这是一种改进的WilPs解答。 我的改进是:

改进了删除和退格键的行为 增加了EmptyValue属性，如果空字符串是不合适的 修正了一些小错别字

/// <summary>
///     Regular expression for Textbox with properties: 
///         <see cref="RegularExpression"/>, 
///         <see cref="MaxLength"/>,
///         <see cref="EmptyValue"/>.
/// </summary>
public class TextBoxInputRegExBehaviour : Behavior<TextBox>
{
    #region DependencyProperties
    public static readonly DependencyProperty RegularExpressionProperty =
        DependencyProperty.Register("RegularExpression", typeof(string), typeof(TextBoxInputRegExBehaviour), new FrameworkPropertyMetadata(".*"));

    public string RegularExpression
    {
        get { return (string)GetValue(RegularExpressionProperty); }
        set { SetValue(RegularExpressionProperty, value); }
    }

    public static readonly DependencyProperty MaxLengthProperty =
        DependencyProperty.Register("MaxLength", typeof(int), typeof(TextBoxInputRegExBehaviour),
                                        new FrameworkPropertyMetadata(int.MinValue));

    public int MaxLength
    {
        get { return (int)GetValue(MaxLengthProperty); }
        set { SetValue(MaxLengthProperty, value); }
    }

    public static readonly DependencyProperty EmptyValueProperty =
        DependencyProperty.Register("EmptyValue", typeof(string), typeof(TextBoxInputRegExBehaviour), null);

    public string EmptyValue
    {
        get { return (string)GetValue(EmptyValueProperty); }
        set { SetValue(EmptyValueProperty, value); }
    }
    #endregion

    /// <summary>
    ///     Attach our behaviour. Add event handlers
    /// </summary>
    protected override void OnAttached()
    {
        base.OnAttached();

        AssociatedObject.PreviewTextInput += PreviewTextInputHandler;
        AssociatedObject.PreviewKeyDown += PreviewKeyDownHandler;
        DataObject.AddPastingHandler(AssociatedObject, PastingHandler);
    }

    /// <summary>
    ///     Deattach our behaviour. remove event handlers
    /// </summary>
    protected override void OnDetaching()
    {
        base.OnDetaching();

        AssociatedObject.PreviewTextInput -= PreviewTextInputHandler;
        AssociatedObject.PreviewKeyDown -= PreviewKeyDownHandler;
        DataObject.RemovePastingHandler(AssociatedObject, PastingHandler);
    }

    #region Event handlers [PRIVATE] --------------------------------------

    void PreviewTextInputHandler(object sender, TextCompositionEventArgs e)
    {
        string text;
        if (this.AssociatedObject.Text.Length < this.AssociatedObject.CaretIndex)
            text = this.AssociatedObject.Text;
        else
        {
            //  Remaining text after removing selected text.
            string remainingTextAfterRemoveSelection;

            text = TreatSelectedText(out remainingTextAfterRemoveSelection)
                ? remainingTextAfterRemoveSelection.Insert(AssociatedObject.SelectionStart, e.Text)
                : AssociatedObject.Text.Insert(this.AssociatedObject.CaretIndex, e.Text);
        }

        e.Handled = !ValidateText(text);
    }

    /// <summary>
    ///     PreviewKeyDown event handler
    /// </summary>
    void PreviewKeyDownHandler(object sender, KeyEventArgs e)
    {
        if (string.IsNullOrEmpty(this.EmptyValue))
            return;

        string text = null;

        // Handle the Backspace key
        if (e.Key == Key.Back)
        {
            if (!this.TreatSelectedText(out text))
            {
                if (AssociatedObject.SelectionStart > 0)
                    text = this.AssociatedObject.Text.Remove(AssociatedObject.SelectionStart - 1, 1);
            }
        }
        // Handle the Delete key
        else if (e.Key == Key.Delete)
        {
            // If text was selected, delete it
            if (!this.TreatSelectedText(out text) && this.AssociatedObject.Text.Length > AssociatedObject.SelectionStart)
            {
                // Otherwise delete next symbol
                text = this.AssociatedObject.Text.Remove(AssociatedObject.SelectionStart, 1);
            }
        }

        if (text == string.Empty)
        {
            this.AssociatedObject.Text = this.EmptyValue;
            if (e.Key == Key.Back)
                AssociatedObject.SelectionStart++;
            e.Handled = true;
        }
    }

    private void PastingHandler(object sender, DataObjectPastingEventArgs e)
    {
        if (e.DataObject.GetDataPresent(DataFormats.Text))
        {
            string text = Convert.ToString(e.DataObject.GetData(DataFormats.Text));

            if (!ValidateText(text))
                e.CancelCommand();
        }
        else
            e.CancelCommand();
    }
    #endregion Event handlers [PRIVATE] -----------------------------------

