aDR In srcdtpis.Select(Function(pi) pi.GetTypedValue(Of DataRow)(drs))
For Each colname In aDR.Table.Columns.Cast(Of DataColumn)().Select(Function(dc) dc.ColumnName)
newDR(colname) = aDR(colname)
Next
Next
ans.Rows.Add(newDR)
Next
Return ans
End Function
End Module
You would use it as follows:
Dim Query = From A In TableA.AsEnumerable() _
Join B In TableB.AsEnumerable() _
On A("COD") Equals B("COD") _
Select New With {A, B}
Dim TableC As DataTable = Query.FlattenToDataTable()
Note that duplicate column names will be set to the last DataTable's value.