class AllDefectsToSubscribersGrouped
{
static void Main()//使用join...into子句进行分组连接 使用分组连接连接缺陷和订阅
{
var query = from defect in SampleData.AllDefects
join subscription in SampleData.AllSubscriptions
on defect.Project equals subscription.Project
//subscription.Project {Chapter11.Model.NotificationSubscription}
//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)}
into groupedSubscriptions
select new { Defect=defect, Subscriptions=groupedSubscriptions };
//{System.Linq.Enumerable.GroupJoinIterator<Chapter11.Model.Defect,Chapter11.Model.NotificationSubscription,Chapter11.Model.Project,<>f__AnonymousType3<Chapter11.Model.Defect,System.Collections.Generic.IEnumerable<Chapter11.Model.NotificationSubscription>>>}
//groupedSubscriptions {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping}
foreach (var entry in query)
//entry
//{ Defect = { 1: MP3 files crash system (2013/5/1-2013/5/23, Showstopper/Accepted, Tim Trotter -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = { 2: Text is too big (2013/5/3-2013/5/9, Trivial/Closed, Deborah Denton -> n/a)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = { 3: Sky is wrong shade of blue (2013/5/3-2013/5/19, Minor/Fixed, Colin Carton -> Tara Tutu)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = { 4: Can't play files more than 200 bytes long (2013/5/4-2013/5/23, Major/Reopened, Darren Dahlia -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = { 5: Installation is slow (2013/5/6-2013/5/15, Trivial/Fixed, Tim Trotter -> Tim Trotter)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = { 6: DivX is choppy on Pentium 100 (2013/5/7-2013/5/29, Major/Accepted, Mary Malcop -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = { 7: Client acts as virus (2013/5/8-2013/5/10, Showstopper/Closed, Deborah Denton -> n/a)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = { 8: Subtitles only work in Welsh (2013/5/8-2013/5/23, Major/Fixed, Darren Dahlia -> Tim Trotter)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = { 9: Voice recognition is confused by background noise (2013/5/9-2013/5/15, Minor/Closed, Colin Carton -> n/a)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {10: User interface should be more caramelly (2013/5/9-2013/5/9, Trivial/Created, Tim Trotter -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {11: Burning a CD makes the printer catch fire (2013/5/10-2013/5/29, Showstopper/Closed, Mary Malcop -> n/a)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {12: Peer to peer pairing passes parameters poorly (2013/5/10-2013/5/12, Minor/Accepted, Tara Tutu -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {13: Delay when sending message (2013/5/11-2013/5/20, Minor/Fixed, Darren Dahlia -> Tara Tutu)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {14: Volume control needs to go to 11 (2013/5/11-2013/5/11, Minor/Created, Mary Malcop -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {15: Splash screen fades too quickly (2013/5/11-2013/5/15, Minor/Fixed, Colin Carton -> Tara Tutu)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {16: Text box doesn't keep up with fast typing (2013/5/12-2013/5/12, Major/Accepted, Deborah Denton -> Deborah Denton)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {17: Password displayed in plain text (2013/5/12-2013/5/13, Showstopper/Closed, Darren Dahlia -> n/a)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {18: Play button points the wrong way (2013/5/12-2013/5/17, Major/Fixed, Tim Trotter -> Tim Trotter)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {19: Wizard needed for CD burning (2013/5/13-2013/5/20, Minor/Fixed, Colin Carton -> Colin Carton)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {20: Subtitles don't display during fast forward (2013/5/13-2013/5/14, Trivial/Accepted, Mary Malcop -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {21: Memory leak when watching Memento (2013/5/13-2013/5/13, Trivial/Created, Darren Dahlia -> Deborah Denton)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {22: Profile screen shows login count of -1 (2013/5/13-2013/5/20, Major/Accepted, Deborah Denton -> Deborah Denton)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {23: Server crashes under heavy load (3 users) (2013/5/13-2013/5/17, Major/Accepted, Tim Trotter -> Deborah Denton)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {24: Unable to connect to any media server (2013/5/15-2013/5/18, Showstopper/Reopened, Tara Tutu -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {25: UI turns black and white when playing old films (2013/5/15-2013/5/25, Minor/Fixed, Deborah Denton -> Tara Tutu)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {26: Password reset changes passwords for all users (2013/5/16-2013/5/18, Showstopper/Closed, Mary Malcop -> n/a)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {27: Modern music sounds rubbish (2013/5/17-2013/5/17, Trivial/Created, Tim