gny*_*his 1 .net c# linq asp.net
我正在使用LINQ执行自定义查询,它根据我的语句返回一个匿名类型列表:
var currUnitFaster = (from unit in pacificRepo.Units
join loc in pacificRepo.GeoLocations on new { unit.geo_location.Latitude, unit.geo_location.Longitude } equals new { loc.geo_location.Latitude, loc.geo_location.Longitude }
join st in pacificRepo.UnitStatuses on unit.c_number equals st.c_number
select new {
index = "0",
unit.c_number,
unit.serial_number,
unused = "0",
unit.ip_address,
unit.build_version,
status = (st.status == Pacific.Domain.Entities.UnitStatus.Statuses.COMPLETE) ? "<font color=\"green\">" + st.stage + "</font>" : "<font color=\"red\">" + st.stage + "</font>",
location = (loc==null) ? "Unknown" : loc.city + ", " + loc.state_abbrv,
unit.location_at_address,
latitude = unit.geo_location.Latitude,
longitude = unit.geo_location.Longitude
}).ToList();
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因此,列表中返回的每个元素都是匿名类型:
currUnitFaster[0].ToString() ==> "{ index = 0, c_number = J0000014, serial_number = A2F0JA02, unused = 0, ip_address = 169.254.0.9, build_version = J1, status = <font color=\"green\">Link</font>, location = San Jose, CA, location_at_address = FCC, latitude = 37.390791, longitude = -121.905775 }"
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我想要一个值列表,而不是一个匿名类型列表.这样:
currUnitFaster.First()[0] ==> "0"
currUnitFaster.First()[1] ==> "J0000014"
currUnitFaster.First()[2] ==> "A2F0JA02"
...
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最简单的方法是什么?我知道我可以简单地创建一个列表,然后遍历每个元素currUnitFaster并手动将其添加到该列表中.我想知道是否有一些更清洁的转型或基于铸造的方式来做到这一点.
编辑:我已经采取了塞尔曼的建议select new改为select new object[]. 但是,我现在尝试运行查询时遇到以下异常:
Exception: {"Unable to cast the type 'System.Nullable`1[[System.Double, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]' to type 'System.Object'. LINQ to Entities only supports casting EDM primitive or enumeration types."}
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更改select new 到select new object[]并删除属性名称.
编辑:似乎EF抱怨casts.Try this:
var currUnitFaster = (from unit in pacificRepo.Units
join loc in pacificRepo.GeoLocations on new { unit.geo_location.Latitude, unit.geo_location.Longitude } equals new { loc.geo_location.Latitude, loc.geo_location.Longitude }
join st in pacificRepo.UnitStatuses on unit.c_number equals st.c_number
select new
{
index = "0",
unit.c_number,
unit.serial_number,
unused = "0",
unit.ip_address,
unit.build_version,
status = (st.status == Pacific.Domain.Entities.UnitStatus.Statuses.COMPLETE) ? "<font color=\"green\">" + st.stage + "</font>" : "<font color=\"red\">" + st.stage + "</font>",
location = (loc==null) ? "Unknown" : loc.city + ", " + loc.state_abbrv,
unit.location_at_address,
latitude = unit.geo_location.Latitude,
longitude = unit.geo_location.Longitude
})
.ToList()
.Select(x => new object[] { // write all properties here like x.index, x.c_number });
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