请问怎样在一个List找到所有字符为 hot的index?

[coyun]

好像可以用findall（Address of Method1），如果我的字符hot是个变量，该怎么弄？谢谢

[Andy__Huang]

string findex="hot"; var list=list.where(t=>t.index.contains(findex)).ToList();

[threenewbee]

Dim s As String = "hot"
Dim query = list.Select(Function(x, i) New With { .x = x, .i = i }).Where(Function(x) x.x = s).Select(Function(x) x.i)
For Each i As Integer In query
    MsgBox i
Next

[coyun]

大家看以下这个例子，要寻找的字符串已经在前面定义好了 Private IDToFind As String = "bk109" 但是，如果我下次要找的是“bl208”，难道我又有事先定义一次？可不可以把这个IDToFind作为一个参数在哪里传递？ Imports System.Collections.Generic Imports System.Linq Imports System.Xml.Linq Module Module1 Private IDToFind As String = "bk109" Public Books As New List(Of Book) Sub Main() FillList() ' Find a book by its ID. Dim result As Book = Books.Find(AddressOf FindID) If result IsNot Nothing Then DisplayResult(result, "Find by ID: " & IDToFind) Else Console.WriteLine(vbCrLf & "Not found: " & IDToFind) End If Console.WriteLine() ' Find last book in collection that has a publish date before 2001. result = Books.FindLast(AddressOf PubBefore2001) If result IsNot Nothing Then DisplayResult(result, "Last book in collection published before 2001:") Else Console.WriteLine(vbCrLf & "Not found: " & IDToFind) End If Console.WriteLine() ' Find all computer books. Dim results As List(Of Book) = Books.FindAll(AddressOf FindComputer) If results.Count <> 0 Then DisplayResults(results, "All computer books:") Else Console.WriteLine(vbCrLf & "No books found.") End If Console.WriteLine() ' Find all books under $10.00. results = Books.FindAll(AddressOf FindUnderTen) If results.Count <> 0 Then DisplayResults(results, "Books under $10:") Else Console.WriteLine(vbCrLf & "No books found.") End If Console.WriteLine() ' Find index values. Console.WriteLine() Dim ndx As Integer = Books.FindIndex(AddressOf FindComputer) Console.WriteLine("Index of first computer book: " & ndx) ndx = Books.FindLastIndex(AddressOf FindComputer) Console.WriteLine("Index of last computer book: " & ndx) Dim mid As Integer = Books.Count / 2 ndx = Books.FindIndex(mid, mid, AddressOf FindComputer) Console.WriteLine("Index of first computer book in the second half of the collection: " & ndx) ndx = Books.FindLastIndex(Books.Count - 1, mid, AddressOf FindComputer) Console.WriteLine("Index of last computer book in the second half of the collection: " & ndx) Console.ReadKey() End Sub Private Sub FillList() ' Create XML elements from a source file. Dim xTree As XElement = XElement.Load("c:\temp\books.xml") ' Create an enumerable collection of the elements. Dim elements As IEnumerable(Of XElement) = xTree.Elements ' Evaluate each element and set values in the book object. For Each el As XElement In elements Dim Book As New Book() Book.ID = el.Attribute("id").Value Dim props As IEnumerable(Of XElement) = el.Elements For Each p As XElement In props If p.Name.ToString.ToLower = "author" Then Book.Author = p.Value End If If p.Name.ToString.ToLower = "title" Then Book.Title = p.Value End If If p.Name.ToString.ToLower = "genre" Then Book.Genre = p.Value End If If p.Name.ToString.ToLower = "price" Then Book.Price = Convert.ToDouble(p.Value) End If If p.Name.ToString.ToLower = "publish_date" Then Book.Publish_date = Convert.ToDateTime(p.Value) End If If p.Name.ToString.ToLower = "description" Then Book.Description = p.Value End If Next Books.Add(Book) Next DisplayResults(Books, "All books:") Console.WriteLine() End Sub ' Predicate delegates for ' Find and FindAll methods. Private Function FindID(ByVal bk As Book) As Boolean If bk.ID = IDToFind Then Return True Else Return False End If End Function Private Function FindComputer(ByVal bk As Book) As Boolean If bk.Genre = "Computer" Then Return True Else Return False End If End Function Private Function FindUnderTen(ByVal bk As Book) As Boolean Dim tendollars As Double = 10.0 If bk.Price < tendollars Then Return True Else Return False End If End Function Private Function PubBefore2001(ByVal bk As Book) As Boolean Dim year2001 As DateTime = New DateTime(2001, 1, 1) Return bk.Publish_date < year2001 End Function Private Sub DisplayResult(ByVal result As Book, ByVal title As String) Console.WriteLine() Console.WriteLine(title) Console.WriteLine(vbLf & result.ID & vbTab & result.Author & _ vbTab & result.Title & vbTab & result.Genre & _ vbTab & result.Publish_date & vbTab & result.Price) Console.WriteLine() End Sub Private Sub DisplayResults(ByVal results As List(Of Book), ByVal title As String) Console.WriteLine() Console.WriteLine(title) For Each b As Book In results Console.Write(vbLf & b.ID & vbTab & b.Author & _ vbTab & b.Title & vbTab & b.Genre & _ vbTab & b.Publish_date & vbTab & b.Price) Next Console.WriteLine() End Sub Public Class Book Public ID As String Public Author As String Public Title As String Public Genre As String Public Price As Double Public Publish_date As DateTime Public Description As String End Class End Module

[coyun]

如果我的要找的字符一致在变呢？比如，要找到所有含hot的index，所有含water的index，以及。。。。怎样把这个做成可以传递的参数形式？

[coyun]

这是一个例子，没人知道吗？

[时光自此有温度]

FindAll该方法是查找list中满足相关条件的项再组成另一个list。而不是查找满足相关条件的项的Index再组成另一个list,楼主没搞清楚情况吧？