做了一个控件.....作用是只可以输入数字.点号和"-"号


     Public Class MyNumerricTextBox'----声明自已的控件类
     Inherits System.Windows.Forms.TextBox'----从textbox继承


     Private Sub MyNumerricTextBox_KeyPress(ByVal sender As Object, ByVal e   As  System.Windows.Forms.KeyPressEventArgs) Handles MyBase.KeyPress
      '--------自定义事件  
        Dim KeyAscii As Integer
        KeyAscii = Asc(e.KeyChar)

        Select Case KeyAscii
            Case 48 To 57
            Case 45
                'If Microsoft.VisualBasic.Strings.InStr(Me.Text) <> 0 Then
                If InStr(Me.Text, "-") <> 0 Then
                    KeyAscii = 0
                End If
            Case 46
                If InStr(Me.Text, ".") <> 0 Then
                    KeyAscii = 0
                End If
            Case Else
                KeyAscii = 0
        End Select
        If KeyAscii = 0 Then
            e.Handled = True
        Else
            e.Handled = False
        End If
    End Sub
End Class