如何限制用户只能在 vb.net 的文本框中输入整数 [重复]

Question

当用户想要计算他们的 BMI 时，我如何限制他们，以便他们在程序加载时只能在文本框中输入整数？

如果可能的话，我怎样才能将 BMI 答案转换为小数点后 2 位或 1 位？

代码：

Public Class Form1

    Private Sub btnCalculate_Click(sender As Object, e As EventArgs) Handles btnCalculate.Click

        txtHeight.Text = txtHeight.Text / 100 ' converts txtheight into meter

        lblBMI.Text = txtWeight.Text / txtHeight.Text ^ 2 'BMI is equal to txtweight divided by (txtheight)^2

        'BMI = x KG / (y M * y M)

    End Sub

End Class

这就是设计

我知道这可能很简单，但我对编程还很陌生，谢谢！

Answer 1

参考here.

 Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress

    '97 - 122 = Ascii codes for simple letters
    '65 - 90  = Ascii codes for capital letters
    '48 - 57  = Ascii codes for numbers

    If Asc(e.KeyChar) <> 8 Then
        If Asc(e.KeyChar) < 48 Or Asc(e.KeyChar) > 57 Then
            e.Handled = True
        End If
    End If

End Sub

将数字格式化为小数位：

YourLabel.Text = FormatNumber(YourNumber,N) 'N = Number of Decimal Places