VB.NET尝试Catch块问题

Question

我需要完成的程序专注于try catch块。我遇到的问题是每次用户尝试输入任何内容时都会显示错误消息，甚至是有效的数字数据。我一直试图弄清楚过去几个小时，也许有人可以看到我的错误......

Private Sub CalculateButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CalculateButton.Click
    'Convert input values to numeric variables.
    Dim SnowboardInteger, WithBootsInteger, TotalInteger As Integer

    Try
        'Convert snowboard to numeric variable.
        SnowboardInteger = Integer.Parse(SnowboardsTextBox.Text)

        Try
            'Convert with boots if snowboard was sucessful.
            WithBootsInteger = Integer.Parse(WithBootsPriceTextBox.Text)

            'Calculate the total price.
            TotalInteger = SnowboardInteger + WithBootsInteger

            'Calculate summary values.
            SnowboardSumInteger += SnowboardInteger
            WithBootsSumInteger += WithBootsInteger
            TotalSumInteger += TotalSumInteger
            SaleCountInteger += 1
            AverageInteger = TotalSumInteger / SaleCountInteger

            'Format and display price values.
            SnowboardsPriceTextBox.Text = SnowboardInteger.ToString("c")
            WithBootsPriceTextBox.Text = WithBootsInteger.ToString("c")
            TotalPriceTextBox.Text = TotalInteger.ToString("c")

            'Format and display summary values.
            SnowboardRentalTextBox.Text = SnowboardSumInteger.ToString()
            WithBootsRentalTextBox.Text = WithBootsSumInteger.ToString()
            TotalChargesTextBox.Text = TotalSumInteger.ToString()
            AverageChargeTextBox.Text = AverageInteger.ToString()

        Catch Snowboards As FormatException
            'Handle a snowboard exception.
            MessageBox.Show("Snowboards value must be numeric.", "Data Entry Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            With SnowboardsTextBox
                .Focus()
                .SelectAll()
            End With
        End Try

    Catch WithBoots As FormatException
        'Handle a with boots exception.
        MessageBox.Show("Snowboards with Boots value must be numeric.", "Data Entry Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
        With WithBootsTextBox
            .Focus()
            .SelectAll()
        End With

    Catch AnException As Exception
        'Handle any other exceptions.
        MessageBox.Show("Error: " & AnException.Message)
    End Try
End Sub