C# 数据表 LINQ 动态 row.field<datatype> 需要编码

Question

我有以下代码。数据来自 mysql 服务器。我使用 dataadapater.Fill(datatable) 对象和方法来创建数据表 CDMAData。每次数据范围不同时column.datatype都不一样。我需要能够动态指定数据类型。可能吗？错误发生在 r.Field<int>.

var CarrierCDMAPreResults = from row in CDMAData.AsEnumerable()
    where Dates.Contains(row.Field<DateTime>("DateTime"))
        group row by new { Cascade = row.Field<string>("Cascade"), Sector = row.Field<byte>("Sector"), Carrier = row.Field<byte>("Carrier") } into grp
    select new
    {
        Cascade = grp.Key.Cascade,
        Sector = grp.Key.Sector,                                            
        Carrier = grp.Key.Carrier,
        Attempts = grp.Sum(r => r.Field <int> ("Attempts")),
        Successes = grp.Sum(r => r.Field<int>("Successes")),
        Blocks = grp.Sum(r => r.Field<int>("Blocks")),
        Drops = grp.Sum(r => r.Field<int>("Drops")),
        CDMAPE = grp.Sum(r => r.Field<decimal>("CDMA Primary Erlang"))
    };

Answer 1

好吧，对于您的问题，一个非常简单的答案就是对所有内容都使用 Int64。因为您所有较低的值仍然有效。

但是，如果您的列开始变成小数和字符串，那么您就会遇到问题。

var CarrierCDMAPreResults = from row in CDMAData.AsEnumerable()
    where Dates.Contains(row.Field<DateTime>("DateTime"))
        group row by new { Cascade = row.Field<string>("Cascade"), Sector = row.Field<byte>("Sector"), Carrier = row.Field<byte>("Carrier") } into grp
    select new
    {
        Cascade = grp.Key.Cascade,
        Sector = grp.Key.Sector,                                            
        Carrier = grp.Key.Carrier,
        Attempts = grp.Sum(r => r.Field<Int64> ("Attempts")),
        Successes = grp.Sum(r => r.Field<Int64>("Successes")),
        Blocks = grp.Sum(r => r.Field<Int64>("Blocks")),
        Drops = grp.Sum(r => r.Field<Int64>("Drops")),
        CDMAPE = grp.Sum(r => r.Field<decimal>("CDMA Primary Erlang"))
    };

C# 数据表 LINQ 动态 row.field<datatype> 需要编码

C# Datatable LINQ dynamic row.field<datatype> coded needed

c#

mysql

linq

datatable