使用 Linq 從數據表中選擇多行

Question

我有一個包含這些列的DataTable表：

AlertEmail , ClosingDate , OpeningDate , LocationTitle , JobTitle

我想搜索這個DataTable並找到每個 AlertEmail 的記錄。 我這樣做了，但 MailInfo 返回了NULL 。

DataTable dt = amail.GetAllJobAlertForSend();

var AllEmail = dt.AsEnumerable()
                 .Select(row => new {attribute1_name = row.Field<string>("AlertEmail") }).Distinct();

foreach (var mail in AllEmail)
{
    var MailInfo = from p in dt.AsEnumerable()
                   where p.Field<string>("AlertEmail").Trim() == mail.ToString()
                   select new
                   {
                       ClosingDate = p.Field<DateTime>("ClosingDate"),
                       OpeningDate = p.Field<DateTime>("OpeningDate"),
                       LocationTitle = p.Field<string>("LocationTitle"),
                       JobTitle = p.Field<string>("JobTitle")
                   };

    foreach (var info in MailInfo)
    {
        Response.Write(string.Format("{0}", info.ClosingDate));
    }
}

我的代碼有什么問題？

Answer 1

由於郵件是匿名類的對象......訪問其屬性將解決您的問題而不是 ToString

 var MailInfo = from p in dt.AsEnumerable()
                   where p.Field<string>("AlertEmail").Trim() == mail.attribute1_name
                   select new
                   {
                       ClosingDate = p.Field<DateTime>("ClosingDate"),
                       OpeningDate = p.Field<DateTime>("OpeningDate"),
                       LocationTitle = p.Field<string>("LocationTitle"),
                       JobTitle = p.Field<string>("JobTitle")
                   };