我想以某种方式格式化我的文本框，以便用户无法输入任何符号，例如 () , . ; ' " £ $ % ^[]{}
If (Char.IsDigit(e.KeyChar) Or Char.IsControl(e.KeyChar) Or (e.KeyChar = ".")) Then
e.Handled = True
End if
此代码将阻止用户输入数字或整数。但是如何防止符号呢？
提前致谢。
【问题讨论】：
标签： vb.net
怎么样
Not Char.IsLetter(e.KeyChar)
?
【讨论】：
您还可以使用 Ajax 中的“屏蔽编辑”。 Ajax 控制工具包位于：
http://www.asp.net/ajax/ajaxcontroltoolkit/Samples/MaskedEdit/MaskedEdit.aspx
安装 Ajax。按照网站上提供的步骤，了解如何将 AJAX 控件添加到我的 Visual Studio。之后，将“MaskedEditExtender”控件拖到要格式化的文本框中。
在显示“面具”的属性字段中，我输入了 (999) 999-9999
在此之后我发现我必须添加一个名为“TollkitScriptManager”的东西的属性，我相信这个控件必须在您要格式化的文本框上方。
这可能是也可能不是您要查找的内容，但它将允许文本框采用非常特定的格式，并强制用户仅输入数字或您选择的任何内容。这对于在文本框中格式化电话号码非常有用。
【讨论】：
我在previous question 中编写了一个简单的类来执行此操作。这是VB.NET版本的代码：
Public Class TextBoxFilter
<Flags()> Public Enum Filters
None = 0
Text = 1
Numbers = 2
AlphaNumeric = Filters.Text Or Filters.Numbers
Currency = 4
All = Filters.Text Or Filters.Numbers Or Filters.Currency
End Enum
Dim _keyFilter As Dictionary(Of TextBox, Filters)
Dim _allowedKeys As Dictionary(Of TextBox, String)
Dim _invalidKeys As Dictionary(Of TextBox, String)
Dim _keyEventArgs As Dictionary(Of TextBox, Windows.Forms.KeyEventArgs)
Private Shared DecimalMark As String = Application.CurrentCulture.NumberFormat.NumberDecimalSeparator
Private Shared NegativeMark As String = Application.CurrentCulture.NumberFormat.NegativeSign
Private Shared CurrencySymb As String = Application.CurrentCulture.NumberFormat.CurrencySymbol
Private Shared CurrencyDecimal As String = Application.CurrentCulture.NumberFormat.CurrencyDecimalSeparator
Public Sub New()
_keyFilter = New Dictionary(Of TextBox, Filters)
_allowedKeys = New Dictionary(Of TextBox, String)
_invalidKeys = New Dictionary(Of TextBox, String)
_keyEventArgs = New Dictionary(Of TextBox, KeyEventArgs)
End Sub
'set & remove filter'
Public Sub SetTextBoxFilter(ByVal textBox As TextBox, ByVal filter As Filters)
SetTextBoxFilter(textBox, filter, AllowedKeys(textBox), InvalidKeys(textBox))
End Sub
Public Sub SetTextBoxFilter(ByVal textBox As TextBox, ByVal allowedKeys As String)
SetTextBoxFilter(textBox, Filter(textBox), allowedKeys, InvalidKeys(textBox))
End Sub
Public Sub SetTextBoxFilter(ByVal textBox As TextBox, _
ByVal allowedKeys As String, ByVal invalidKeys As String)
SetTextBoxFilter(textBox, Filter(textBox), allowedKeys, invalidKeys)
End Sub
Public Sub SetTextBoxFilter(ByVal textBox As TextBox, ByVal filter As Filters, _
ByVal allowedKeys As String, ByVal invalidKeys As String)
If Not _keyFilter.ContainsKey(textBox) Then
'add the textbox and its filter if it does not exist in '
'the collection of registered textboxes '
_keyFilter.Add(textBox, filter)
_allowedKeys.Add(textBox, allowedKeys)
_invalidKeys.Add(textBox, invalidKeys)
_keyEventArgs.Add(textBox, New System.Windows.Forms.KeyEventArgs(Keys.None))
'add the event handlers '
AddHandler textBox.KeyDown, AddressOf KeyDownUp
AddHandler textBox.KeyUp, AddressOf KeyDownUp
AddHandler textBox.KeyPress, AddressOf KeyPress
AddHandler textBox.Validating, AddressOf Validating
AddHandler textBox.Disposed, AddressOf Disposed
Else
'change the filter of the textbox if it exists in '
'the collection of registered textboxes '
_keyFilter(textBox) = filter
_allowedKeys(textBox) = allowedKeys
_invalidKeys(textBox) = invalidKeys
End If
End Sub
Public Sub RemoveTextBoxFilter(ByVal textBox As TextBox)
If _keyFilter.ContainsKey(textBox) Then
_keyFilter.Remove(textBox)
_allowedKeys.Remove(textBox)
_invalidKeys.Remove(textBox)
_keyEventArgs.Remove(textBox)
RemoveHandler textBox.KeyDown, AddressOf KeyDownUp
RemoveHandler textBox.KeyUp, AddressOf KeyDownUp
RemoveHandler textBox.KeyPress, AddressOf KeyPress
RemoveHandler textBox.Validating, AddressOf Validating
RemoveHandler textBox.Disposed, AddressOf Disposed