    #region Auxiliary methods [PRIVATE] -----------------------------------

    /// <summary>
    ///     Validate certain text by our regular expression and text length conditions
    /// </summary>
    /// <param name="text"> Text for validation </param>
    /// <returns> True - valid, False - invalid </returns>
    private bool ValidateText(string text)
    {
        return (new Regex(this.RegularExpression, RegexOptions.IgnoreCase)).IsMatch(text) && (MaxLength == int.MinValue || text.Length <= MaxLength);
    }

    /// <summary>
    ///     Handle text selection
    /// </summary>
    /// <returns>true if the character was successfully removed; otherwise, false. </returns>
    private bool TreatSelectedText(out string text)
    {
        text = null;
        if (AssociatedObject.SelectionLength <= 0) 
            return false;

        var length = this.AssociatedObject.Text.Length;
        if (AssociatedObject.SelectionStart >= length)
            return true;

        if (AssociatedObject.SelectionStart + AssociatedObject.SelectionLength >= length)
            AssociatedObject.SelectionLength = length - AssociatedObject.SelectionStart;

        text = this.AssociatedObject.Text.Remove(AssociatedObject.SelectionStart, AssociatedObject.SelectionLength);
        return true;
    }
    #endregion Auxiliary methods [PRIVATE] --------------------------------
}

用法非常简单:

<i:Interaction.Behaviors>
    <behaviours:TextBoxInputRegExBehaviour RegularExpression="^\d+$" MaxLength="9" EmptyValue="0" />
</i:Interaction.Behaviors>

最好和最优雅的解决方案，只允许整数在文本框(甚至在某些范围)是:

XAML:

<TextBox PreviewTextInput="ValidationTextBox" TextChanged="TextBox_TextChanged"/>

C#:

private void ValidationTextBox(object sender, TextCompositionEventArgs e)
{
    int max = 100;

    //do not allow futher incorrect typing
    e.Handled = !(int.TryParse(((TextBox)sender).Text + e.Text, out int i) && i >= 1 && i <= max);
}

private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
{
    int max = 100;

    if (!int.TryParse(((TextBox)sender).Text, out int j) || j < 1 || j > max)
    {
        //delete incoret input
        ((TextBox)sender).Text = "";
    }
    else
    {
        //delete leading zeros
        ((TextBox)sender).Text = j.ToString();
    }
}

你可以调整最小和最大可接受的数字与max (min)通过开关((TextBox)sender). name。

此解决方案不允许输入的前导零或复制粘贴。在每个场景中，文本框中都有一个正确的数字。

扩展的WPF工具包有一个:NumericUpDown

在Windows窗体中，这很容易;你可以添加一个事件按键和一切工作轻松。然而，在WPF中该事件不存在。但是有一个更简单的方法。

WPF文本框有TextChanged事件，这是一般的一切。它包括粘贴，输入和任何你能想到的东西。

所以你可以这样做:

XAML:

<TextBox name="txtBox1" ... TextChanged="TextBox_TextChanged"/>

背后的代码:

private void TextBox_TextChanged(object sender, TextChangedEventArgs e) {
    string s = Regex.Replace(((TextBox)sender).Text, @"[^\d.]", "");
    ((TextBox)sender).Text = s;
}

这也是可以接受的。，如果你不想要它，只需将它从正则表达式语句中删除为@[^\d]。

注意:此事件可以用于许多TextBox元素，因为它使用发送方对象的文本。您只需编写一次事件，并且可以将其用于多个TextBox元素。

下面是WPF中用于数字输入的库

它具有NumberStyles和regexpattern等用于验证的属性。

WPF文本框的子类

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。