一个过滤Textbox输入的WPF Behavior

public class TextBoxFilterBehavior : Behavior<TextBox>
    {
        public static readonly DependencyProperty LegalCharsProperty = DependencyProperty.RegisterAttached(
    "LegalChars", typeof(string), typeof(TextBoxFilterBehavior), new PropertyMetadata("1234567890abcdefghijklmnopqrstuvwxyz"));

        public static void SetLegalChars(DependencyObject element, string value)
        {
            element.SetValue(LegalCharsProperty, value);
        }

        public static string GetLegalChars(DependencyObject element)
        {
            return (string)element.GetValue(LegalCharsProperty);
        }

        protected override void OnAttached()
        {
            base.OnAttached();
            AssociatedObject.TextChanged += TextBoxTextChanged;
        }

        protected override void OnDetaching()
        {
            base.OnDetaching();
            AssociatedObject.TextChanged -= TextBoxTextChanged;
        }

        private void FilterLegalChars()
        {
            var cursorLocation = AssociatedObject.SelectionStart;

            for (var i = AssociatedObject.Text.Length - 1; i >= 0; i--)
            {
                var c = AssociatedObject.Text[i];
                var legalChars = GetLegalChars(this);
                if(legalChars.ToCharArray().ToList().Contains(c))
                    continue;
                AssociatedObject.Text = AssociatedObject.Text.Remove(i, 1);
                cursorLocation--;
            }

            AssociatedObject.SelectionStart = Math.Min(AssociatedObject.Text.Length, Math.Max(0, cursorLocation));
        }


        void TextBoxTextChanged(object sender, TextChangedEventArgs e)
        {
            FilterLegalChars();
        }
    }

用法:

            <TextBox x:Name="txtPartNumber" HorizontalAlignment="Left" Height="25">
                <i:Interaction.Behaviors>
                    <Helper:TextBoxFilterBehavior Helper:TextBoxFilterBehavior.LegalChars="1234567890-jJkKsS"/>
                </i:Interaction.Behaviors>
            </TextBox>

只需要在LegalChars的属性里指定所有合法的字符即可.