我希望接受数字和小数点，但没有符号。
我已经看过使用Windows窗体中的NumericUpDown控件的示例，以及来自微软的这个NumericUpDown自定义控件的示例。但到目前为止，似乎NumericUpDown (WPF是否支持)不会提供我想要的功能。我的应用程序是这样设计的，任何头脑正常的人都不会想弄乱箭头。在我的应用程序中，它们没有任何实际意义。
所以我正在寻找一个简单的方法，使一个标准的WPF文本框只接受我想要的字符。这可能吗?实用吗?
当前回答
这里有一个非常简单和容易的方法来做到这一点使用MVVM。
在视图模型中绑定一个整数属性的文本框，这将像宝石一样工作…它甚至会在文本框中输入非整数时显示验证。
XAML代码:
<TextBox x:Name="contactNoTxtBox" Text="{Binding contactNo}" />
查看模型代码:
private long _contactNo;
public long contactNo
{
get { return _contactNo; }
set
{
if (value == _contactNo)
return;
_contactNo = value;
OnPropertyChanged();
}
}
其他回答
我假设:
您希望允许数字输入的文本框的文本属性最初设置为一些有效的数字值(例如，2.7172)。 文本框是主窗口的子窗口 你的主窗口是Window1类 您的文本框名称是numericTB
基本思想:
Add: private string previousText; to your main window class (Window1) Add: previousText = numericTB.Text; to your main window constructor Create a handler for the numericTB.TextChanged event to be something like this: private void numericTB_TextChanged(object sender, TextChangedEventArgs e) { double num = 0; bool success = double.TryParse(((TextBox)sender).Text, out num); if (success & num >= 0) previousText = ((TextBox)sender).Text; else ((TextBox)sender).Text = previousText; }
这将继续设置previousText为numericTB。文本只要它是有效的，并设置numericTB。如果用户写了您不喜欢的内容，则将文本转换到其最后一个有效值。当然，这只是基本的想法，它只是“傻瓜抵抗”，而不是“傻瓜证明”。例如，它不能处理用户乱用空格的情况。所以这里有一个完整的解决方案，我认为是“白痴证明”，如果我错了，请告诉我:
Content of your Window1.xaml file: <Window x:Class="IdiotProofNumericTextBox.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="300" Width="300"> <Grid> <TextBox Height="30" Width="100" Name="numericTB" TextChanged="numericTB_TextChanged"/> </Grid> </Window> Content of your Window.xaml.cs file: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; namespace IdiotProofNumericTextBox { public partial class Window1 : Window { private string previousText; public Window1() { InitializeComponent(); previousText = numericTB.Text; } private void numericTB_TextChanged(object sender, TextChangedEventArgs e) { if (string.IsNullOrEmpty(((TextBox)sender).Text)) previousText = ""; else { double num = 0; bool success = double.TryParse(((TextBox)sender).Text, out num); if (success & num >= 0) { ((TextBox)sender).Text.Trim(); previousText = ((TextBox)sender).Text; } else { ((TextBox)sender).Text = previousText; ((TextBox)sender).SelectionStart = ((TextBox)sender).Text.Length; } } } } }
就是这样。如果你有很多文本框，那么我建议创建一个CustomControl继承从TextBox，所以你可以包装previousText和numericTB_TextChanged在一个单独的文件。
也可以简单地实现一个验证规则，并将其应用到TextBox:
<TextBox>
<TextBox.Text>
<Binding Path="OnyDigitInput" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged">
<Binding.ValidationRules>
<conv:OnlyDigitsValidationRule />
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
实现如下规则(使用与其他答案中建议的相同的Regex):
public class OnlyDigitsValidationRule : ValidationRule
{
public override ValidationResult Validate(object value, CultureInfo cultureInfo)
{
var validationResult = new ValidationResult(true, null);
if(value != null)
{
if (!string.IsNullOrEmpty(value.ToString()))
{
var regex = new Regex("[^0-9.-]+"); //regex that matches disallowed text
var parsingOk = !regex.IsMatch(value.ToString());
if (!parsingOk)
{
validationResult = new ValidationResult(false, "Illegal Characters, Please Enter Numeric Value");
}
}
}
return validationResult;
}
}
