class AllDefectsToSubscribers
{
static void Main() //根据项目把bug和通知订阅连接在一起
{
var query = from defect in SampleData.AllDefects
//query {System.Linq.Enumerable.JoinIterator<Chapter11.Model.Defect,Chapter11.Model.NotificationSubscription,Chapter11.Model.Project,<>f__AnonymousType2<string,string>>}
join subscription in SampleData.AllSubscriptions
//subscription {Chapter11.Model.NotificationSubscription}
on defect.Project equals subscription.Project //看这句会不会执行下一句 select new 能执行就是会打印两条一样Summary不一样的Email
//defect
//{ 1: MP3 files crash system (2013/5/1-2013/5/23, Showstopper/Accepted, Tim Trotter -> Darren Dahlia)}
//defect = { 2: Text is too big(2013/5/3-2013/5/9, Trivial/Closed, Deborah Denton -> n/a)}
//{ 3: Sky is wrong shade of blue (2013/5/3-2013/5/19, Minor/Fixed, Colin Carton -> Tara Tutu)}
//{ 4: Can't play files more than 200 bytes long (2013/5/4-2013/5/23, Major/Reopened, Darren Dahlia -> Darren Dahlia)}
//{ 5: Installation is slow (2013/5/6-2013/5/15, Trivial/Fixed, Tim Trotter -> Tim Trotter)}
//{ 6: DivX is choppy on Pentium 100 (2013/5/7-2013/5/29, Major/Accepted, Mary Malcop -> Darren Dahlia)}
//{ 7: Client acts as virus (2013/5/8-2013/5/10, Showstopper/Closed, Deborah Denton -> n/a)}
//{ 8: Subtitles only work in Welsh(2013/5/8-2013/5/23, Major/Fixed, Darren Dahlia -> Tim Trotter)}
//{ 9: Voice recognition is confused by background noise (2013/5/9-2013/5/15, Minor/Closed, Colin Carton -> n/a)}
//{10: User interface should be more caramelly (2013/5/9-2013/5/9, Trivial/Created, Tim Trotter -> Darren Dahlia)}
//{11: Burning a CD makes the printer catch fire (2013/5/10-2013/5/29, Showstopper/Closed, Mary Malcop -> n/a)}
//{12: Peer to peer pairing passes parameters poorly (2013/5/10-2013/5/12, Minor/Accepted, Tara Tutu -> Darren Dahlia)}
//{13: Delay when sending message (2013/5/11-2013/5/20, Minor/Fixed, Darren Dahlia -> Tara Tutu)}
//{14: Volume control needs to go to 11 (2013/5/11-2013/5/11, Minor/Created, Mary Malcop -> Darren Dahlia)}
//{15: Splash screen fades too quickly (2013/5/11-2013/5/15, Minor/Fixed, Colin Carton -> Tara Tutu)}
//{16: Text box doesn't keep up with fast typing (2013/5/12-2013/5/12, Major/Accepted, Deborah Denton -> Deborah Denton)}
//{17: Password displayed in plain text (2013/5/12-2013/5/13, Showstopper/Closed, Darren Dahlia -> n/a)}
//{18: Play button points the wrong way (2013/5/12-2013/5/17, Major/Fixed, Tim Trotter -> Tim Trotter)}
//{19: Wizard needed for CD burning (2013/5/13-2013/5/20, Minor/Fixed, Colin Carton -> Colin Carton)}
//{20: Subtitles don't display during fast forward (2013/5/13-2013/5/14, Trivial/Accepted, Mary Malcop -> Darren Dahlia)}
//{21: Memory leak when watching Memento (2013/5/13-2013/5/13, Trivial/Created, Darren Dahlia -> Deborah Denton)}
//{22: Profile screen shows login count of -1 (2013/5/13-2013/5/20, Major/Accepted, Deborah Denton -> Deborah Denton)}
//{23: Server crashes under heavy load (3 users) (2013/5/13-2013/5/17, Major/Accepted, Tim Trotter -> Deborah Denton)}
//{24: Unable to connect to any media server (2013/5/15-2013/5/18, Showstopper/Reopened, Tara Tutu -> Darren Dahlia)}
//{25: UI turns black and white when playing old films (2013/5/15-2013/5/25, Minor/Fixed, Deborah Denton -> Tara Tutu)}
//{26: Password reset changes passwords for all users (2013/5/16-2013/5/18, Showstopper/Closed, Mary Malcop -> n/a)}
//{27: Modern music sounds rubbish (2013/5/17-2013/5/17, Trivial/Created, Tim Trotter -> Darren Dahlia)}
//{28: Webcam makes me look bald (2013/5/18-2013/5/27, Showstopper/Fixed, Tim Trotter -> Tim Trotter)}
//{29: Sound is distorted when speakers are underwater (2013/5/18-2013/5/18, Major/Created, Colin Carton -> Darren Dahlia)}
