LINQ in .NET 2010. - DynamicLinq Queries

Question

Hi everyone,

The request is to buiild a page on which I shall represent all the avaliable fields of a view that can be used by the user in order to build the query that will run by itself. I have done it and I am at the point that I have to create the LINQ select.

In my page at the bigining I have imported the following:

Imports WorkAtXYZ.NewNS.Linq.Dynamic
Imports System.Linq.Expressions

In order to construct the Select I use a function which investigate in my checkbox list all the items, and get the name of the fields for the selected ones.

Finaly, my Select is the following :

New(fldCorporateKey, fldFirstName, fldLastName, fldNormalDays_Remaining)

and I proceed:

 Private Sub btnRunQuery_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnRunQuery.Click
        Dim cont As New workatXYZEntities_views
        Dim vw_Results As IQueryable
Dim strSELECT As String = ConstructSELECT()
vw_Results = cont.vw_AbsencesReportingModel.Select(strSELECT).Distinct

and here I am getting the following error:

'New' cannot be resolved into a valid type or function. Near simple identifier, line 2, column 8.

Could you please help me? Is there something that I do not see?

Thank you in advance.

Answer 1

Hi Anastasios,

I tested your code but cannot call Distinct() method after Select() method.

It works fine for me If I test the code like:

vw_Results = cont.vw_AbsencesReportingModel.Distinct().Select(strSELECT)

Best regards,

---

Chester Hong
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Answer 2

Hi Chester, 

Thank you very much for you answer and this is something that also others (from other forums) have answered me. But the issue is not solved. And as I have told you your proposal is matched with what also others propose to me as a solution. 

I am still getting the same error. So I'll to give some more information on the project. 

I have read that I have to include the following namespace in order to be able to have DynicLINQ Queries. 

Imports WorkAtXYZ.NewNS.Linq.Dynamic
Imports System.Linq.Expressions

In the import above the posts was telling me that it is Syste.Linq.Dynamic but I do so, something is bypassed or replaced and in every file I have to include namespaces manually so I found this work around. 

The whole function is the following: 

 Private Sub btnRunQuery_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnRunQuery.Click

        Dim cont As New workatXYZEntities_views
        Dim vw_Results As Object

        divResults.Visible = True
        divEntitySelector.Visible = False
        divRebuild.Visible = True

        Dim QueryToRun As Collection = ConstructQuery("Absences")

        Dim strWHERE As String = QueryToRun.Item(1).ToString
        Dim strSELECT As String = QueryToRun.Item(2).ToString

        If strWHERE <> "" Then
            vw_Results = cont.vw_AbsencesReportingModel.Where(strWHERE).Distinct().Select(strSELECT)
        Else
            vw_Results = cont.vw_AbsencesReportingModel.Distinct().Select(strSELECT)
        End If


        grdResults.DataSource = vw_Results
        grdResults.DataBind()

    End Sub

Could you please check it for a while?