WPF TextBox限制只能输入数字的两种方法

Posted 2021-07-19 dotNET跨平台

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:

<Window x:Class="wpfcore.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:wpfcore" 
        xmlns:controls="http://metro.mahapps.com/winfx/xaml/controls"
        mc:Ignorable="d"
        Background="#2D2D30"
        SnapsToDevicePixels="True"
        FontSize="18"
        UseLayoutRounding="True"
        Title="MainWindow" Width="820" Height="340">
    <StackPanel>
        <!--第一种方法,直接设置禁用输入法，并添加PreviewTextInput事件，如果不满足条件，就禁止输入-->
        <TextBox InputMethod.IsInputMethodEnabled="False" PreviewTextInput="TextBox_PreviewTextInput" Margin="10"/>
        <!--第二种方法,写一个附加属性，在属性改变时，给textbox添加上相应事件，这个写完后，复用时就方便喽-->
        <TextBox local:TextBoxAttachedProperties.IsOnlyNumber="true" Margin="10"/>
    </StackPanel>
</Window>

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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