//{30: Japanese characters don't display properly (2013/5/19-2013/5/23, Major/Accepted, Darren Dahlia -> Deborah Denton)}
//{31: Video takes 100% of CPU (2013/5/20-2013/5/22, Major/Accepted, Tara Tutu -> Deborah Denton)}
//{32: DVD Easter eggs unavailable (2013/5/22-2013/5/22, Trivial/Created, Tim Trotter -> Darren Dahlia)}
//{33: Transparency is high for menus to be readable (2013/5/23-2013/5/25, Minor/Accepted, Mary Malcop -> Deborah Denton)}
//{34: About box is missing version number (2013/5/24-2013/5/29, Minor/Fixed, Colin Carton -> Colin Carton)}
//{35: Logs record confidential conversations (2013/5/25-2013/5/30, Major/Reopened, Tim Trotter -> Darren Dahlia)}
//{36: Profanity filter is too aggressive (2013/5/27-2013/5/29, Minor/Fixed, Deborah Denton -> Tara Tutu)}
//{37: Full screen mode fails on dual monitors (2013/5/27-2013/5/27, Minor/Created, Tara Tutu -> Deborah Denton)}
//{38: Visualization hypnotises pets (2013/5/28-2013/5/29, Minor/Accepted, Colin Carton -> Deborah Denton)}
//{39: Resizing while typing loses input (2013/5/29-2013/5/29, Trivial/Created, Mary Malcop -> Darren Dahlia)}
//{40: Network is saturated when playing WAV file (2013/5/30-2013/5/31, Minor/Fixed, Tim Trotter -> Tim Trotter)}
//{41: Media library tells user to keep the noise down (2013/5/31-2013/5/31, Major/Created, Tara Tutu -> Darren Dahlia)}
select new { defect.Summary, subscription.EmailAddress };
foreach (var entry in query)
//var entry { Summary = "MP3 files crash system", EmailAddress = "[email protected]" }
//entry = { Summary = "MP3 files crash system", EmailAddress = "[email protected]" }, query = {System.Linq.Enumerable.JoinIterator<Chapter11.Model.Defect,Chapter11.Model.NotificationSubscription,Chapter11.Model.Project,<>f__AnonymousType2<string,string>>}
// Summary = "Text is too big", EmailAddress = "[email protected]" }
//{ Summary = "Text is too big", EmailAddress = "[email protected]" }
//{ Summary = "Sky is wrong shade of blue", EmailAddress = "[email protected]" }
//{ Summary = "Can't play files more than 200 bytes long", EmailAddress = "[email protected]" }
//{ Summary = "Can't play files more than 200 bytes long", EmailAddress = "[email protected]" }
//{ Summary = "Installation is slow", EmailAddress = "[email protected]" }
//{ Summary = "Installation is slow", EmailAddress = "[email protected]" }
//{ Summary = "DivX is choppy on Pentium 100", EmailAddress = "[email protected]" }
//{ Summary = "DivX is choppy on Pentium 100", EmailAddress = "[email protected]" }
//{ Summary = "Client acts as virus", EmailAddress = "[email protected]" }
//{ Summary = "Subtitles only work in Welsh", EmailAddress = "[email protected]" }
//{ Summary = "Subtitles only work in Welsh", EmailAddress = "[email protected]" }
//{ Summary = "Voice recognition is confused by background noise", EmailAddress = "[email protected]" }
//{ Summary = "User interface should be more caramelly", EmailAddress = "[email protected]" }
//{ Summary = "Burning a CD makes the printer catch fire", EmailAddress = "[email protected]" }
//{ Summary = "Burning a CD makes the printer catch fire", EmailAddress = "[email protected]" }
//{ Summary = "Peer to peer pairing passes parameters poorly", EmailAddress = "[email protected]" }
//{ Summary = "Delay when sending message", EmailAddress = "[email protected]" }
//{ Summary = "Volume control needs to go to 11", EmailAddress = "[email protected]" }
//{ Summary = "Volume control needs to go to 11", EmailAddress = "[email protected]" }
//等等
{
Console.WriteLine("{0}: {1}", entry.EmailAddress, entry.Summary);
}
}
}
显示每个媒体播放器两次，一次显示 [email protected] 一次显示
[email protected],因为老板非常关心媒体播放器项目。
我们容易进行反转连接，调换左右序列的位置。结果包含的条目相同，只是顺序不同。在
LINQ to Objects的实现中，返回条目的顺序为：先返回使用左边序列中第1个元素的所有成对
