VB制作的可以限制输入的文本框

通过继承TextBox，添加了一个ValidText属性，用来获取和设置有效的文本输入

还有一个EditAble属性，决定文本框是否支持退格编辑。

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Public Class MyTextBox
    Inherits System.Windows.Forms.TextBox
    Private m_strValidText As String = "0123456789.+-" & Chr(13).ToString
    Private m_blnEditable As Boolean = True

#Region " Windows 窗体设计器生成的代码 "

    Public Sub New()
        MyBase.New()
        '该调用是 Windows 窗体设计器所必需的。
        InitializeComponent()

        '在 InitializeComponent() 调用之后添加任何初始化

    End Sub

    'UserControl1 重写 dispose 以清理组件列表。
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Windows 窗体设计器所必需的
    Private components As System.ComponentModel.IContainer

    '注意: 以下过程是 Windows 窗体设计器所必需的
    '可以使用 Windows 窗体设计器修改此过程。
    '不要使用代码编辑器修改它。
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        components = New System.ComponentModel.Container
    End Sub

#End Region

    Private Sub MyTextBox_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles MyBase.KeyPress
        Dim strLocalString As String
        If EditAble Then
            strLocalString = m_strValidText & Chr(8).ToString
        Else
            strLocalString = m_strValidText
        End If
        If UCase(strLocalString).IndexOf(UCase(e.KeyChar)) < 0 Then
            e.Handled = True
            Beep()
        Else

        End If
    End Sub
    Public Property ValidText() As String
        Get
            Return m_strValidText
        End Get
        Set(ByVal Value As String)
            m_strValidText = Value
        End Set
    End Property
    Public Property EditAble() As Boolean
        Get
            Return m_blnEditable
        End Get
        Set(ByVal Value As Boolean)
            m_blnEditable = Value
        End Set
    End Property
End Class