Trotter -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {28: Webcam makes me look bald (2013/5/18-2013/5/27, Showstopper/Fixed, Tim Trotter -> Tim Trotter)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {29: Sound is distorted when speakers are underwater (2013/5/18-2013/5/18, Major/Created, Colin Carton -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {30: Japanese characters don't display properly (2013/5/19-2013/5/23, Major/Accepted, Darren Dahlia -> Deborah Denton)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {31: Video takes 100% of CPU (2013/5/20-2013/5/22, Major/Accepted, Tara Tutu -> Deborah Denton)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {32: DVD Easter eggs unavailable (2013/5/22-2013/5/22, Trivial/Created, Tim Trotter -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {33: Transparency is high for menus to be readable (2013/5/23-2013/5/25, Minor/Accepted, Mary Malcop -> Deborah Denton)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {34: About box is missing version number (2013/5/24-2013/5/29, Minor/Fixed, Colin Carton -> Colin Carton)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {35: Logs record confidential conversations (2013/5/25-2013/5/30, Major/Reopened, Tim Trotter -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {36: Profanity filter is too aggressive (2013/5/27-2013/5/29, Minor/Fixed, Deborah Denton -> Tara Tutu)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {37: Full screen mode fails on dual monitors (2013/5/27-2013/5/27, Minor/Created, Tara Tutu -> Deborah Denton)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {38: Visualization hypnotises pets (2013/5/28-2013/5/29, Minor/Accepted, Colin Carton -> Deborah Denton)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {39: Resizing while typing loses input (2013/5/29-2013/5/29, Trivial/Created, Mary Malcop -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {40: Network is saturated when playing WAV file (2013/5/30-2013/5/31, Minor/Fixed, Tim Trotter -> Tim Trotter)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
//{ Defect = {41: Media library tells user to keep the noise down (2013/5/31-2013/5/31, Major/Created, Tara Tutu -> Darren Dahlia)}, Subscriptions = {System.Linq.Lookup<Chapter11.Model.Project,Chapter11.Model.NotificationSubscription>.Grouping} }
{
Console.WriteLine(entry.Defect.Summary);
foreach (var subscription in entry.Subscriptions)
//var subscription {Chapter11.Model.NotificationSubscription}
{
Console.WriteLine (" {0}", subscription.EmailAddress);
}
}
}
}
分组连接的查询表达式与普通join子句看上去与之类似，不过却具有完全不同的结果。分组连接
结果中的每个元素由左边序列（使用它的原始范围变量）的某个元素和右边序列的所有匹配元素
的序列组成。分组连接用一个新的范围变量表示，变量由join子句中into后面的标识符指定。
显示bug和每个bug所需的通知，但将通知按"每个缺陷"进行分解。
每个条目的Subscriptions属性是一个内嵌序列，该序列包含了匹配该数据项缺陷的所有订阅。
内连接和分组连接之间的一个重要差异（即分组连接和普通分组之间的差异）是，对于分组连接
来说，在左边序列和结果序列之间是一对一的对应关系，即使左边序列中的某些元素在右边序列
中没有任何匹配的元素，也无所谓。这是非常重要的，有时会用于模拟SQL的左外连接。在左边
元素不匹配任何右边元素的时候，嵌入序列就是空的。与内连接一样，分组连接要对右边序列
进行缓冲，而对左边序列进行流处理。
输出
MP3 files crash system
[email protected]
[email protected]
Text is too big
[email protected]
[email protected]
Sky is wrong shade of blue
[email protected]
Can't play files more than 200 bytes long
[email protected]
[email protected]
Installation is slow
[email protected]
[email protected]
DivX is choppy on Pentium 100
[email protected]
[email protected]
Client acts as virus
[email protected]
Subtitles only work in Welsh
[email protected]
[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]
[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]
[email protected]
Splash screen fades too quickly
[email protected]
[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]
[email protected]
Wizard needed for CD burning
[email protected]
[email protected]
Subtitles don't display during fast forward
[email protected]
[email protected]
Memory leak when watching Memento
[email protected]
[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]
[email protected]
UI turns black and white when playing old films
[email protected]
[email protected]
Password reset changes passwords for all users
[email protected]
Modern music sounds rubbish
[email protected]
[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]
[email protected]
DVD Easter eggs unavailable
[email protected]
[email protected]
Transparency is high for menus to be readable
[email protected]
About box is missing version number
[email protected]
[email protected]
Logs record confidential conversations
[email protected]
Profanity filter is too aggressive
[email protected]
Full screen mode fails on dual monitors
[email protected]
[email protected]
Visualization hypnotises pets
[email protected]
[email protected]
Resizing while typing loses input
[email protected]
Network is saturated when playing WAV file
[email protected]
[email protected]
Media library tells user to keep the noise down
[email protected]
[email protected]