List<T>.FindLastIndex 方法

參考

定義

命名空間:: System.Collections.Generic

組件:: System.Collections.dll

組件:: mscorlib.dll

組件:: netstandard.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

搜尋符合指定之述詞所定義的條件之項目，並傳回 List<T> 中或其中一部分中最後一次出現之以零為起始的索引。

多載

FindLastIndex(Predicate<T>)	搜尋符合指定之述詞所定義的條件之項目，並傳回整個 List<T> 內最後一次出現之以為零起始的索引。
FindLastIndex(Int32, Predicate<T>)	搜尋符合指定之述詞所定義的條件之項目，並傳回 List<T> 中從第一個項目延伸到指定之索引的項目範圍內，最後一個符合項目之以零為起始的索引。
FindLastIndex(Int32, Int32, Predicate<T>)	搜尋符合指定之述詞所定義的條件之項目，並傳回 List<T> 中包含指定之項目數目，且結束於指定之索引的項目範圍內最後一個符合項目之以零為起始的索引。

FindLastIndex(Predicate<T>)

來源:: List.cs

來源:: List.cs

來源:: List.cs

搜尋符合指定之述詞所定義的條件之項目，並傳回整個 List<T> 內最後一次出現之以為零起始的索引。

public:
 int FindLastIndex(Predicate<T> ^ match);

public int FindLastIndex (Predicate<T> match);

member this.FindLastIndex : Predicate<'T> -> int

Public Function FindLastIndex (match As Predicate(Of T)) As Integer

參數

match: Predicate<T>

定義要搜尋項目之條件的 Predicate<T> 委派。

傳回

Int32

符合 match 所定義條件的元素，最後一次出現項目之以零為起始的索引 (若有找到)，否則為 -1。

例外狀況

ArgumentNullException

match 為 null。

範例

下列範例示範類別的 List<T> find 方法。類別的List<T>範例包含 book 類別的物件Book，使用範例 XML 檔案中的數據：書籍 (LINQ to XML) 。範例FillList中的方法會使用 LINQ to XML，將 XML 中的值剖析為對象的屬性值book。

下表描述為尋找方法提供的範例。

方法	範例
Find(Predicate<T>)	使用 `IDToFind` 述詞委派依標識符尋找書籍。 C# 範例使用匿名委派。
FindAll(Predicate<T>)	使用述詞委派尋找其 `Genre` 屬性為「Computer」 `FindComputer` 的所有書籍。
FindLast(Predicate<T>)	使用 `PubBefore2001` 述詞委派，尋找在 2001 年之前具有發行日期之集合中的最後一本書。 C# 範例使用匿名委派。
FindIndex(Predicate<T>)	使用述詞委派尋找第一部計算機書籍的 `FindComputer` 索引。
FindLastIndex(Predicate<T>)	使用述詞委派尋找最後一部計算機書籍的 `FindComputer` 索引。
FindIndex(Int32, Int32, Predicate<T>)	使用 `FindComputer` 述詞委派，在集合的第二半尋找第一部計算機書籍的索引。
FindLastIndex(Int32, Int32, Predicate<T>)	使用 `FindComputer` 述詞委派，在集合的第二半尋找最後一部計算機書籍的索引。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;

namespace Find
{
    class Program
    {
        private static string IDtoFind = "bk109";

        private static List<Book> Books = new List<Book>();
        public static void Main(string[] args)
        {
            FillList();

            // Find a book by its ID.
            Book result = Books.Find(
            delegate(Book bk)
            {
                return bk.ID == IDtoFind;
            }
            );
            if (result != null)
            {
                DisplayResult(result, "Find by ID: " + IDtoFind);
            }
            else
            {
                Console.WriteLine("\nNot found: {0}", IDtoFind);
            }

            // Find last book in collection published before 2001.
            result = Books.FindLast(
            delegate(Book bk)
            {
                DateTime year2001 = new DateTime(2001,01,01);
                return bk.Publish_date < year2001;
            });
            if (result != null)
            {
                DisplayResult(result, "Last book in collection published before 2001:");
            }
            else
            {
                Console.WriteLine("\nNot found: {0}", IDtoFind);
            }

            // Find all computer books.
            List<Book> results = Books.FindAll(FindComputer);
            if (results.Count != 0)
            {
                DisplayResults(results, "All computer:");
            }
            else
            {
                Console.WriteLine("\nNo books found.");
            }