在使用这里的一些解决方案一段时间后，我开发了自己的解决方案，该解决方案适用于我的MVVM设置。注意，在允许用户输入错误字符的意义上，它不像其他一些那样动态，但它阻止用户按下按钮，从而阻止他们做任何事情。这很好地配合了我的主题，即当操作无法执行时将按钮变灰。
我有一个文本框，用户必须输入一些文档页面要打印:
<TextBox Text="{Binding NumberPagesToPrint, UpdateSourceTrigger=PropertyChanged}"/>
.．.使用这个绑定属性:
private string _numberPagesToPrint;
public string NumberPagesToPrint
{
get { return _numberPagesToPrint; }
set
{
if (_numberPagesToPrint == value)
{
return;
}
_numberPagesToPrint = value;
OnPropertyChanged("NumberPagesToPrint");
}
}
我还有一个按钮:
<Button Template="{DynamicResource CustomButton_Flat}" Content="Set"
Command="{Binding SetNumberPagesCommand}"/>
.．.使用此命令绑定:
private RelayCommand _setNumberPagesCommand;
public ICommand SetNumberPagesCommand
{
get
{
if (_setNumberPagesCommand == null)
{
int num;
_setNumberPagesCommand = new RelayCommand(param => SetNumberOfPages(),
() => Int32.TryParse(NumberPagesToPrint, out num));
}
return _setNumberPagesCommand;
}
}
然后是SetNumberOfPages()方法，但对于本主题不重要。它在我的案例中工作得很好，因为我不需要向视图的代码隐藏文件中添加任何代码，并且它允许我使用Command属性控制行为。
另一种方法将使用附加的行为，我实现了我的自定义TextBoxHelper类，它可以在我的项目中的所有文本框上使用。因为我认为为此目的订阅每个文本框和每个单独XAML文件中的事件会很耗时。
我实现的TextBoxHelper类有这些特性:
过滤和只接受Double, Int, Uint和自然格式的数字 只过滤和接受偶数或奇数 处理粘贴事件处理程序，以防止将无效文本粘贴到数值文本框中 可以设置一个默认值，这将被用来防止无效的数据作为最后一个镜头订阅的文本框TextChanged事件
下面是TextBoxHelper类的实现:
public static class TextBoxHelper
{
#region Enum Declarations
public enum NumericFormat
{
Double,
Int,
Uint,
Natural
}
public enum EvenOddConstraint
{
All,
OnlyEven,
OnlyOdd
}
#endregion
#region Dependency Properties & CLR Wrappers
public static readonly DependencyProperty OnlyNumericProperty =
DependencyProperty.RegisterAttached("OnlyNumeric", typeof(NumericFormat?), typeof(TextBoxHelper),
new PropertyMetadata(null, DependencyPropertiesChanged));
public static void SetOnlyNumeric(TextBox element, NumericFormat value) =>
element.SetValue(OnlyNumericProperty, value);
public static NumericFormat GetOnlyNumeric(TextBox element) =>
(NumericFormat) element.GetValue(OnlyNumericProperty);
public static readonly DependencyProperty DefaultValueProperty =
DependencyProperty.RegisterAttached("DefaultValue", typeof(string), typeof(TextBoxHelper),
new PropertyMetadata(null, DependencyPropertiesChanged));
public static void SetDefaultValue(TextBox element, string value) =>
element.SetValue(DefaultValueProperty, value);
public static string GetDefaultValue(TextBox element) => (string) element.GetValue(DefaultValueProperty);
public static readonly DependencyProperty EvenOddConstraintProperty =
DependencyProperty.RegisterAttached("EvenOddConstraint", typeof(EvenOddConstraint), typeof(TextBoxHelper),
new PropertyMetadata(EvenOddConstraint.All, DependencyPropertiesChanged));
public static void SetEvenOddConstraint(TextBox element, EvenOddConstraint value) =>
element.SetValue(EvenOddConstraintProperty, value);
public static EvenOddConstraint GetEvenOddConstraint(TextBox element) =>
(EvenOddConstraint)element.GetValue(EvenOddConstraintProperty);
#endregion
#region Dependency Properties Methods
private static void DependencyPropertiesChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (!(d is TextBox textBox))
throw new Exception("Attached property must be used with TextBox.");
switch (e.Property.Name)
{
case "OnlyNumeric":
{
var castedValue = (NumericFormat?) e.NewValue;
