Jason N. Gaylord's Blog

# re: VB.NET's "yield return"

If the function returns IEnumerable(Of String) your return statement (which is the equivalent of yield return "MyReturnValue") would be:

Return New String() {"MyReturnValue"}

Or, instead of String it could be any enumerable type.

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# re: VB.NET's "yield return"

I'm new to .NET technology and came across the code below. However I don't know how to apply the suggestions you above to the following code:

public static IEnumerable<string> ReadLinesFromFile(string filename)

{

   using (StreamReader reader = new StreamReader(filename))

   {

       while (true)

       {

           string s = reader.ReadLine();

           if (s == null)

               break;

           yield return s;

       }

   }

}

********

var products = from line in ReadLinesFromFile(@"c:\import.txt")

              let item = line.Split('\t')

              select new

              {

                  Product = item[0],

                  Quantity = Convert.ToInt32(item[1]),

                  Price = Convert.ToDecimal(item[2]),

                  Total = Convert.ToInt32(item[1]) * Convert.ToDecimal(item[2])

              };GridView1.DataSource = products;

GridView1.DataBind();

*******

Please help in converting C# to VB. Thanks!

# re: VB.NET's "yield return"

Public Shared Function ReadLinesFromFile(ByVal fileName As String) As IEnumerable(Of String)

       Dim stringList As New List(Of String)

       Using reader As StreamReader = New StreamReader(fileName)

           Dim s As String

           While True

               s = reader.ReadLine

               If s Is Nothing Then

                   Exit While

               Else

                   stringList.Add(s)

               End If

           End While

       End Using

       Return stringList

   End Function

# re: VB.NET's "yield return"

That works if you're returning an IEnumerable(Of T), but not if you're returning an IEnumerator(Of T). In that case, return your list but tack on the GetEnumerator() function to the end. i.e. Return myList.GetEnumerator()

# re: VB.NET's "yield return"

isnt that defeating the purpose of "yield return" for lazy evaluating.