using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;
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 WpfControlLibrary.NumbericTextbox
{
    /// <summary>
    /// numTextbox.xaml 的交互逻辑
    /// </summary>
    public partial class numTextbox : UserControl
    {
        public numTextbox()
        {
            InitializeComponent();
        }
        // 定义依赖属性
        public static readonly DependencyProperty CustomTextProperty =
        DependencyProperty.Register(
            "CustomText",
            typeof(string),
            typeof(numTextbox),
            new PropertyMetadata(default(string), OnCustomTextChanged)
            
        );

        private static void OnCustomTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var control = d as numTextbox;
            if ( control.Textbox.Text != e.NewValue.ToString() )
            {
                
                control.Textbox.Text = e.NewValue.ToString(); // 同步到控件内部属性
            }            
        }

        // CLR 属性包装器
        public string CustomText
        {
            get { return ( string ) GetValue(CustomTextProperty); }
            set { SetValue(CustomTextProperty, value);  }
        }

        private void TextBox_KeyDown(object sender, KeyEventArgs e)
        {
            TextBox txt = sender as TextBox;

            //屏蔽非法按键
            if ( ( e.Key >= Key.NumPad0 && e.Key <= Key.NumPad9 ) || e.Key == Key.Decimal )
            {
                if ( txt.Text.Contains(".") && e.Key == Key.Decimal )
                {
                    e.Handled = true;
                    return;
                }
                e.Handled = false;
            }
            else if ( ( ( e.Key >= Key.D0 && e.Key <= Key.D9 ) || e.Key == Key.OemPeriod ) && e.KeyboardDevice.Modifiers != ModifierKeys.Shift )
            {
                if ( txt.Text.Contains(".") && e.Key == Key.OemPeriod )
                {
                    e.Handled = true;
                    return;
                }
                e.Handled = false;
            }
            else
            {
                e.Handled = true;
            }
        }

        private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            //屏蔽中文输入和非法字符粘贴输入
            TextBox textBox = sender as TextBox;
            TextChange[] change = new TextChange[e.Changes.Count];
            e.Changes.CopyTo(change, 0);

            int offset = change[0].Offset;
            if ( change[ 0 ].AddedLength > 0 )
            {
                double num = 0;
                if ( !Double.TryParse(textBox.Text, out num) )
                {
                    textBox.Text = textBox.Text.Remove(offset, change[ 0 ].AddedLength);
                    textBox.Select(offset, 0);
                }

            }
            CustomText = textBox.Text;
        }
    }
}