字符串扩展方法

字符串扩展方法

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

using System.Text;

public static class StringExtend
{
    public static DateTime ToDatetime(this string str)
    {
        if (string.IsNullOrEmpty(str))
            return DateTime.MinValue;
        else
            return Convert.ToDateTime(str);
    }

    public static DateTime? ToNullableDatetime(this string str)
    {
        if (string.IsNullOrEmpty(str))
            return null;
        else
            return Convert.ToDateTime(str);
    }

    public static int ToInt32(this string str)
    {
        if (string.IsNullOrEmpty(str))
            return int.MinValue;
        else
            return Convert.ToInt16(str);
    }

    public static int? ToInt32(this string str)
    {
        if (string.IsNullOrEmpty(str))
            return null;
        else
            return Convert.ToInt16(str);
    }
    public static string HtmlDecode(this string str)
    {
        StringBuilder sb = new StringBuilder(str);
        sb.Replace("<br />", "\n");
        sb.Replace("\r", "");
        sb.Replace("&nbsp;&nbsp;", "\t");
        sb.Replace("&nbsp;", " ");
        sb.Replace("&#39;", "\'");
        sb.Replace("&quot;", "\"");
        sb.Replace("&gt;", ">");
        sb.Replace("&lt;", "<");
        sb.Replace("&amp;", "&");
        return sb.ToString();
    }

    public static string HtmlEncode(this string str)
    {
        StringBuilder sb = new StringBuilder(str);
        sb.Replace("&", "&amp;");
        sb.Replace("<", "&lt;");
        sb.Replace(">", "&gt;");
        sb.Replace("\"", "&quot;");
        sb.Replace("\'", "&#39;");
        sb.Replace(" ", "&nbsp;");
        sb.Replace("\t", "&nbsp;&nbsp;");
        sb.Replace("\r", "");
        sb.Replace("\n", "<br />");
        return sb.ToString();
    }
}