文本框中只能输入数字，一个常见的功能喽，今天就来看看如何实现它~

下面就看看代码

思路都写在xaml里面了，

MainWindow.xaml:

MainWindow.cs:

using System.Text.RegularExpressions;using System.Windows;namespace wpfcore{    public partial class MainWindow : Window    {        public MainWindow()        {            InitializeComponent();            DataContext = this;        }        private void TextBox_PreviewTextInput(object sender, System.Windows.Input.TextCompositionEventArgs e)        {            e.Handled = new Regex("[^0-9]+").IsMatch(e.Text);        }    }}

第二种方法：

新建一个TextBoxAttachedProperties.cs文件，定义附加属性：

using System.Text.RegularExpressions;using System.Windows;using System.Windows.Controls;using System.Windows.Input;namespace wpfcore{    public class TextBoxAttachedProperties    {        public static bool GetIsOnlyNumber(DependencyObject obj)        {            return (bool)obj.GetValue(IsOnlyNumberProperty);        }        public static void SetIsOnlyNumber(DependencyObject obj, bool value)        {            obj.SetValue(IsOnlyNumberProperty, value);        }        public static readonly DependencyProperty IsOnlyNumberProperty =            DependencyProperty.RegisterAttached("IsOnlyNumber", typeof(bool), typeof(TextBox), new PropertyMetadata(false,                (s, e) =>                {                    if (s is TextBox textBox)                    {                        textBox.SetValue(InputMethod.IsInputMethodEnabledProperty, !(bool)e.NewValue);                        textBox.PreviewTextInput -= TxtInput;                        if (!(bool)e.NewValue)                        {                            textBox.PreviewTextInput += TxtInput;                        }                    }                }));        private static void TxtInput(object sender, System.Windows.Input.TextCompositionEventArgs e)        {            e.Handled = new Regex("[^0-9]+").IsMatch(e.Text);        }    }}

ok,结束喽

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