End If
End Sub
Public Function ContainsTextBox(ByVal textBox As TextBox) As Boolean
Return _keyFilter.ContainsKey(textBox)
End Function
'properties'
Public Property Filter(ByVal textBox As TextBox) As Filters
Get
If ContainsTextBox(textBox) Then
Return _keyFilter.Item(textBox)
Else
Return Filters.None
End If
End Get
Set(ByVal value As Filters)
SetTextBoxFilter(textBox, value)
End Set
End Property
Public Property AllowedKeys(ByVal textBox As TextBox) As String
Get
If ContainsTextBox(textBox) Then
Return _allowedKeys(textBox)
Else
Return ""
End If
End Get
Set(ByVal value As String)
SetTextBoxFilter(textBox, Me.Filter(textBox), value, Me.InvalidKeys(textBox))
End Set
End Property
Public Property InvalidKeys(ByVal textBox As TextBox) As String
Get
If ContainsTextBox(textBox) Then
Return _invalidKeys(textBox)
Else
Return ""
End If
End Get
Set(ByVal value As String)
SetTextBoxFilter(textBox, Me.Filter(textBox), Me.AllowedKeys(textBox), value)
End Set
End Property
'event handlers'
Private Sub Disposed(ByVal sender As Object, ByVal e As System.EventArgs)
RemoveTextBoxFilter(DirectCast(sender, TextBox))
End Sub
Private Sub KeyDownUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs)
'assign the modifiers'
_keyEventArgs(DirectCast(sender, TextBox)) = e
End Sub
Private Sub KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs)
'ensure key pressed is in the allowed keys'
Dim txt = DirectCast(sender, TextBox)
Dim c = e.KeyChar
Dim allowKey As Boolean = IsValidChar(txt, c, txt.SelectionStart)
'check for backspace & Ctrl combinations if the allowKey is still false'
If allowKey = False Then
If _keyEventArgs(txt).Control Then
'control modifier goes with A, X, C, V and Z for '
'Select All, Cut, Copy, Paste and Undo respectively'
Dim key = _keyEventArgs(txt).KeyCode
allowKey = (key = Keys.A OrElse key = Keys.X OrElse _
key = Keys.C OrElse key = Keys.V OrElse key = Keys.Z)
ElseIf _keyEventArgs(txt).KeyCode = Keys.Back Then
'allow the backspace key'
allowKey = True
End If
End If
'disable the key if it was not valid'
If Not allowKey Then
e.Handled = True
Beep()
End If
End Sub
Private Sub Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs)
Dim box = DirectCast(sender, TextBox)
Dim boxFlags = _keyFilter(box)
'skip validation if the textbox allows all entries or there is no text'
If boxFlags = Filters.All Or box.Text = "" Then Exit Sub
'otherwise check the characters entered'
Dim txtChars = box.Text.ToCharArray
Dim isValidEntry As Boolean = False
'check each caracter for an invalid entry'
For i = 0 To txtChars.Length - 1
Dim c = txtChars(i)
isValidEntry = IsValidChar(box, txtChars(i), i)
If Not isValidEntry Then
box.Select(i, 1)
Exit For
End If
Next
If Not isValidEntry Then e.Cancel = True
If Not isValidEntry Then
MsgBox("The text entered is invalid for the format " & boxFlags.ToString & "." & _
If(_allowedKeys(box) <> "", vbCrLf & "Additional Allowed Keys: " & _allowedKeys(box), "") & _
If(_invalidKeys(box) <> "", vbCrLf & "Additional Invalid Keys: " & _invalidKeys(box), ""), _
MsgBoxStyle.Critical, "Invalid Entry")
End If
End Sub
Private Function IsValidChar(ByVal textBox As TextBox, ByVal c As Char, ByVal charIndex As Integer) As Boolean
'ensure key pressed is in the allowed keys '
Dim pF = _keyFilter(textBox)
Dim aK = _allowedKeys(textBox)
Dim iK = _invalidKeys(textBox)
Dim shouldAllow As Boolean = False
'if filter is set to all, return true unconditionally '
If pF = Filters.All Then Return True
'check preset filters '
'check for text '
If EnumHasFlag(pF, Filters.Text) Then
If Not Char.IsDigit(c) Then
shouldAllow = True
Else
'if the character is a digit, check for the number flag (AlphaNumerics) '
If EnumHasFlag(pF, Filters.Numbers) Then
shouldAllow = True
End If
End If
