asp.net替换和恢复html特殊字符

/// <summary>
/// 替换html中的特殊字符
/// </summary>
/// <param name="theString">需要进行替换的文本。</param>
/// <returns>替换完的文本。</returns>
public string HtmlEncode（string theString）
{
     theString=theString.Replace（">", ">"）;
     theString=theString.Replace（"<", "<"）;
     theString=theString.Replace（"  ", "  "）;
     theString=theString.Replace（"  ", "  "）;
     theString=theString.Replace（""", """）;
     theString=theString.Replace（""", "'"）;
     theString=theString.Replace（" ", "<br/> "）;
     return theString;
}

/// <summary>
/// 恢复html中的特殊字符
/// </summary>
/// <param name="theString">需要恢复的文本。</param>
/// <returns>恢复好的文本。</returns>
public string HtmlDiscode（string theString）
{
     theString=theString.Replace（">", ">"）;
     theString=theString.Replace（"<", "<"）;
     theString=theString.Replace（" "," "）;
     theString=theString.Replace（"  ","  "）;
     theString=theString.Replace（""","""）;
     theString=theString.Replace（"'","""）;
     theString=theString.Replace（"<br/> "," "）;
     return theString;
}