如何将DataTable导出为ex​​cel但保留格式

Question

将DataTable转换为excel时出现了2个问题

1. 日期格式很混乱，例如我的原始数据是'2016-12-31'，在excel中变成'31 -12-16'
2. Excel删除尾随零，例如'01'变为'1'

这是代码

MemoryStream result = new MemoryStream();
StreamWriter writer = new StreamWriter(result);

CSVwriter csv = new CSVwriter();
string content = csv.GetFromTable(table);
writer.Write(content);
writer.Flush();

return result;

GetFromTable方法

StringBuilder str = new StringBuilder();
StringBuilder rowstr = new StringBuilder();
string Encloser = "\""

foreach (DataRow row in table.Rows) {
    rowstr.Length = 0;
    foreach (DataColumn col in table.Columns) {
        if (col.Ordinal > 0) {
            rowstr.Append(",");
        }

        object obj = row(table.Columns.IndexOf(col));
        rowstr.Append(Encloser + ToStr(obj) + Encloser);
    }
    if (rowstr.Length > 0) {
        str.AppendLine(rowstr.ToString());
    }
}

return str.ToString();

更新：

str.ToString()结果

"Date","Code"
"2016-01-31","01"
"2016-01-31","02"