IDictionary インターフェイス

リファレンス

定義

名前空間:: System.Collections

アセンブリ:: mscorlib.dll, System.Runtime.dll

アセンブリ:: netstandard.dll, System.Runtime.dll

アセンブリ:: System.Runtime.dll

アセンブリ:: mscorlib.dll

アセンブリ:: netstandard.dll

重要

一部の情報は、リリース前に大きく変更される可能性があるプレリリースされた製品に関するものです。 Microsoft は、ここに記載されている情報について、明示または黙示を問わず、一切保証しません。

キーと値のペアの非ジェネリックコレクションを表します。

public interface class IDictionary : System::Collections::ICollection

public interface IDictionary : System.Collections.ICollection

[System.Runtime.InteropServices.ComVisible(true)]
public interface IDictionary : System.Collections.ICollection

type IDictionary = interface
    interface ICollection
    interface IEnumerable

[<System.Runtime.InteropServices.ComVisible(true)>]
type IDictionary = interface
    interface ICollection
    interface IEnumerable

Public Interface IDictionary
Implements ICollection

派生: System.Activities.Presentation.Model.ModelItemDictionary

System.Collections.Concurrent.ConcurrentDictionary<TKey,TValue>

System.Collections.DictionaryBase

System.Collections.Frozen.FrozenDictionary<TKey,TValue>

System.Collections.Generic.Dictionary<TKey,TValue>

その他…

属性: ComVisibleAttribute

実装: ICollection IEnumerable

例

次のコード例では、IDictionary インターフェイスを実装する単純なディクショナリクラスを定義する方法を示します。

using namespace System;
using namespace System::Collections;

// This class implements a simple dictionary using an array of
// DictionaryEntry objects (key/value pairs).
public ref class SimpleDictionary : public IDictionary
{
    // The array of items
private:
    array<DictionaryEntry^>^ items;
private:
    int itemsInUse;

    // Construct the SimpleDictionary with the desired number of
    // items. The number of items cannot change for the life time of
    // this SimpleDictionary.
public:
    SimpleDictionary(int size)
    {
        items = gcnew array<DictionaryEntry^>(size);
    }

    #pragma region IDictionary Members
public:
    property virtual bool IsReadOnly
    {
        bool get()
        {
            return false;
        }
    }
public:
    virtual bool Contains(Object^ key)
    {
        int index;
        return TryGetIndexOfKey(key, &index);
    }
public:
    virtual property bool IsFixedSize
    {
        bool get()
        {
            return false;
        }
    }
public:
    virtual void Remove(Object^ key)
    {
        if (key == nullptr)
        {
            throw gcnew ArgumentNullException("key");
        }
        // Try to find the key in the DictionaryEntry array
        int index;
        if (TryGetIndexOfKey(key, &index))
        {
            // If the key is found, slide all the items down.
            Array::Copy(items, index + 1, items, index, itemsInUse -
                index - 1);
            itemsInUse--;
        }
        else
        {
            // If the key is not in the dictionary, just return.
            return;
        }
    }
public:
    virtual void Clear()
    {
        itemsInUse = 0;
    }
public:
    virtual void Add(Object^ key, Object^ value)
    {
        // Add the new key/value pair even if this key already exists
        // in the dictionary.
        if (itemsInUse == items->Length)
        {
            throw gcnew InvalidOperationException
                ("The dictionary cannot hold any more items.");
        }
        items[itemsInUse++] = gcnew DictionaryEntry(key, value);
    }
public:
    virtual property ICollection^ Keys
    {
        ICollection^ get()
        {
            // Return an array where each item is a key.
            array<Object^>^ keys = gcnew array<Object^>(itemsInUse);
            for (int i = 0; i < itemsInUse; i++)
            {
                keys[i] = items[i]->Key;
            }
            return keys;
        }
    }
public:
    virtual property ICollection^ Values
    {
        ICollection^ get()
        {
            // Return an array where each item is a value.
            array<Object^>^ values = gcnew array<Object^>(itemsInUse);
            for (int i = 0; i < itemsInUse; i++)
            {
                values[i] = items[i]->Value;
            }
            return values;
        }
    }
public:
    virtual property Object^ default[Object^]
    {
        Object^ get(Object^ key)
        {
            // If this key is in the dictionary, return its value.
            int index;
            if (TryGetIndexOfKey(key, &index))
            {
                // The key was found; return its value.
                return items[index]->Value;
            }
            else
            {
                // The key was not found; return null.
                return nullptr;
            }
        }

        void set(Object^ key, Object^ value)
        {
            // If this key is in the dictionary, change its value.
            int index;
            if (TryGetIndexOfKey(key, &index))
            {
                // The key was found; change its value.
                items[index]->Value = value;
            }
            else
            {
                // This key is not in the dictionary; add this
                // key/value pair.
                Add(key, value);
            }
        }
    }
private:
    bool TryGetIndexOfKey(Object^ key, int* index)
    {
        for (*index = 0; *index < itemsInUse; *index++)
        {
            // If the key is found, return true (the index is also
            // returned).
            if (items[*index]->Key->Equals(key))
            {
                return true;
            }
        }

