所有下划线替换成文本框并且ID不同

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Text.RegularExpressions;

string sAnswer = "";
string[] Answer = Regex.Split(lbQuestion.Text, "_+", RegexOptions.IgnoreCase);
for (int i = 0; i < (Answer.Count() - 1); i++)
{
if (Answer[0] == "")
{
Answer[0] = "<input type="text" id=txtRightAnswer" + 0 + " style="background-color:#ceedff; border:none; border-bottom:solid 1px black;" />";
}
else if (i == (Answer.Count() - 1) && Answer[(Answer.Count() - 1)] == "")
{
Answer[(Answer.Count() - 1)] = "<input type="text" id=txtRightAnswer" + (Answer.Count() - 1) + " style="background-color:#ceedff; border:none; border-bottom:solid 1px black;" />";
}
else
{
Answer[i] += "<input type="text" id=txtRightAnswer" + i + " style="background-color:#ceedff;border:none; border-bottom:solid 1px black;" />";
}
}
for (int j = 0; j < Answer.Length; j++)
{
sAnswer += Answer[j];
}
Control c = ParseControl(sAnswer);
Panel1.Controls.Clear();
Panel1.Controls.Add(c);