if (castedValue.HasValue)
{
textBox.PreviewTextInput += TextBox_PreviewTextInput;
DataObject.AddPastingHandler(textBox, TextBox_PasteEventHandler);
}
else
{
textBox.PreviewTextInput -= TextBox_PreviewTextInput;
DataObject.RemovePastingHandler(textBox, TextBox_PasteEventHandler);
}
break;
}
case "DefaultValue":
{
var castedValue = (string) e.NewValue;
if (castedValue != null)
{
textBox.TextChanged += TextBox_TextChanged;
}
else
{
textBox.TextChanged -= TextBox_TextChanged;
}
break;
}
}
}
#endregion
private static void TextBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
{
var textBox = (TextBox)sender;
string newText;
if (textBox.SelectionLength == 0)
{
newText = textBox.Text.Insert(textBox.SelectionStart, e.Text);
}
else
{
var textAfterDelete = textBox.Text.Remove(textBox.SelectionStart, textBox.SelectionLength);
newText = textAfterDelete.Insert(textBox.SelectionStart, e.Text);
}
var evenOddConstraint = GetEvenOddConstraint(textBox);
switch (GetOnlyNumeric(textBox))
{
case NumericFormat.Double:
{
if (double.TryParse(newText, out double number))
{
switch (evenOddConstraint)
{
case EvenOddConstraint.OnlyEven:
if (number % 2 != 0)
e.Handled = true;
else
e.Handled = false;
break;
case EvenOddConstraint.OnlyOdd:
if (number % 2 == 0)
e.Handled = true;
else
e.Handled = false;
break;
}
}
else
e.Handled = true;
break;
}
case NumericFormat.Int:
{
if (int.TryParse(newText, out int number))
{
switch (evenOddConstraint)
{
case EvenOddConstraint.OnlyEven:
if (number % 2 != 0)
e.Handled = true;
else
e.Handled = false;
break;
case EvenOddConstraint.OnlyOdd:
if (number % 2 == 0)
e.Handled = true;
else
e.Handled = false;
break;
}
}
else
e.Handled = true;
break;
}
case NumericFormat.Uint:
{
if (uint.TryParse(newText, out uint number))
{
switch (evenOddConstraint)
{
case EvenOddConstraint.OnlyEven:
if (number % 2 != 0)
e.Handled = true;
else
e.Handled = false;
break;
case EvenOddConstraint.OnlyOdd:
if (number % 2 == 0)
e.Handled = true;
else
e.Handled = false;
break;
}
}
else
e.Handled = true;
break;
}
case NumericFormat.Natural:
{
if (uint.TryParse(newText, out uint number))
{
if (number == 0)
e.Handled = true;
else
{
switch (evenOddConstraint)
{
case EvenOddConstraint.OnlyEven:
if (number % 2 != 0)
e.Handled = true;
else
e.Handled = false;
break;
case EvenOddConstraint.OnlyOdd:
if (number % 2 == 0)
e.Handled = true;
else
e.Handled = false;
break;
}
}
}
else
e.Handled = true;
break;
}
}
}
private static void TextBox_PasteEventHandler(object sender, DataObjectPastingEventArgs e)
{
var textBox = (TextBox)sender;
if (e.DataObject.GetDataPresent(typeof(string)))
{
var clipboardText = (string) e.DataObject.GetData(typeof(string));
var newText = textBox.Text.Insert(textBox.SelectionStart, clipboardText);
var evenOddConstraint = GetEvenOddConstraint(textBox);
switch (GetOnlyNumeric(textBox))
{
case NumericFormat.Double:
{
if (double.TryParse(newText, out double number))
{
switch (evenOddConstraint)
{
case EvenOddConstraint.OnlyEven:
if (number % 2 != 0)
e.CancelCommand();
break;
case EvenOddConstraint.OnlyOdd:
if (number % 2 == 0)
e.CancelCommand();
break;
}
}
else
e.CancelCommand();
break;
}
case NumericFormat.Int:
{
if (int.TryParse(newText, out int number))
{
switch (evenOddConstraint)
{