            // Find all books under $10.00.
            results = Books.FindAll(
            delegate(Book bk)
            {
                return bk.Price < 10.00;
            }
            );
            if (results.Count != 0)
            {
                DisplayResults(results, "Books under $10:");
            }
            else
            {
                Console.WriteLine("\nNo books found.");
            }

            // Find index values.
            Console.WriteLine();
            int ndx = Books.FindIndex(FindComputer);
            Console.WriteLine("Index of first computer book: {0}", ndx);
            ndx = Books.FindLastIndex(FindComputer);
            Console.WriteLine("Index of last computer book: {0}", ndx);

            int mid = Books.Count / 2;
            ndx = Books.FindIndex(mid, mid, FindComputer);
            Console.WriteLine("Index of first computer book in the second half of the collection: {0}", ndx);

            ndx = Books.FindLastIndex(Books.Count - 1, mid, FindComputer);
            Console.WriteLine("Index of last computer book in the second half of the collection: {0}", ndx);
        }

        // Populates the list with sample data.
        private static void FillList()
        {

            // Create XML elements from a source file.
            XElement xTree = XElement.Load(@"c:\temp\books.xml");

            // Create an enumerable collection of the elements.
            IEnumerable<XElement> elements = xTree.Elements();

            // Evaluate each element and set set values in the book object.
            foreach (XElement el in elements)
            {
                Book book = new Book();
                book.ID = el.Attribute("id").Value;
                IEnumerable<XElement> props = el.Elements();
                foreach (XElement p in props)
                {

                    if (p.Name.ToString().ToLower() == "author")
                    {
                        book.Author = p.Value;
                    }
                    else if (p.Name.ToString().ToLower() == "title")
                    {
                        book.Title = p.Value;
                    }
                    else if (p.Name.ToString().ToLower() == "genre")
                    {
                        book.Genre = p.Value;
                    }
                    else if (p.Name.ToString().ToLower() == "price")
                    {
                        book.Price = Convert.ToDouble(p.Value);
                    }
                    else if (p.Name.ToString().ToLower() == "publish_date")
                    {
                        book.Publish_date = Convert.ToDateTime(p.Value);
                    }
                    else if (p.Name.ToString().ToLower() == "description")
                    {
                        book.Description = p.Value;
                    }
                }

                Books.Add(book);
            }

            DisplayResults(Books, "All books:");
        }

        // Explicit predicate delegate.
        private static bool FindComputer(Book bk)
        {

            if (bk.Genre == "Computer")
            {
                return true;
            }
        else
            {
                return false;
            }
        }

        private static void DisplayResult(Book result, string title)
        {
            Console.WriteLine();
            Console.WriteLine(title);
            Console.WriteLine("\n{0}\t{1}\t{2}\t{3}\t{4}\t{5}", result.ID,
                result.Author, result.Title, result.Genre, result.Price,
                result.Publish_date.ToShortDateString());
            Console.WriteLine();
        }

        private static void DisplayResults(List<Book> results, string title)
        {
            Console.WriteLine();
            Console.WriteLine(title);
            foreach (Book b in results)
            {

                Console.Write("\n{0}\t{1}\t{2}\t{3}\t{4}\t{5}", b.ID,
                    b.Author, b.Title, b.Genre, b.Price,
                    b.Publish_date.ToShortDateString());
            }
            Console.WriteLine();
        }
    }

    public class Book
    {
        public string ID { get; set; }
        public string Author { get; set; }
        public string Title { get; set; }
        public string Genre { get; set; }
        public double Price { get; set; }
        public DateTime Publish_date { get; set; }
        public string Description { get; set; }
    }
}

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)


    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

備註

會 List<T> 從最後一個項目開始向後搜尋，並在第一個元素結束。

Predicate<T>是方法的委派，如果傳遞給它的物件符合委派中定義的條件，則會傳回 true 。目前 List<T> 的專案會個別傳遞至 Predicate<T> 委派。

這個方法會執行線性搜尋;因此，這個方法是 o (n) 運算，其中 n 是 Count。

另請參閱

適用於

FindLastIndex(Int32, Predicate<T>)

來源:: List.cs

來源:: List.cs

來源:: List.cs

搜尋符合指定之述詞所定義的條件之項目，並傳回 List<T> 中從第一個項目延伸到指定之索引的項目範圍內，最後一個符合項目之以零為起始的索引。

public:
 int FindLastIndex(int startIndex, Predicate<T> ^ match);

public int FindLastIndex (int startIndex, Predicate<T> match);

member this.FindLastIndex : int * Predicate<'T> -> int

Public Function FindLastIndex (startIndex As Integer, match As Predicate(Of T)) As Integer

