如何获取字符串中所有数字的总和-Visual Basic 2010（模块）

耶伦说的是：

    Dim mytext As String = "123a123"
    Dim sum As Integer = 0
    For Each ch As Char In mytext
        Dim i As Integer
        If Integer.TryParse(ch, i) Then
            sum += i
        End If
    Next