数据能被返回（按右边序列的顺序），接着返回使用左边序列中的第2个元素的所有成对数据，
依次类推。右边序列被缓冲处理，不过左边序列仍然进行流处理---所以，如果你打算把一个巨大
序列连接到一个极小的序列上，应尽可能把小序列作为右边序列。这种操作仍然是延迟的:在
访问第1个数据对时，它才会开始执行，然后再从某个序列中读取数据。这时，会读取整个右边
序列，来建立一个从键到生成这些键的值的映射。之后，它就不需要再次读取右边的序列了，
这时你可能迭代左边的序列，生成适当的数据对。
输出
[email protected]: MP3 files crash system
[email protected]: MP3 files crash system
[email protected]: Text is too big
[email protected]: Text is too big
[email protected]: Sky is wrong shade of blue
[email protected]: Can't play files more than 200 bytes long
[email protected]: Can't play files more than 200 bytes long
[email protected]: Installation is slow
[email protected]: Installation is slow
[email protected]: DivX is choppy on Pentium 100
[email protected]: DivX is choppy on Pentium 100
[email protected]: Client acts as virus
[email protected]: Subtitles only work in Welsh
[email protected]: Subtitles only work in Welsh
[email protected]: Voice recognition is confused by background noise
[email protected]: User interface should be more caramelly
[email protected]: Burning a CD makes the printer catch fire
[email protected]: Burning a CD makes the printer catch fire
[email protected]: Peer to peer pairing passes parameters poorly
[email protected]: Delay when sending message
[email protected]: Volume control needs to go to 11
[email protected]: Volume control needs to go to 11
[email protected]: Splash screen fades too quickly
[email protected]: Splash screen fades too quickly
[email protected]: Text box doesn't keep up with fast typing
[email protected]: Password displayed in plain text
[email protected]: Play button points the wrong way
[email protected]: Play button points the wrong way
[email protected]: Wizard needed for CD burning
[email protected]: Wizard needed for CD burning
[email protected]: Subtitles don't display during fast forward
[email protected]: Subtitles don't display during fast forward
[email protected]: Memory leak when watching Memento
[email protected]: Memory leak when watching Memento
[email protected]: Profile screen shows login count of -1
[email protected]: Server crashes under heavy load (3 users)
[email protected]: Unable to connect to any media server
[email protected]: Unable to connect to any media server
[email protected]: UI turns black and white when playing old films
[email protected]: UI turns black and white when playing old films
[email protected]: Password reset changes passwords for all users
[email protected]: Modern music sounds rubbish
[email protected]: Modern music sounds rubbish
[email protected]: Webcam makes me look bald
[email protected]: Sound is distorted when speakers are underwater
[email protected]: Japanese characters don't display properly
[email protected]: Video takes 100% of CPU
[email protected]: Video takes 100% of CPU
[email protected]: DVD Easter eggs unavailable
[email protected]: DVD Easter eggs unavailable
[email protected]: Transparency is high for menus to be readable
[email protected]: About box is missing version number
[email protected]: About box is missing version number
[email protected]: Logs record confidential conversations
[email protected]: Profanity filter is too aggressive
[email protected]: Full screen mode fails on dual monitors
[email protected]: Full screen mode fails on dual monitors
[email protected]: Visualization hypnotises pets
[email protected]: Visualization hypnotises pets
[email protected]: Resizing while typing loses input
[email protected]: Network is saturated when playing WAV file
[email protected]: Network is saturated when playing WAV file
[email protected]: Media library tells user to keep the noise down
[email protected]: Media library tells user to keep the noise down