我有一个Datatable，如下所示，我想从其他类中选择重复的名称
Name Class
Akbar 1B
Akbar 1B
Amar 1A
Amar 1C
Antoney 1A
Bindhu 1B
Bindhu 1D
John 1C
Raj 1B
Bindhu 2A
结果应如下
Amar 1A
Amar 1C
Bindhu 1D
Bindhu 1B
Bindhu 2A
提前感谢任何指导
代码
var dtStudents = new DataTable();
dtStudents.Columns.Add("StudentID", typeof(int));
dtStudents.Columns.Add("StudentName", typeof(string));
dtStudents.Columns.Add("Class", typeof(string));
dtStudents.Columns.Add("ContactNo", typeof(string));
DataRow drStudent = dtStudents.NewRow();
drStudent["StudentID"] = 1;
drStudent["StudentName"] = "Akbar";
drStudent["Class"] = "1B";
drStudent["ContactNo"] = "989878679";
dtStudents.Rows.Add(drStudent);
dtStudents.Rows.Add(new object[] { 2, "Akabr", "1B", "989777" });
dtStudents.Rows.Add(new object[] { 3, "Amar", "1A", "3453" });
dtStudents.Rows.Add(new object[] { 4, "Amar", "1C", "543534" });
dtStudents.Rows.Add(new object[] { 5, "Antoney", "1A", "54345" });
dtStudents.Rows.Add(new object[] { 6, "Bindhu", "1B", "53453" });
dtStudents.Rows.Add(new object[] { 7, "Bindhu", "1D", "3453453" });
dtStudents.Rows.Add(new object[] { 8, "John", "1C", "3245345" });
dtStudents.Rows.Add(new object[] { 9, "Bindhu", "2A", "5345345" });
var results =
from d in dtStudents.AsEnumerable()
select d;
dataGridView1.DataSource = results.CopyToDataTable<DataRow>();
答案 0 :(得分：1)
好吧，你没有真正指定你如何连接到你的数据库所以...无论如何，我们假设你有一些IQueryable被叫，我不知道，classes，或者什么的。然后，您可以执行以下操作：
classes
.GroupBy(
x => x.Name,
(key, values) => new { Name = key, Classes = values.Select(x => x.Class).Distinct())
.Where(x => x.Classes.Take(2).Count() == 2)
答案 1 :(得分：1)
var results = dtStudents.AsEnumerable()
.GroupBy(
x => x.Field<string>("StudentName"), // group by student name
(k, xs) => xs.GroupBy(
x1 => x1.Field<string>("Class"), // group by class
(k1, xs1) => xs1.First())) // if there are duplicates, take only the first
.Where(x => x.Count() >= 2) // remove if student only has one class
.SelectMany(x => x); // flatten back to a single collection
dataGridView1.DataSource = results.CopyToDataTable<DataRow>();
答案 2 :(得分：1)
我会这样做：
Public Sub MoveToFolder()
Dim objSelection As Selection
Set objSelection = Application.ActiveExplorer.Selection
Dim iSelected As Integer, iMoved As Integer
iSelected = objSelection.Count 'Get a total for output message
Dim StrOutput As String, StrUnmoved As String, StrName As String
StrUnmoved = "Unmoved Item Count by Sender" & vbNewLine & "============================"
Dim objNS As NameSpace
Dim objParentFolder As Folder, objSubFolder As Folder, objDestFolder As Folder
Dim BFound As Boolean, iLoc As Integer
Set objNS = Application.GetNamespace("MAPI")
Set objParentFolder = objNS.GetDefaultFolder(olFolderInbox)
'Only execute code if the parent folder has subfolders
If objParentFolder.Folders.Count > 0 Then
'Loop through all selected items
For Each Item In objSelection
If Item.Class = 43 Then
'This is an email.