End If
'check for numbers '
If shouldAllow = False AndAlso EnumHasFlag(pF, Filters.Numbers) Then
If Char.IsDigit(c) Then
shouldAllow = True
ElseIf DecimalMark.Contains(c) Then
'allow the decimal if there is no decimal in the textbox's
'text or the selected text contains the mark'
If Not textBox.Text.Contains(c) OrElse textBox.SelectedText.Contains(c) Then
shouldAllow = True
End If
ElseIf NegativeMark.Contains(c) AndAlso _
(charindex <= NegativeMark.IndexOf(c)) Then
'allow the negative mark if we are at the start of the'
'textbox'
shouldAllow = True
End If
End If
'check for currency '
If shouldAllow = False AndAlso EnumHasFlag(pF, Filters.Currency) Then
If Char.IsDigit(c) Then
shouldAllow = True
ElseIf CurrencyDecimal.Contains(c) Then
'allow the currency decimal mark if it does not exist in the '
'textbox''s text or the selected text contains the mark '
If Not textBox.Text.Substring(0, charIndex).Contains(c) OrElse _
textBox.SelectedText.Contains(c) Then
shouldAllow = True
End If
ElseIf CurrencySymb.Contains(c) AndAlso _
(charIndex <= CurrencySymb.IndexOf(c)) Then
'allow the currency symbol if we are in a valid position'
shouldAllow = True
End If
End If
'now check for extra allowed keys'
If Not shouldAllow Then
shouldAllow = aK.Contains(c)
End If
'and then check for extra invalid keys'
If shouldAllow AndAlso iK.Contains(c) Then
shouldAllow = False
End If
Return shouldAllow
End Function
<System.Diagnostics.DebuggerStepThrough()> _
Private Function EnumHasFlag(ByVal value As [Enum], ByVal flag As [Enum]) As Boolean
Return (Convert.ToInt64(value) And Convert.ToInt64(flag)) = Convert.ToInt64(flag)
End Function
End Class
只需将这个类放在你的项目中，并在你的表单中使用它，如下所示
Public Class Form1
Dim filter = New TextBoxFilter()
Private Sub Form1_Load(object sender, System.EventArgs e) Handles MyBase.Load
filter.SetTextBoxFilter(TextBox1, TextBoxFilter.Filters.Numbers)
End Sub
End Class
【讨论】：
你可以像这样使用模式属性
txtTel.Attributes.Add("placeholder", FormatTel.Libelle)
txtTel.Attributes.Add("title", FormatTel.Libelle)
txtTel.Attributes.Add("pattern", FormatTel.ExprReg)
【讨论】：
我建议使用正则表达式（正则表达式）。您需要做的是检查用户输入的每一个字符。如果字符无效，则必须用有效字符替换它们。 正则表达式模式 "[^!@%&$#()*^\0-9.+-=][_]" 匹配字母字符和空格。上述模式中的符号 ^ 表示不匹配以下任何字符。符号 \ 是一个转义字符， [] 表示字符的匹配范围。如果字符串与上述模式匹配，则必须将用户输入的字符替换为有效字符。
在以下代码中，每次用户输入新字符时，都会检查用户输入是否存在无效字符。
要使代码正常工作，您必须导入以下命名空间：
Imports System.Text.RegularExpressions
windows窗体的完整代码在这里：
Imports System.Text.RegularExpressions
Public Class RegexTest
Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
Dim theText As String = Me.TextBox1.Text
Dim cursor1 As Integer = Me.TextBox1.SelectionStart
Dim cursor2 As Integer = cursor1
Dim finalText As String = ""
If theText IsNot Nothing AndAlso theText.Length >= 1 Then
For x As Integer = 0 To theText.Length - 1 Step +1
Dim Letter As String = theText.Substring(x, 1)
Dim extStr As String = ExtractFirstString(Letter, "[^!@%&\$#\(\)\*\^\\0-9\.\+\-=\]\[_]")
If extStr <> Letter Then
extStr = ""
finalText &= extStr
Else
finalText &= Letter
End If
Next
End If
If finalText <> theText Then
Me.TextBox1.Text = finalText
Me.TextBox1.SelectionStart = cursor2
End If
End Sub
Private Function ExtractFirstString(ByVal sourceStr As String, ByVal pattern As String) As System.String
Dim mc As System.Text.RegularExpressions.MatchCollection
Dim result As String = Nothing
Dim i As Integer
Dim brk As Boolean = False
If sourceStr IsNot Nothing Then
' match email addresses!
mc = Regex.Matches(sourceStr, pattern)
If mc IsNot Nothing Then
Dim results(mc.Count - 1) As String
For i = 0 To results.Length - 1 Step +1
result = mc(i).Value
brk = True
Return result
Exit For 'only return the first match
Next
End If
End If
Return Nothing
End Function
End Class
您必须在表单上创建一个名为 TextBox1 的文本框并处理其 TextChanged evnet。
【讨论】：