參數

startIndex: Int32

向後搜尋之以零為起始的起始索引。

match: Predicate<T>

定義要搜尋項目之條件的 Predicate<T> 委派。

傳回

Int32

符合 match 所定義條件的元素，最後一次出現項目之以零為起始的索引 (若有找到)，否則為 -1。

例外狀況

ArgumentNullException

match 為 null。

ArgumentOutOfRangeException

startIndex 超出 List<T> 的有效索引範圍。

備註

會 List<T> 從 startIndex 第一個元素開始向後搜尋，並結束。

Predicate<T>是方法的委派，如果傳遞給它的物件符合委派中定義的條件，則會傳回 true 。目前 List<T> 的專案會個別傳遞至 Predicate<T> 委派。

這個方法會執行線性搜尋;因此，這個方法是 O (n) 運算，其中 n 是從開頭 List<T> 到 startIndex的項目數目。

另請參閱

適用於

FindLastIndex(Int32, Int32, Predicate<T>)

來源:: List.cs

來源:: List.cs

來源:: List.cs

搜尋符合指定之述詞所定義的條件之項目，並傳回 List<T> 中包含指定之項目數目，且結束於指定之索引的項目範圍內最後一個符合項目之以零為起始的索引。

public:
 int FindLastIndex(int startIndex, int count, Predicate<T> ^ match);

public int FindLastIndex (int startIndex, int count, Predicate<T> match);

member this.FindLastIndex : int * int * Predicate<'T> -> int

Public Function FindLastIndex (startIndex As Integer, count As Integer, match As Predicate(Of T)) As Integer

參數

startIndex: Int32

向後搜尋之以零為起始的起始索引。

count: Int32

區段中要搜尋的項目數目。

match: Predicate<T>

定義要搜尋項目之條件的 Predicate<T> 委派。

傳回

Int32

符合 match 所定義條件的元素，最後一次出現項目之以零為起始的索引 (若有找到)，否則為 -1。

例外狀況

ArgumentNullException

match 為 null。

ArgumentOutOfRangeException

startIndex 超出 List<T> 的有效索引範圍。

-或-

count 小於 0。

-或-

startIndex 和 count 不指定 List<T> 的有效區段。

範例

下表描述為尋找方法提供的範例。

方法	範例
Find(Predicate<T>)	使用 `IDToFind` 述詞委派依標識符尋找書籍。 C# 範例使用匿名委派。
FindAll(Predicate<T>)	使用述詞委派尋找其 `Genre` 屬性為「Computer」 `FindComputer` 的所有書籍。
FindLast(Predicate<T>)	使用 `PubBefore2001` 述詞委派，尋找在 2001 年之前具有發行日期之集合中的最後一本書。 C# 範例使用匿名委派。
FindIndex(Predicate<T>)	使用述詞委派尋找第一部計算機書籍的 `FindComputer` 索引。
FindLastIndex(Predicate<T>)	使用述詞委派尋找最後一部計算機書籍的 `FindComputer` 索引。
FindIndex(Int32, Int32, Predicate<T>)	使用 `FindComputer` 述詞委派，在集合的第二半尋找第一部計算機書籍的索引。
FindLastIndex(Int32, Int32, Predicate<T>)	使用 `FindComputer` 述詞委派，在集合的第二半尋找最後一部計算機書籍的索引。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml.Linq;

namespace Find
{
    class Program
    {
        private static string IDtoFind = "bk109";

        private static List<Book> Books = new List<Book>();
        public static void Main(string[] args)
        {
            FillList();

            // Find a book by its ID.
            Book result = Books.Find(
            delegate(Book bk)
            {
                return bk.ID == IDtoFind;
            }
            );
            if (result != null)
            {
                DisplayResult(result, "Find by ID: " + IDtoFind);
            }
            else
            {
                Console.WriteLine("\nNot found: {0}", IDtoFind);
            }

            // Find last book in collection published before 2001.
            result = Books.FindLast(
            delegate(Book bk)
            {
                DateTime year2001 = new DateTime(2001,01,01);
                return bk.Publish_date < year2001;
            });
            if (result != null)
            {
                DisplayResult(result, "Last book in collection published before 2001:");
            }
            else
            {
                Console.WriteLine("\nNot found: {0}", IDtoFind);
            }

            // Find all computer books.
            List<Book> results = Books.FindAll(FindComputer);
            if (results.Count != 0)
            {
                DisplayResults(results, "All computer:");
            }
            else
            {
                Console.WriteLine("\nNo books found.");
            }