BFound = False
StrName = GetSenderName(Item.SenderName)
For Each objSubFolder In objParentFolder.Folders
If objSubFolder.Folders.Count > 0 Then
On Error Resume Next
Set objDestFolder = Nothing
Set objDestFolder = objSubFolder.Folders(StrName)
On Error GoTo 0
If Not objDestFolder Is Nothing Then
'Folder found.
Item.Move objDestFolder
iMoved = iMoved + 1
BFound = True
Exit For
End If
End If
Next
If Not BFound Then
'Sender folder not found. Check if we have already logged this sender.
iLoc = 0
iLoc = InStr(1, StrUnmoved, StrName)
If iLoc > 0 Then
'Existing sender name. Increment current total.
StrUnmoved = Left(StrUnmoved, iLoc + Len(StrName) + 1) & _
Format(CInt(Mid(StrUnmoved, iLoc + Len(StrName) + 2, 5)) + 1, "00000") & Right(StrUnmoved, Len(StrUnmoved) - iLoc - Len(StrName) - 6)
Else
'New sender name.
StrUnmoved = StrUnmoved & vbNewLine & StrName & ": 00001"
End If
End If
End If
Next
If iMoved = iSelected Then
StrOutput = "All " & iSelected & " items moved to appropriate subfolders."
Else
'Remove extraneous zeroes
StrUnmoved = Replace(StrUnmoved, ": 000", ": ")
StrUnmoved = Replace(StrUnmoved, ": 00", ": ")
StrUnmoved = Replace(StrUnmoved, ": 0", ": ")
StrOutput = iMoved & "/" & iSelected & " items moved to appropriate subfolders; see below for unmoved details." & vbNewLine & vbNewLine & StrUnmoved
End If
MsgBox StrOutput
Else
MsgBox "There are no subfolders to the default inbox. Script will now exit."
End If
End Sub
Function GetSenderName(StrFullSender As String) As String
'Only take action if a non-null string is passed
If Len(StrFullSender) > 1 Then
StrFullSender = Trim(StrFullSender) 'Trim extraneous spaces
Dim StrOutput As String
'Find first case of the end of the name
Dim iChar As Integer
Dim iCommaCount As Integer
Dim iSpaceCount As Integer
For iChar = 1 To Len(StrFullSender)
Select Case Asc(Mid(StrFullSender, iChar, 1))
Case 65 To 90, 97 To 122 '192 to 246, 248 to 255 'Include 192-246 and 248-255 if you will receive emails from senders with accents or other symbols in their names
'No action necessary - this is a letter
Case 45, 151 'Hyphen or EM Dash - could be a hyphenated name
If Mid(StrFullSender, IIf(iChar = 1, 1, iChar - 1), IIf(Len(StrFullSender) - iChar > 1, 3, Len(StrFullSender) - iChar + 1)) <> _
Trim(Mid(StrFullSender, IIf(iChar = 1, 1, iChar - 1), IIf(Len(StrFullSender) - iChar > 1, 3, Len(StrFullSender) - iChar + 1))) Then Exit For
'There is a space on one or both sides of the hyphen. This is a valid stop.
Case 44
iCommaCount = iCommaCount + 1
If iCommaCount > 1 Then Exit For
Case 32
iSpaceCount = iSpaceCount + 1
If iSpaceCount > 1 Then Exit For
Case 39
If Mid(StrFullSender, IIf(iChar = 1, 1, iChar - 1), IIf(Len(StrFullSender) - iChar > 1, 3, Len(StrFullSender) - iChar + 1)) <> _
Trim(Mid(StrFullSender, IIf(iChar = 1, 1, iChar - 1), IIf(Len(StrFullSender) - iChar > 1, 3, Len(StrFullSender) - iChar + 1))) Then Exit For
'There is a space on one or both sides of the apostrophe. This is a valid stop.
Case Else
Exit For
End Select
Next
StrOutput = Trim(Left(StrFullSender, iChar - 1))
GetSenderName = StrOutput
End If
End Function