文本输入框中只允许某些值

Question

您是否看到程序的用户只能在文本输入框中输入特定数字的可能性？示例：

14785(,00)

14787,50

14790(,00)

所以这个例子大约是2.5步。也可以有其他步骤，例如1.5步。进一步的要求是 1) 德语表示法（, 作为小数点分隔符）和 2) 只有正数。我已经有了。由于这个网格，我不能使用 numeric up-down control 并且模数不适合 double。

Public Class FormMain
    Private Entry As Double = 0R
    Private ReadOnly Deu As New System.Globalization.CultureInfo("de-DE")
    Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
        Dim erfolgreich As Boolean = Double.TryParse(TextBox1.Text, System.Globalization.NumberStyles.Float, Deu, Entry)
        If erfolgreich AndAlso Entry > 0.0 Then
            TextBox1.ForeColor = Color.Green
        Else
            TextBox1.ForeColor = Color.Red
        End If
    End Sub
End Class

Answer 1

我解决了这个问题。我将输入的 Double 值乘以 10.0，然后将其转换为 Long。然后我用Modulo检查除以25L是否有0L的余数

Public Class FormMain
    Private Entry As Double = 0R
    Private ReadOnly Deu As New System.Globalization.CultureInfo("de-DE")
    Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
        Dim erfolgreich As Boolean = Double.TryParse(TextBox1.Text, System.Globalization.NumberStyles.Float, Deu, Entry)
        If erfolgreich AndAlso Entry > 0.0 Then
            Dim Eingabe_als_Long As Long = Convert.ToInt64(Entry * 10.0)
            If Eingabe_als_Long Mod 25L = 0L Then
                TextBox1.ForeColor = Color.Green
            Else
                TextBox1.ForeColor = Color.Red
            End If
        Else
            TextBox1.ForeColor = Color.Red
        End If
    End Sub
End Class

文本输入框中只允许某些值

Only certain values are allowed in the text entry box

vb.net

textbox