Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        MsgBox(getAsciiSum(TextBox1.Text.Substring(0, 5)))
    End Sub
 
    Function getAsciiSum(ByVal s As String) As Integer
        Dim sum As Integer
        For Each c As Char In s
            sum = sum + Asc(c)
        Next
        Return sum
    End Function