写入数据到CSV

----------------------DownloadCSVAsStreame<T>(IList<T> param, string sheetname = null) where T : new()----------------

基础依据：

 CSV格式为

cell1,cell2,cell3

\r\n

cell1,cell2,cell3

注意：

CSV是用符号分割cell和Row的，所以必须在必要的解决Data中存在于现有字符冲突的其他字符，如英文符号【"】，【,】，【\r】，【\n】，【\t】等

::::RemoveWrap这里RemoveWrap的作用就是去除空字符，和替换敏感字符，以防止CSV导出后布局混乱。

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public static MemoryStream DownloadCSVAsStreame<T>(IList<T> param, string sheetname = null) where T : new()
{
    if (param == null || param.Count < 1)
        return null;
    int rowsCount = param.Count(), columnCount = param.FirstOrDefault().GetType().GetProperties().Count(p => p.PropertyType.IsPublic);
    var tp = typeof(T);
    var tpattr = tp.GetCustomAttribute<JsonObjectAttribute>();
    if (tpattr == null)
        return null;
    StringBuilder sbcsv = new StringBuilder();
    List<PropertyInfo> pts = tp.GetProperties().Where(p => p.PropertyType.IsPublic).Select(o => o).ToList();
    string[] atv = pts.ConvertAll(ii =>
    {
        var jsonPropertyAttribute = ii.GetCustomAttribute<JsonPropertyAttribute>();
        if (jsonPropertyAttribute != null)
            return jsonPropertyAttribute.PropertyName;
        return string.Empty;
    }).ToArray();
    var me = new MemoryStream();
    int paddingrow = 0;
    int rowindex = 0;
    for (int nn = 0; nn < columnCount; nn++)
    {
        if (!string.IsNullOrEmpty(atv[nn]))
        {
            sbcsv.Append(RemoveWrap(atv[nn] ?? pts[nn].Name)).Append(",");
        }
    }
    sbcsv.Remove(sbcsv.Length - 1, 1).Append('\r').Append('\n');
    for (int r = 0; r < rowsCount; r++)
    {
        for (int pj = 0; pj < columnCount; pj++)
        {
            if (!string.IsNullOrEmpty(atv[pj]))
            {
                sbcsv.Append(RemoveWrap(pts[pj].GetValue(param[r]) != null
                        ? pts[pj].GetValue(param[r]).ToString()
                        : "")).Append(",");
            }
        }
        sbcsv.Remove(sbcsv.Length - 1, 1).Append('\r').Append('\n');
    }
    sbcsv.Remove(sbcsv.Length - 2, 2);
    var gbk=Encoding.GetEncoding("GB2312");
    var bts= gbk.GetBytes(sbcsv.ToString().ToArray());
    me.Write(bts,0,bts.Length);
    return me;
}

private static string RemoveWrap(string sb)
{
    return sb.Replace(",", "，").Replace("\r\n", " ").Replace("\r", " ").Replace("\n", " ").Replace("\"","“").Replace("\"", "“");
}