C# Online Compiler | .NET Fiddle

Imports System
Imports System.Xml
Imports System.Data
				
Public Module Module1
	Public Sub Main()
        ' Get a DataTable instance from helper function.
        Dim table As DataTable = GetTable()
		
'		Console.WriteLine("Table rows = " & table.Rows.Count)
		
'		For Each row As DataRow In table.Rows
'            ' Write value of first Integer.
'			Console.WriteLine(row(0))
'        Next
	
		Dim sql As String = "Dosage > 0" 
		Dim rows() As DataRow = table.Select(sql)
		
		For Each row As DataRow In rows
			' Convert and write first value
			row(0) = Convert.ToInt32(row(0))
			Console.WriteLine(row(0))
        Next
		
		
    End Sub

    ''' <summary>
    ''' Helper function that creates new DataTable.
    ''' </summary>
    Function GetTable() As DataTable
        ' Create new DataTable instance.
        Dim table As New DataTable

        ' Create four typed columns in the DataTable.
        'table.Columns.Add("Dosage", GetType(Integer))
		table.Columns.Add("Dosage", GetType(Decimal))
        table.Columns.Add("Drug", GetType(String))
        table.Columns.Add("Patient", GetType(String))
        table.Columns.Add("Date", GetType(DateTime))

        ' Add five rows with those columns filled in the DataTable.
        table.Rows.Add(25, "Indocin", "David", DateTime.Now)
        table.Rows.Add(50, "Enebrel", "Sam", DateTime.Now)
        table.Rows.Add(10, "Hydralazine", "Christoff", DateTime.Now)
        table.Rows.Add(21.5, "Combivent", "Janet", DateTime.Now)
        table.Rows.Add(100.0000001, "Dilantin", "Melanie", DateTime.Now)
        Return table
    End Function
	
End Module

 
Imports System
Imports System.Xml
Imports System.Data
                
Public Module Module1
    Public Sub Main()
        ' Get a DataTable instance from helper function.
        Dim table As DataTable = GetTable()
        
'       Console.WriteLine("Table rows = " & table.Rows.Count)
        
'       For Each row As DataRow In table.Rows
'            ' Write value of first Integer.
'           Console.WriteLine(row(0))
'        Next
    
        Dim sql As String = "Dosage > 0" 
        Dim rows() As DataRow = table.Select(sql)
        
        For Each row As DataRow In rows
            ' Convert and write first value
            row(0) = Convert.ToInt32(row(0))
            Console.WriteLine(row(0))
        Next