在尝试正确格式化某些数据时遇到了一些麻烦。
我不确定LINQ在这种情况下是否有帮助，但以下是：
预期产量
openGL.1.so当前数据输出
March 14
2:00 PM - 7:00 PM | Registration
5:30 PM - 7:00 PM | Meetup
7:30 PM - 9:00 PM | Dinner
March 15
2:00 PM - 7:00 PM | Registration
5:30 PM - 7:00 PM | Meetup
代码结构
March 14
2:00 PM - 7:00 PM | Registration
March 14
5:30 PM - 7:00 PM | Meetup
March 14
7:30 PM - 9:00 PM | Dinner
March 15
2:00 PM - 7:00 PM | Registration
March 15
6:00 PM - 7:00 PM | Meetup
我已经引用了诸如THIS之类的其他SO问题，但是我不确定LINQ是否会使期望的输出更容易获得。
欢迎任何建议。我正在尝试为每个循环添加一个嵌套，然后如果sessionDate相同，则添加一个条件。
****** 更新 *******
我非常感谢您的反馈和有用的答案。我正在尝试对数据进行另一种格式更改。我必须向所有事件项添加特定的SVG图标。 SVG图标特定于“第一”，“最后”，“其余”事件。
我正在尝试使用提供的LINQ答案，但是我对使用它的了解并不深，但是它看起来非常易于阅读。出于本示例的目的，可以将String变量用作first / rest / last的占位符。
我还尝试添加图标，但是我没有使用LINQ。
下面是更新的代码和预期的输出
预期输出
Imports System
Imports System.Globalization
Imports System.Data
Imports System.Data.DataSetExtensions
Public Module Module1
Public Sub Main()
Dim sessions = SampleTable()
Dim ci = CultureInfo.CreateSpecificCulture("en-us")
For Each session In sessions.AsEnumerable()
Dim sessionID = session.Item("SessionID")
Dim sessionDate = CDate(session.Item("SessionStartTime")).ToString("M", ci)
Dim sessionStart = CDate(session.Item("SessionStartTime")).ToString("t", ci)
Dim sessionEnd = CDate(session.Item("SessionEndTime")).ToString("t", ci)
Dim sessionTitle = CStr(session.Item("SessionName"))
Console.WriteLine("{0}", sessionDate)
Console.WriteLine("{0} - {1} | {2}", sessionStart, sessionEnd, sessionTitle)
Next
End Sub
Public Function SampleTable() As DataTable
Dim table As New DataTable
With table
'Add Named Columns
.Columns.Add("SessionID", GetType(Integer))
.Columns.Add("SessionStartTime", GetType(Date))
.Columns.Add("SessionEndTime", GetType(Date))
.Columns.Add("SessionName", GetType(String))
'Add 5 Rows of Data to test
.Rows.Add(1, #03/14/2019 14:00:00#, #03/14/2019 19:00:00#, "Registration")
.Rows.Add(1, #03/14/2019 17:30:00#, #03/14/2019 19:00:00#, "Meetup")
.Rows.Add(1, #03/14/2019 19:30:00#, #03/14/2019 21:00:00#, "Dinner")
.Rows.Add(2, #03/15/2019 14:00:00#, #03/15/2019 19:00:00#, "Registration")
.Rows.Add(2, #03/15/2019 18:00:00#, #03/15/2019 19:00:00#, "Meetup")
End With
Return table
End Function
End Module
代码结构
March 14
(Start SVG) 2:00 PM - 7:00 PM | Registration
(Body SVG) 5:30 PM - 7:00 PM | Meetup
(End SVG) 7:30 PM - 9:00 PM | Dinner
March 15
(Start SVG) 2:00 PM - 7:00 PM | Registration
(End SVG) 5:30 PM - 7:00 PM | Meetup
答案 0 :(得分：2)
使用LINQ时，就像这样
Public Sub Main()
Dim ci = CultureInfo.CreateSpecificCulture("en-us")
Dim sessions = SampleTable().AsEnumerable().[Select](Function(x) New With {
Key .SessionDate = x.Field(Of Date)("SessionStartTime").ToString("M", ci),
Key .SessionStartTime = x.Field(Of Date)("SessionStartTime").ToString("t", ci),
Key .SessionEndTime = x.Field(Of Date)("SessionEndTime").ToString("t", ci),
Key .SessionName = x.Field(Of String)("SessionName")
})
For Each g In sessions.GroupBy(Function(s) s.SessionDate)
Console.WriteLine("{0}", g.Key)
For Each r In g
Console.WriteLine("{0} - {1} | {2}", r.SessionStartTime, r.SessionEndTime, r.SessionName)
Next
Next
End Sub
添加
基本上，您的思维方式没有错。 添加该代码的位置略有不同。 因为您要处理按日期分组的每一行 必须在该循环中完成。
Public Sub Main()
Dim ci = CultureInfo.CreateSpecificCulture("en-us")
Dim sessions = SampleTable().AsEnumerable().[Select](Function(x) New With {
Key .SessionDate = x.Field(Of Date)("SessionStartTime").ToString("M", ci),
Key .SessionStartTime = x.Field(Of Date)("SessionStartTime").ToString("t", ci),
Key .SessionEndTime = x.Field(Of Date)("SessionEndTime").ToString("t", ci),
Key .SessionName = x.Field(Of String)("SessionName")
})
For Each g In sessions.GroupBy(Function(s) s.SessionDate)
Console.WriteLine("{0}", g.Key)
For Each r In g
Dim sessionIcon As String
If r.Equals(g.First) Then
