自写的简单屏蔽特定字符的TextBox和数字TextBox

1.屏蔽特定字符的TextBox

Public Class SpTextBox
    Inherits TextBox
    Protected Overrides Sub OnTextChanged(ByVal e As System.EventArgs)
        Dim selStart As Integer = Me.SelectionStart ’保存初始光标位置，方便之后固定光标位置
        Dim errorWordFlag As Integer = 0 ’标记是否出现过特定字符
        For i As Integer = 0 To Me.SelectionStart - 1

　　　　　　 ’防Access注入，屏蔽各种类型单引号，如果有其他需要可自行添加。
            If Me.Text(i) = "'" Or Me.Text(i) = "＇" Or Me.Text(i) = "’" Then
                Me.Text = Me.Text.Substring(0, i) + Me.Text.Substring(i + 1)
                errorWordFlag = 1
                Exit For
            End If
        Next

　　　　 ’出现过特定字符，调整光标位置
        If errorWordFlag = 1 Then
            Me.SelectionStart = selStart - 1
            Me.Focus()
            Exit Sub
        End If

        MyBase.OnTextChanged(e)
    End Sub
End Class

 

2.数字TextBox

Public Class NumTextBox
    Inherits EESTextBox

    Protected Overrides Sub OnTextChanged(ByVal e As System.EventArgs)

　　　　 Dim selStart As Integer = Me.SelectionStart ’保存初始光标位置，方便之后固定光标位置
        Dim wordFlag = 0 ’标记是否出现过非数字非"."字符

　　　　 ’"."开头的Pass掉

        If Me.Text.StartsWith(".") Then
            Me.Text = Me.Text.Substring(1, Me.Text.Length - 1)
            wordFlag = 1

        ’"."结尾的判断之前是否还有"."
        ElseIf Me.Text.EndsWith(".") Then
            If Me.Text.Length > 0 Then
                For i As Integer = 1 To Me.SelectionStart - 1
                    If Me.Text(i) = "." And Me.Text.Substring(0, i).Contains(".") Then
                        Me.Text = Me.Text.Substring(0, i) + Me.Text.Substring(i + 1)
                        wordFlag = 1
                        Exit For
                    End If
                Next
            End If
        Else

　　　　　　 ’循环扫描是否有非数字和"."的字符
            For i As Integer = 0 To Me.SelectionStart - 1
                If Me.Text(i) <> "1" And Me.Text(i) <> "2" And Me.Text(i) <> "3" And Me.Text(i) <> "4" And Me.Text(i) <> "5" And Me.Text(i) <> "6" And Me.Text(i) <> "7" And Me.Text(i) <> "8" And Me.Text(i) <> "9" And Me.Text(i) <> "0" And Me.Text(i) <> "." Then
                    Me.Text = Me.Text.Substring(0, i) + Me.Text.Substring(i + 1)
                    wordFlag = 1
                    Exit For
                End If
            Next
        End If

　　 　　’如果有过非数字非"."字符，调整光标位置
        If wordFlag = 1 Then
            Me.SelectionStart = selStart - 1
            Me.Focus()
            Exit Sub
        End If

        MyBase.OnTextChanged(e)
    End Sub
End Class

　　目前两种TextBox还不免疫Ctrl+V的攻击（就是用Ctrl+V把非法字符贴过了还有问题），之后再完善。

　　P.S. ：之前发的没注释，不专业了。怕是过一阵自己都看不懂了，补上。