            // Find all books under $10.00.
            results = Books.FindAll(
            delegate(Book bk)
            {
                return bk.Price < 10.00;
            }
            );
            if (results.Count != 0)
            {
                DisplayResults(results, "Books under $10:");
            }
            else
            {
                Console.WriteLine("\nNo books found.");
            }

            // Find index values.
            Console.WriteLine();
            int ndx = Books.FindIndex(FindComputer);
            Console.WriteLine("Index of first computer book: {0}", ndx);
            ndx = Books.FindLastIndex(FindComputer);
            Console.WriteLine("Index of last computer book: {0}", ndx);

            int mid = Books.Count / 2;
            ndx = Books.FindIndex(mid, mid, FindComputer);
            Console.WriteLine("Index of first computer book in the second half of the collection: {0}", ndx);

            ndx = Books.FindLastIndex(Books.Count - 1, mid, FindComputer);
            Console.WriteLine("Index of last computer book in the second half of the collection: {0}", ndx);
        }

        // Populates the list with sample data.
        private static void FillList()
        {

            // Create XML elements from a source file.
            XElement xTree = XElement.Load(@"c:\temp\books.xml");

            // Create an enumerable collection of the elements.
            IEnumerable<XElement> elements = xTree.Elements();

            // Evaluate each element and set set values in the book object.
            foreach (XElement el in elements)
            {
                Book book = new Book();
                book.ID = el.Attribute("id").Value;
                IEnumerable<XElement> props = el.Elements();
                foreach (XElement p in props)
                {

                    if (p.Name.ToString().ToLower() == "author")
                    {
                        book.Author = p.Value;
                    }
                    else if (p.Name.ToString().ToLower() == "title")
                    {
                        book.Title = p.Value;
                    }
                    else if (p.Name.ToString().ToLower() == "genre")
                    {
                        book.Genre = p.Value;
                    }
                    else if (p.Name.ToString().ToLower() == "price")
                    {
                        book.Price = Convert.ToDouble(p.Value);
                    }
                    else if (p.Name.ToString().ToLower() == "publish_date")
                    {
                        book.Publish_date = Convert.ToDateTime(p.Value);
                    }
                    else if (p.Name.ToString().ToLower() == "description")
                    {
                        book.Description = p.Value;
                    }
                }

                Books.Add(book);
            }

            DisplayResults(Books, "All books:");
        }

        // Explicit predicate delegate.
        private static bool FindComputer(Book bk)
        {

            if (bk.Genre == "Computer")
            {
                return true;
            }
        else
            {
                return false;
            }
        }

        private static void DisplayResult(Book result, string title)
        {
            Console.WriteLine();
            Console.WriteLine(title);
            Console.WriteLine("\n{0}\t{1}\t{2}\t{3}\t{4}\t{5}", result.ID,
                result.Author, result.Title, result.Genre, result.Price,
                result.Publish_date.ToShortDateString());
            Console.WriteLine();
        }

        private static void DisplayResults(List<Book> results, string title)
        {
            Console.WriteLine();
            Console.WriteLine(title);
            foreach (Book b in results)
            {

                Console.Write("\n{0}\t{1}\t{2}\t{3}\t{4}\t{5}", b.ID,
                    b.Author, b.Title, b.Genre, b.Price,
                    b.Publish_date.ToShortDateString());
            }
            Console.WriteLine();
        }
    }

    public class Book
    {
        public string ID { get; set; }
        public string Author { get; set; }
        public string Title { get; set; }
        public string Genre { get; set; }
        public double Price { get; set; }
        public DateTime Publish_date { get; set; }
        public string Description { get; set; }
    }
}

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)


    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

備註

如果大於 0，則會List<T>從開始向後startIndex搜尋，count且結尾為startIndex減號count加上 1。

Predicate<T>是方法的委派，如果傳遞給它的物件符合委派中定義的條件，則會傳回 true 。目前 List<T> 的專案會個別傳遞至 Predicate<T> 委派。

這個方法會執行線性搜尋;因此，這個方法是 o (n) 運算，其中 n 是 count。

另請參閱

適用於

List<T>.FindLastIndex 方法

定義

多載

FindLastIndex(Predicate<T>)

參數

傳回

例外狀況

範例

備註

另請參閱

適用於

FindLastIndex(Int32, Predicate<T>)

參數

傳回

例外狀況

備註

另請參閱

適用於

FindLastIndex(Int32, Int32, Predicate<T>)

參數

傳回

例外狀況

範例

備註

另請參閱

適用於

意見反應

其他資源