Here is some code that I put together for an app I am working on that loads 2 xml files and a large csv file to a dataset at startup. It runs fairly fast, but I would like a second opinion on what I could do to either make it more consise or faster. I'm newer to .Net as well, so if you see anything that isn't very ."net ish" let me know!

Thanks

Region "Imports"

Imports System.IO
Imports System.Xml
Imports System.Text
Imports System.Threading

End Region

Class clsLoadTables

Region "Properties and Shared Variables"

Private Shared pathTableTwo As String = My.Settings.pathTableTwo
Private Shared pathMainTable As String = My.Settings.pathMainTable
Private Shared pathBeneLifeExp As String = My.Settings.pathBeneLifeExp
Private _ds As New DataSet
Public Property ds() As DataSet
    Get
        Return _ds
    End Get
    Set(ByVal value As DataSet)
        _ds = value
    End Set
End Property

End Region

Region "Constructors"

Sub New()

    loadBeneLifeExpTable()
    loadMainRMDTable()
    loadCSVTableII()

End Sub

End Region

Region "ClassMethods"

Public Sub loadCSVTableII()

    Dim dt As DataTable = ds.Tables.Add("TableII")
    Dim line As String = String.Empty
    Dim counter As Short = 0
    Dim reader As New StreamReader(pathTableTwo)
    Dim errorString As New StringBuilder

    Try
        errorString.Append("The tableII csv file did not load properly")
        errorString.Append(Environment.NewLine & Environment.NewLine)
        errorString.Append("Make syre the tabel_II.csv file is in the project folder")
    Catch ex As Exception
        Throw
    End Try

    Try
        While Not reader.EndOfStream()

            line = reader.ReadLine()
            Dim lineSep As List(Of String) = line.Split(",").ToList

            If Not counter = 0 Then
                dt.Rows.Add(lineSep.ToArray)
                counter += 1
            Else
                For Each value As String In lineSep
                    dt.Columns.Add(value)
                Next
                counter += 1
            End If

        End While

        Dim primarykey(0) As DataColumn
        primarykey(0) = dt.Columns("Ages")
        dt.PrimaryKey = primarykey

    Catch ex As FileNotFoundException
        MessageBox.Show(errorString.ToString)
        Throw
    Catch ex As Exception
        Throw
    Finally
        reader.Close()
    End Try

End Sub

Public Sub loadMainRMDTable()

    Dim tempDs As New DataSet 
    Dim dt As New DataTable
    Dim settings As New XmlReaderSettings
    Dim errorString As New StringBuilder

    Try
        errorString.Append("The RMD table did not load properly!")
        errorString.Append(Environment.NewLine & Environment.NewLine)
        errorString.Append("Make sure that the file 'MainRMDTable.xml' is in the project folder")
    Catch ex As Exception
        Throw
    End Try

    Try

        Dim xmlFile As XmlReader
        xmlFile = XmlReader.Create(pathMainTable, settings)

        tempDs.ReadXml(xmlFile)
        dt = tempDs.Tables("Age")
        dt.TableName = "MainRMDTable"

        xmlFile.Close()


        Dim primarykey(0) As DataColumn
        primarykey(0) = dt.Columns("age")
        dt.PrimaryKey = primarykey

        ds.Merge(tempDs)

    Catch ex As FileNotFoundException
        Throw
    Catch ex As Exception
        MessageBox.Show(errorString.ToString)
        Throw
    Finally
        errorString.Clear()
        tempDs.Clear()
    End Try

End Sub

Public Sub loadBeneLifeExpTable()

    Dim dt As New DataTable
    Dim settings As New XmlReaderSettings
    Dim errorString As New StringBuilder

    Try
        errorString.Append("The bene life expectancy table did not load properly ")
        errorString.Append(Environment.NewLine & Environment.NewLine)
        errorString.Append("Make sure that the file 'beneLifeExpectancyTable.xml' is in the project folder")
    Catch ex As Exception
        Throw
    End Try

    Try
        Dim xmlFile As XmlReader
        xmlFile = XmlReader.Create(pathBeneLifeExp, settings)

        ds.ReadXml(xmlFile)
        dt = ds.Tables("Age")
        dt.TableName = "BeneLifeExpectancyTable"

        xmlFile.Close()

        Dim primarykey(0) As DataColumn
        primarykey(0) = dt.Columns("BeneLifeExpectancyTable")
        dt.PrimaryKey = primarykey

    Catch ex As Exception
        MessageBox.Show(errorString.ToString)
        MessageBox.Show(ex.Message & ex.StackTrace())
        Throw
    Finally
        errorString.Clear()
    End Try

End Sub

End Region

End Class