问VBA错误没有为类型'Char‘和’BC30452‘定义整型运算符'Mod’

EN

Private Sub Button3_Click(sender As Object, e As EventArgs)
    Application.Exit()
End Sub

Private Sub Button2_Click(sender As Object, e As EventArgs)
    Textbox1.Text = ""
    Textbox2.Text = ""
End Sub


Private Sub Button1_Click(sender As Object, e As EventArgs)
    Dim sNumber As String
    sNumber = TextBox1.Text

    Textbox2.Text = EvenDigitMessage(sNumber)
End Sub


Private Function IsOnlyNumber(ByVal qty As String) As Boolean
    Dim objRegExp As New System.Text.RegularExpressions.Regex("^\d+$")
    Return objRegExp.Match(qty).Success
End Function

Private Function IsThreeDigitNumber(ByVal num As String) As Boolean
    Dim objRegExp As New System.Text.RegularExpressions.Regex("^\d{3}$")
    Return objRegExp.Match(num).Success
End Function

Private Function EvenDigitMessage(ByVal sNumber As String) As String
    Dim bValidDigits As Boolean
    Dim bValidNumber As Boolean
    Dim sMessage As String
    Dim iTotalEven As Integer = 0

    If Not IsNumeric(sNumber) Then
        sMessage = "Please enter a 3 digit number"
    Else

        bValidNumber = IsOnlyNumber(sNumber)
        bValidDigits = IsThreeDigitNumber(sNumber)

        If bValidNumber = False Or bValidDigits = False Then
            sMessage = "Please enter a 3 digit number"
        Else
            iTotalEven = CountEvenDigits(sNumber)
            sMessage = "This number contains" & iTotalEven & "even digits."
        End If

    End If

    Return sMessage
End Function

Private Function CountEvenDigits(ByVal sNumber As String) As Integer
    Dim i As Integer
    Dim chrArray() As Char
    Dim iTotal As Integer = 0


    chrArray = sNumber.ToCharArray


    For i = 0 To chrArray.Length - 1
        If chrArray(i) Mod 2 = 0 Then
            If iTotal = 0 Then
                iTotal = 1
            Else
                iTotal = iTotal + 1
            End If
        End If
    Next

    Return iTotal
End Function