摘要：
编辑器正在加载…1.oneTT具有字段AABBCC2.twoTT具有字段EEFFBB以连接两个表，Listmul=（from_db.oneTTTjoinbin_db.twoTTTona.BBequalsb.BB其中a.BB！=“”selectnewMulTable｛AAA=a.AA，BBB=a.BB，EEE=b.EE，FFF=b.FF｝）。ToList˂MulTab
编辑器加载中...
1. oneTT有字段AA BB CC
2. twoTT有字段EE FF BB
两个表连接查询，
List<MulTable> mul = (from a in _db.oneTTT
join b in _db.twoTTT
on a.BB equals b.BB
where a.BB != ""
select new MulTable
{
AAA = a.AA,
BBB = a.BB,
EEE = b.EE,
FFF = b.FF
}).ToList<MulTable>();
foreach (MulTable item in mul)
Console.WriteLine(item.AAA + item.BBB + item.EEE);
class MulTable
{
public string AAA = string.Empty;
public string BBB = string.Empty;
public string EEE = string.Empty;
public string FFF = string.Empty;
public override string ToString()
{
return string.Format("AAA: {0}, BBB:{1}, EEE:{2},FFF{3}", AAA, BBB, EEE,FFF);
}
}
string[] Weekdays = { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" };
//see the above code, the IEnumerable<string> WeekdaysWithLength is the explicit object,here var WeekdaysWithLength is implicit object, which will convert by assign type.
// var WeekdaysWithLength = from W in Weekdays where W.Length > 1 orderby W select W;
string[] WeekdaysWithLength = (from W in Weekdays where W.Length > 1 orderby W select W).ToArray<string>();
//listBox1.Items.Clear();
foreach (string str in WeekdaysWithLength)
Console.WriteLine(str);
List<Car> myCars = new List<Car> {
new Car{ Color= "Silver", Make="BMW", PetName="Henry", Speed=100},
new Car{ Color= "Tan", Make="BMW", PetName="Daisy", Speed=90},
new Car{ Color= "Black", Make="VW", PetName="Mary", Speed=55},
new Car{ Color= "Rust", Make="Yugo", PetName="Clunker", Speed=5},
new Car{ Color= "White", Make="Ford", PetName="Melvin", Speed=43}
};
List<Car> fastCars = (from fCar in myCars where fCar.Speed > 55 select fCar).ToList<Car>();
foreach (Car c in fastCars)
Console.WriteLine(c.PetName);
//nongeneric
// non generic collection of Car objects
ArrayList arCars = new ArrayList{
new Car{ Color= "Silver", Make="BMW", PetName="Henry", Speed=100},
new Car{ Color= "Tan", Make="BMW", PetName="Daisy", Speed=90},
new Car{ Color= "Black", Make="VW", PetName="Mary", Speed=55},
new Car{ Color= "Rust", Make="Yugo", PetName="Clunker", Speed=5},
new Car{ Color= "White", Make="Ford", PetName="Melvin", Speed=43}
};
//convert non generic car object collection to enumerable
//IEnumerable<Car> myCars = arCars.OfType<Car>();
//List<Car> fastCars = (from fCar in myCars where fCar.Speed > 55 select fCar).ToList<Car>();
//foreach (Car c in fastCars)
// Console.WriteLine(c.PetName);