sessionIcon = "<svg>Start Icon</svg>"
ElseIf r.Equals(g.Last) Then
sessionIcon = "<svg>End Icon</svg>"
Else
sessionIcon = "<svg>Body Icon</svg>"
End If
Console.WriteLine("{3} {0} - {1} | {2}", r.SessionStartTime, r.SessionEndTime, r.SessionName, sessionIcon)
Next
Next
End Sub
答案 1 :(得分：1)
如果您不希望花哨的东西，则可能会达到最终结果：
0x0000000000bc724e <+80>: mov rax,QWORD PTR [r8+0x8]
0x0000000000bc7252 <+84>: test al,0x1
0x0000000000bc7254 <+86>: je 0xbc7263 <_ZN24CPDF_StreamContentParser10OnOperatorEPKc+101>
0x0000000000bc7256 <+88>: mov rdx,QWORD PTR [r8+0x10]
0x0000000000bc725a <+92>: mov rdx,QWORD PTR [rdi+rdx*1]
0x0000000000bc725e <+96>: mov rax,QWORD PTR [rdx+rax*1-0x1]
0x0000000000bc7263 <+101>: imul r9,r9,0x18
0x0000000000bc7267 <+105>: lea rdx,[rip+0x180f402] # 0x23d6670 <_ZL9g_OpCodes>
0x0000000000bc726e <+112>: add rdi,QWORD PTR [rdx+r9*1+0x10]
0x0000000000bc7273 <+117>: call rax
答案 2 :(得分：0)
我添加了一个复杂功能，可以按任意顺序输入事件，然后将其分类到DataView中。
Sub Main()
Dim sessions = SampleTable()
Dim SortedView As New DataView(sessions)
SortedView.Sort = "SessionStartTime"
Dim ci = CultureInfo.CreateSpecificCulture("en-us")
Dim row As DataRowView = SortedView(0)
Dim currentDate As String = #1/1/1950#.ToString("YYYY-MM-dd") 'CDate(row("SessionStartTime")).Date
For Each session As DataRowView In SortedView
If currentDate <> CDate(session.Item("SessionStartTime")).ToString("YYYY-MM-dd") Then
Dim sessionDate = CDate(session.Item("SessionStartTime")).ToString("M", ci)
Console.WriteLine("{0}", sessionDate)
currentDate = CDate(session.Item("SessionStartTime")).ToString("YYYY-MM-dd")
End If
Dim sessionID = session.Item("SessionID")
Dim sessionStart = CDate(session.Item("SessionStartTime")).ToString("t", ci)
Dim sessionEnd = CDate(session.Item("SessionEndTime")).ToString("t", ci)
Dim sessionTitle = CStr(session.Item("SessionName"))
Console.WriteLine("{0} - {1} | {2}", sessionStart, sessionEnd, sessionTitle)
Next
Console.ReadLine()
End Sub
Public Function SampleTable() As DataTable
Dim table As New DataTable
With table
'Add Named Columns
.Columns.Add("SessionID", GetType(Integer))
.Columns.Add("SessionStartTime", GetType(Date))
.Columns.Add("SessionEndTime", GetType(Date))
.Columns.Add("SessionName", GetType(String))
.Rows.Add(2, #03/15/2019 18:00:00#, #03/15/2019 19:00:00#, "Meetup")
'Add 5 Rows of Data to test
'Notice that the Events do not have to added in order
.Rows.Add(2, #03/15/2019 18:00:00#, #03/15/2019 19:00:00#, "Meetup")
.Rows.Add(1, #03/14/2019 14:00:00#, #03/14/2019 19:00:00#, "Registration")
.Rows.Add(1, #03/14/2019 17:30:00#, #03/14/2019 19:00:00#, "Meetup")
.Rows.Add(1, #03/14/2019 19:30:00#, #03/14/2019 21:00:00#, "Dinner")
.Rows.Add(2, #03/15/2019 14:00:00#, #03/15/2019 19:00:00#, "Registration")
End With
Return table
End Function
答案 3 :(得分：0)
在演示者类的帮助下可读的LINQ
Public Class Session
Private ReadOnly _ci As CultureInfo
Public ReadOnly Name As String
Public ReadOnly StartTime As Date
Public ReadOnly EndTime As Date
Public Sub New(row As DataRow, CultureInfo ci)
_ci= ci
Name = row.Field(Of String)("SessionName")
StartTime = row.Field(Of Date)("SessionStartTime")
EndTime = row.Field(Of Date)("SessionEndTime")
End Sub
Public Overrides Function ToString() As String
Return $"{StartTime.ToString("t", ci)} - {EndTime.ToString("t", ci)} | {Name}"
End Function
End Class
' Format rows with the key row
Dim sessions = SampleTable()
Dim ci = CultureInfo.CreateSpecificCulture("en-us")
var output =
sessions.AsEnumerable().
Select(Function(row) New Session(row, ci)).
GroupBy(Function(session) session.StartTime.Date).
Aggregate(new StringBuilder(),
Function(builder, day)
builder.AppendLine(day.Key.ToString("M", ci))
day.Aggregate(builder, Function(b, session) b.AppendLine(session))
Return builder
End Function).
ToString()
Console.WriteLine(output)