case EvenOddConstraint.OnlyEven:
if (number % 2 != 0)
e.CancelCommand();
break;
case EvenOddConstraint.OnlyOdd:
if (number % 2 == 0)
e.CancelCommand();
break;
}
}
else
e.CancelCommand();
break;
}
case NumericFormat.Uint:
{
if (uint.TryParse(newText, out uint number))
{
switch (evenOddConstraint)
{
case EvenOddConstraint.OnlyEven:
if (number % 2 != 0)
e.CancelCommand();
break;
case EvenOddConstraint.OnlyOdd:
if (number % 2 == 0)
e.CancelCommand();
break;
}
}
else
e.CancelCommand();
break;
}
case NumericFormat.Natural:
{
if (uint.TryParse(newText, out uint number))
{
if (number == 0)
e.CancelCommand();
else
{
switch (evenOddConstraint)
{
case EvenOddConstraint.OnlyEven:
if (number % 2 != 0)
e.CancelCommand();
break;
case EvenOddConstraint.OnlyOdd:
if (number % 2 == 0)
e.CancelCommand();
break;
}
}
}
else
{
e.CancelCommand();
}
break;
}
}
}
else
{
e.CancelCommand();
}
}
private static void TextBox_TextChanged(object sender, TextChangedEventArgs e)
{
var textBox = (TextBox)sender;
var defaultValue = GetDefaultValue(textBox);
var evenOddConstraint = GetEvenOddConstraint(textBox);
switch (GetOnlyNumeric(textBox))
{
case NumericFormat.Double:
{
if (double.TryParse(textBox.Text, out double number))
{
switch (evenOddConstraint)
{
case EvenOddConstraint.OnlyEven:
if (number % 2 != 0)
textBox.Text = defaultValue;
break;
case EvenOddConstraint.OnlyOdd:
if (number % 2 == 0)
textBox.Text = defaultValue;
break;
}
}
else
textBox.Text = defaultValue;
break;
}
case NumericFormat.Int:
{
if (int.TryParse(textBox.Text, out int number))
{
switch (evenOddConstraint)
{
case EvenOddConstraint.OnlyEven:
if (number % 2 != 0)
textBox.Text = defaultValue;
break;
case EvenOddConstraint.OnlyOdd:
if (number % 2 == 0)
textBox.Text = defaultValue;
break;
}
}
else
textBox.Text = defaultValue;
break;
}
case NumericFormat.Uint:
{
if (uint.TryParse(textBox.Text, out uint number))
{
switch (evenOddConstraint)
{
case EvenOddConstraint.OnlyEven:
if (number % 2 != 0)
textBox.Text = defaultValue;
break;
case EvenOddConstraint.OnlyOdd:
if (number % 2 == 0)
textBox.Text = defaultValue;
break;
}
}
else
textBox.Text = defaultValue;
break;
}
case NumericFormat.Natural:
{
if (uint.TryParse(textBox.Text, out uint number))
{
if(number == 0)
textBox.Text = defaultValue;
else
{
switch (evenOddConstraint)
{
case EvenOddConstraint.OnlyEven:
if (number % 2 != 0)
textBox.Text = defaultValue;
break;
case EvenOddConstraint.OnlyOdd:
if (number % 2 == 0)
textBox.Text = defaultValue;
break;
}
}
}
else
{
textBox.Text = defaultValue;
}
break;
}
}
}
}
下面是一些简单用法的例子:
<TextBox viewHelpers:TextBoxHelper.OnlyNumeric="Double"
viewHelpers:TextBoxHelper.DefaultValue="1"/>
Or
<TextBox viewHelpers:TextBoxHelper.OnlyNumeric="Natural"
viewHelpers:TextBoxHelper.DefaultValue="3"
viewHelpers:TextBoxHelper.EvenOddConstraint="OnlyOdd"/>
注意，我的TextBoxHelper驻留在viewHelpers xmlns别名中。
我希望这个实现可以减轻其他人的工作:)
事件处理程序正在预览文本输入。在这里，正则表达式只在文本输入不是数字时才匹配文本输入，然后它就不会进入文本框。
如果只需要字母，则将正则表达式替换为[^a-zA-Z]。
XAML
<TextBox Name="NumberTextBox" PreviewTextInput="NumberValidationTextBox"/>
XAML.CS文件
using System.Text.RegularExpressions;
private void NumberValidationTextBox(object sender, TextCompositionEventArgs e)
{
Regex regex = new Regex("[^0-9]+");
e.Handled = regex.IsMatch(e.Text);
}
