Error when using LINQ to dataset

[user1980]

Hi,

I am using LINQ to join two different datatables. I am trying to put the result in a dataset.

This code was working fine till yesterday. But today when I run the code, it gives me the error,

Unable to cast object of type '<JoinIterator> d__61`4[System.Data.Dat aRow,System.Dat a.DataRow,Syste m.Decimal,VB$An onymousType_0`1 0[System.Decimal, System.DateTime ,System.DateTim e,System.DateTi me,System.DateT ime,System.Deci mal,System.Deci mal,System.Stri ng,System.Strin g,System.String]]' to type 'System.Data.Da taSet'."

I am not sure why it is not working. My code is as below. Please guide me. thank you

  Dim dt2 As New DataTable
            dt2.Load(dr2)
            Dim dt3 As New DataTable
            dt3.Load(dr3)
          Dim ds As New DataSet

          

         Dim joinquery = From t1 In dt2.AsEnumerable() Join t2 In dt3.AsEnumerable() _
                    On t1.Field(Of Decimal)("CLASS_NUMBER") Equals t2.Field(Of Decimal)("CLASS_NUMBER") _
                    Select New With _
                      {Key .CLASS_NUMBER = t1.Field(Of Decimal)("CLASS_NUMBER"), _
                       Key .FACULTY_START_DT = t2.Field(Of DateTime)("FACULTY_START_DT"), _
                       Key .FACULTY_END_DT = t2.Field(Of DateTime)("FACULTY_END_DT"), _
                       }
             
     ds = joinquery
             

            NewDg.DataSource = ds
            NewDg.DataBind()