        // Key not found, return false (index should be ignored by
        // the caller).
        return false;
    }
private:
    ref class SimpleDictionaryEnumerator : public IDictionaryEnumerator
    {
        // A copy of the SimpleDictionary object's key/value pairs.
private:
        array<DictionaryEntry^>^ items;
private:
        int index;

public:
        SimpleDictionaryEnumerator(SimpleDictionary^ sd)
        {
            // Make a copy of the dictionary entries currently in the
            // SimpleDictionary object.
            items = gcnew array<DictionaryEntry^>(sd->Count);
            Array::Copy(sd->items, 0, items, 0, sd->Count);
            index = -1;
        }

        // Return the current item.
public:
        virtual property Object^ Current
        {
            Object^ get()
            {
                ValidateIndex();
                return items[index];
            }
        }

        // Return the current dictionary entry.
public:
        virtual property DictionaryEntry Entry
        {
            DictionaryEntry get()
            {
                return (DictionaryEntry) Current;
            }
        }

        // Return the key of the current item.
public:
        virtual property Object^ Key
        {
            Object^ get()
            {
                ValidateIndex();
                return items[index]->Key;
            }
        }

        // Return the value of the current item.
public:
        virtual property Object^ Value
        {
            Object^ get()
            {
                ValidateIndex();
                return items[index]->Value;
            }
        }

        // Advance to the next item.
public:
        virtual bool MoveNext()
        {
            if (index < items->Length - 1)
            {
                index++;
                return true;
            }
            return false;
        }

        // Validate the enumeration index and throw an exception if
        // the index is out of range.
private:
        void ValidateIndex()
        {
            if (index < 0 || index >= items->Length)
            {
                throw gcnew InvalidOperationException
                    ("Enumerator is before or after the collection.");
            }
        }

        // Reset the index to restart the enumeration.
public:
        virtual void Reset()
        {
            index = -1;
        }
    };
public:
    virtual IDictionaryEnumerator^ GetEnumerator()
    {
        // Construct and return an enumerator.
        return gcnew SimpleDictionaryEnumerator(this);
    }
    #pragma endregion

    #pragma region ICollection Members
public:
    virtual property bool IsSynchronized
    {
        bool get()
        {
            return false;
        }
    }

public:
    virtual property Object^ SyncRoot
    {
        Object^ get()
        {
            throw gcnew NotImplementedException();
        }
    }

public:
    virtual property int Count
    {
        int get()
        {
            return itemsInUse;
        }
    }

public:
    virtual void CopyTo(Array^ array, int index)
    {
        throw gcnew NotImplementedException();
    }
    #pragma endregion

    #pragma region IEnumerable Members

    virtual IEnumerator^ IEnumerable_GetEnumerator() 
        = IEnumerable::GetEnumerator
    {
        // Construct and return an enumerator.
        return ((IDictionary^)this)->GetEnumerator();
    }
    #pragma endregion
};

int main()
{
    // Create a dictionary that contains no more than three
    // entries.
    IDictionary^ d = gcnew SimpleDictionary(3);

    // Add three people and their ages to the dictionary.
    d->Add("Jeff", 40);
    d->Add("Kristin", 34);
    d->Add("Aidan", 1);

    Console::WriteLine("Number of elements in dictionary = {0}",
        d->Count);

    Console::WriteLine("Does dictionary contain 'Jeff'? {0}",
        d->Contains("Jeff"));
    Console::WriteLine("Jeff's age is {0}", d["Jeff"]);

    // Display every entry's key and value.
    for each (DictionaryEntry^ de in d)
    {
        Console::WriteLine("{0} is {1} years old.", de->Key,
            de->Value);
    }

    // Remove an entry that exists.
    d->Remove("Jeff");

    // Remove an entry that does not exist, but do not throw an
    // exception.
    d->Remove("Max");

    // Show the names (keys) of the people in the dictionary.
    for each (String^ s in d->Keys)
    {
        Console::WriteLine(s);
    }

    // Show the ages (values) of the people in the dictionary.
    for each (int age in d->Values)
    {
        Console::WriteLine(age);
    }
}

// This code produces the following output.
//
// Number of elements in dictionary = 3
// Does dictionary contain 'Jeff'? True
// Jeff's age is 40
// Jeff is 40 years old.
// Kristin is 34 years old.
// Aidan is 1 years old.
// Kristin
// Aidan
// 34
// 1

using System;
using System.Collections;

// This class implements a simple dictionary using an array of DictionaryEntry objects (key/value pairs).
public class SimpleDictionary : IDictionary
{
    // The array of items
    private DictionaryEntry[] items;
    private Int32 ItemsInUse = 0;

