自定义针对Product Key处理的TextBox

代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Windows.Controls;
using System.Windows.Input;

namespace DriverEasyWPF.Utils
{
    public class LicenseTextBox : TextBox
    {
        private bool isDelete = false;
        public int BasicLength { get; set; }//每段长度
        public int SumCount { get; set; }//总共几段
        public String SpChar { get; set; }//分隔的符号
        public bool ShowSpCharFirst { get; set; }
        protected override void OnTextChanged(TextChangedEventArgs e)
        {
            base.OnTextChanged(e);

            if (ShowSpCharFirst)
                Do();
            else
                Do2();

        }

        private void Do()
        {
            //SetCaretIndex();
            CheckWhetherDelete();

            InitData();
            /* 
             *   eg:   12345-12345-12345-12345-12345
             */
            if (!isDelete)
            {
                for (int i = 0; i < SumCount - 1; i++)
                {
                    int length = BasicLength * (i + 1);
                    AppendSubtractByLength(length + i);
                    IgnoreInputSubtract(length + (i + 2), SpChar);
                }
                int maxLength = BasicLength * SumCount + (SumCount - 1);
                if (Text.Length >= maxLength || (Text.Length >= SumCount*BasicLength && Text.IndexOf(SpChar)<=0))
                {
                    //Text = Text.Substring(0, maxLength);//旧代码
                    //Regex reg = new Regex("[A-Z0-9]{5}-[A-Z0-9]{5}-[A-Z0-9]{5}-[A-Z0-9]{5}-[A-Z0-9]{5}");
                    //原型是:^([A-Z0-9]{{0}}-){4}[A-Z0-9]{{5}}$
                    String regPattern = "^([A-Z0-9]{"+BasicLength+"}-){"+(SumCount-1)+"}[A-Z0-9]{"+BasicLength+"}$";
                    Regex reg = new Regex(regPattern);
                    if (!reg.IsMatch(Text))
                    {
                        String content = Text.Replace(SpChar, String.Empty);
                        Text = content.Substring(0, BasicLength) + SpChar
                            + content.Substring(BasicLength, BasicLength) + SpChar
                            + content.Substring(BasicLength * 2, BasicLength) + SpChar
                            + content.Substring(BasicLength * 3, BasicLength) + SpChar
                            + content.Substring(BasicLength * 4, BasicLength);
                    }
                    SetCaretIndex();
                }
            }
        }

        private void Do2()
        {
            //SetCaretIndex();
            CheckWhetherDelete();

            InitData();
            /* 
             *   eg:   12345-12345-12345-12345-12345
             */
            if (!isDelete)
            {
                for (int i = 0; i < SumCount - 1; i++)
                {
                    int length = BasicLength * (i + 1);
                    EqualsWithoutSpChar(length + i);
                    EqualsWithSpChar(length + i);
                }

                #region old logic
                /*
                if (Text.Length == 6 && Text[5].ToString().Equals(SpChar))
                    Text = Text;
                if (Text.Length == 6 && !Text[5].ToString().Equals(SpChar))
                {
                    Text = Text.Substring(0, 5) + SpChar + Text.Substring(5);
                    SetCaretIndex();
                }

                if (Text.Length == 12 && Text[11].ToString().Equals(SpChar))
                    Text = Text;
                if (Text.Length == 12 && !Text[11].ToString().Equals(SpChar))
                {
                    Text = Text.Substring(0, 11) + SpChar + Text.Substring(11);
                    SetCaretIndex();
                }

                if (Text.Length == 18 && Text[17].ToString().Equals(SpChar))
                    Text = Text;
                if (Text.Length == 18 && !Text[17].ToString().Equals(SpChar))
                {
                    Text = Text.Substring(0, 17) + SpChar + Text.Substring(17);
                    SetCaretIndex();
                }

                if (Text.Length == 24 && Text[23].ToString().Equals(SpChar))
                    Text = Text;
                if (Text.Length == 24 && !Text[23].ToString().Equals(SpChar))
                {
                    Text = Text.Substring(0, 23) + SpChar + Text.Substring(23);
                    SetCaretIndex();
                }
*/
                #endregion

                int maxLength = BasicLength * SumCount + (SumCount - 1);
                if (Text.Length > maxLength)
                {
                    Text = Text.Substring(0, maxLength);
                    SetCaretIndex();
                }
            }
        }

        private void EqualsWithSpChar(int length)
        {
            if (Text.Length == (length+1) && !Text[length].ToString().Equals(SpChar))
            {
                Text = Text.Substring(0, length) + SpChar + Text.Substring(length);
                SetCaretIndex();
            }
        }

        private void EqualsWithoutSpChar(int length)
        {
            if (Text.Length == (length+1) && Text[length].ToString().Equals(SpChar))
                Text = Text;
        }

        /// <summary>
        /// 默认是 5段，每段5个长度
        /// </summary>
        private void InitData()
        {
            if (BasicLength <= 0)
                BasicLength = 5;

            if (SumCount <= 0)
                SumCount = 5;

            if (String.IsNullOrEmpty(SpChar))
                SpChar = "-";

        }

        private void CheckWhetherDelete()
        {
            if (Keyboard.IsKeyDown(Key.Delete) || Keyboard.IsKeyDown(Key.Back))
                isDelete = true;
            else
                isDelete = false;
        }

        private void SetCaretIndex()
        {
            //this.CaretIndex = Text.Length;
            this.Focus();
            this.SelectionStart = Text.Length;
        }

        private void IgnoreInputSubtract(int length, String subChar)
        {
            if (Text.Length == length && Text[length - 1].ToString() == subChar)
            {
                Text = Text.Substring(0, length - 1);
                SetCaretIndex();
            }
        }

        private void AppendSubtractByLength(int length)
        {
            if (Text.Length == length)
            {
                Text += SpChar;
                SetCaretIndex();
            }
        }


    }
}

使用：

 <!--现在xaml的文件头，添加相应的命名空间-->
 xmlns:model="clr-namespace:LicenseKeyTextBoxDemo.Model"
 
 <!--用法如下-->
 <model:LicenseTextBox Margin="88,220,70,255" BasicLength="5" SumCount="5" SpChar="-" IsMSMode="true"/>

想法：

改进：