CODEWITHSUNDEEP
vb.netlinq-to-sql
Xaisoft
Xaisoft

Reputation: 46651

Convert the following VB code to a LINQ statement?

I only want to return a certain number of rows into the DataTable via LINQ's Take or use it on the Rows property, but I am not sure how or where to do it: Here is the current code:

 Dim dt As DataTable = GetDataTable("sp", params)
 For Each dr As DataRow In dt.Rows
        Dim o As New OR()
        o.P = p
        o.Id = dr ("A")
        o.R = dr ("B")
 Next

Would it be something like:

Dim dt As DataTable = GetDataTable("sp", params).AsEnumerable().Take(10)

When I run the above, I get the error:

The 'TakeIterator' start tag on line 4 position 60 does not match the end tag of 'Error'. Line 4, position 137.

Unable to cast object of type '<TakeIterator>d__3a1[System.Data.DataRow]' to type 'System.Data.DataTable'.`

Upvotes: 0

Views: 702

Answers (1)

Tim Schmelter
Tim Schmelter

Reputation: 460288

If you need a DataTable:

Dim dt As DataTable = (From row in GetDataTable("sp", params) Take 10).CopyToDataTable()

If you need a List(Of [Or]) (you need the brackets since Or is a keyword)

Dim list As List(Of [Or]) = (From row In GetDataTable("sp", params)
                            Select New [Or]() {
                                o.Id = row.Field(Of Int32)("Id"),
                                o.R =  row.Field(Of String)("R")
                            }).Take(10).ToList()

Edit:

is there a way I can also include a Where with the Take, for example, I have 3 statuses in my table, Open, Semi-Open, Closed, I only want to Take 10 for Open, but I want to leave Semi-Open and Closed alone. As an example Semi-Open and Closed will have 5 records combined and I will take 10 from Open, so I would get a total of 15 rows

Yes, there's a way:

Dim dt =  GetDataTable("sp", params)
Dim open10 = From row In dt
             Where row.Field(Of String)("Status") = "Open"
             Take 10
Dim rest = From row In dt
           Where row.Field(Of String)("Status") <> "Open"
Dim tblResult = open10.Concat(rest).CopyToDataTable()

Upvotes: 1

Related Questions