/// <summary>
        /// 检查输入金额,当检测到小数掉后只能输入2位小数
        /// 当充满12个字符后只能修改小数的值
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void valueTextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            //如果不为空
            if (valueTextBox.Text != string.Empty)
            {
                if (valueTextBox.Text.Contains(‘.‘))
                {

                    if (valueTextBox.Text.Count() == 10)
                    {
                        valueTextBox.MaxLength = valueTextBox.Text.IndexOf(‘.‘) + 3;
                    }
                    else
                    {
                        valueTextBox.MaxLength = valueTextBox.Text.IndexOf(‘.‘) + 3;
                    }
                }
                else
                {
                    //当整数达到9位后自动补全小数位，并移动光标到最后一位
                    if (valueTextBox.Text.Count() == 9)
                    {
                        //valueTextBox.Text += ".00";
                        valueTextBox.MaxLength = 9;
                        valueTextBox.SelectionStart = valueTextBox.Text.Length;
                    }
                }
            }
            else
            {
                //为空就重置金额输入框的最大字符数为12
                valueTextBox.MaxLength = 12;
            }

        }
        /// <summary>
        /// 当整数位为9位且当前输入的是小数点时，设置textbox最大字符数为12，移动光标到最后位置
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void valueTextBox_KeyDown(object sender, KeyRoutedEventArgs e)
        {
            //不知道为什么和默认的小数点的代码不一样，默认为110
            if (e.Key.ToString() == "190")
            {
                if (valueTextBox.Text.Count() == 9)
                {
                    valueTextBox.MaxLength = 12;
                    valueTextBox.SelectionStart = valueTextBox.Text.Length;
                }
            }
        }