    // Construct the SimpleDictionary with the desired number of items.
    // The number of items cannot change for the life time of this SimpleDictionary.
    public SimpleDictionary(Int32 numItems)
    {
        items = new DictionaryEntry[numItems];
    }

    #region IDictionary Members
    public bool IsReadOnly { get { return false; } }
    public bool Contains(object key)
    {
       Int32 index;
       return TryGetIndexOfKey(key, out index);
    }
    public bool IsFixedSize { get { return false; } }
    public void Remove(object key)
    {
        if (key == null) throw new ArgumentNullException("key");
        // Try to find the key in the DictionaryEntry array
        Int32 index;
        if (TryGetIndexOfKey(key, out index))
        {
            // If the key is found, slide all the items up.
            Array.Copy(items, index + 1, items, index, ItemsInUse - index - 1);
            ItemsInUse--;
        }
        else
        {
            // If the key is not in the dictionary, just return.
        }
    }
    public void Clear() { ItemsInUse = 0; }
    public void Add(object key, object value)
    {
        // Add the new key/value pair even if this key already exists in the dictionary.
        if (ItemsInUse == items.Length)
            throw new InvalidOperationException("The dictionary cannot hold any more items.");
        items[ItemsInUse++] = new DictionaryEntry(key, value);
    }
    public ICollection Keys
    {
        get
        {
            // Return an array where each item is a key.
            Object[] keys = new Object[ItemsInUse];
            for (Int32 n = 0; n < ItemsInUse; n++)
                keys[n] = items[n].Key;
            return keys;
        }
    }
    public ICollection Values
    {
        get
        {
            // Return an array where each item is a value.
            Object[] values = new Object[ItemsInUse];
            for (Int32 n = 0; n < ItemsInUse; n++)
                values[n] = items[n].Value;
            return values;
        }
    }
    public object this[object key]
    {
        get
        {
            // If this key is in the dictionary, return its value.
            Int32 index;
            if (TryGetIndexOfKey(key, out index))
            {
                // The key was found; return its value.
                return items[index].Value;
            }
            else
            {
                // The key was not found; return null.
                return null;
            }
        }

        set
        {
            // If this key is in the dictionary, change its value.
            Int32 index;
            if (TryGetIndexOfKey(key, out index))
            {
                // The key was found; change its value.
                items[index].Value = value;
            }
            else
            {
                // This key is not in the dictionary; add this key/value pair.
                Add(key, value);
            }
        }
    }
    private Boolean TryGetIndexOfKey(Object key, out Int32 index)
    {
        for (index = 0; index < ItemsInUse; index++)
        {
            // If the key is found, return true (the index is also returned).
            if (items[index].Key.Equals(key)) return true;
        }

        // Key not found, return false (index should be ignored by the caller).
        return false;
    }
    private class SimpleDictionaryEnumerator : IDictionaryEnumerator
    {
        // A copy of the SimpleDictionary object's key/value pairs.
        DictionaryEntry[] items;
        Int32 index = -1;

        public SimpleDictionaryEnumerator(SimpleDictionary sd)
        {
            // Make a copy of the dictionary entries currently in the SimpleDictionary object.
            items = new DictionaryEntry[sd.Count];
            Array.Copy(sd.items, 0, items, 0, sd.Count);
        }

        // Return the current item.
        public Object Current { get { ValidateIndex(); return items[index]; } }

        // Return the current dictionary entry.
        public DictionaryEntry Entry
        {
            get { return (DictionaryEntry) Current; }
        }

        // Return the key of the current item.
        public Object Key { get { ValidateIndex();  return items[index].Key; } }

        // Return the value of the current item.
        public Object Value { get { ValidateIndex();  return items[index].Value; } }

        // Advance to the next item.
        public Boolean MoveNext()
        {
            if (index < items.Length - 1) { index++; return true; }
            return false;
        }

        // Validate the enumeration index and throw an exception if the index is out of range.
        private void ValidateIndex()
        {
            if (index < 0 || index >= items.Length)
            throw new InvalidOperationException("Enumerator is before or after the collection.");
        }

        // Reset the index to restart the enumeration.
        public void Reset()
        {
            index = -1;
        }
    }
    public IDictionaryEnumerator GetEnumerator()
    {
        // Construct and return an enumerator.
        return new SimpleDictionaryEnumerator(this);
    }
    #endregion

    #region ICollection Members
    public bool IsSynchronized { get { return false; } }
    public object SyncRoot { get { throw new NotImplementedException(); } }
    public int Count { get { return ItemsInUse; } }
    public void CopyTo(Array array, int index) { throw new NotImplementedException(); }
    #endregion

    #region IEnumerable Members
    IEnumerator IEnumerable.GetEnumerator()
    {
        // Construct and return an enumerator.
        return ((IDictionary)this).GetEnumerator();
    }
    #endregion
}

public sealed class App
{
    static void Main()
    {
        // Create a dictionary that contains no more than three entries.
        IDictionary d = new SimpleDictionary(3);

        // Add three people and their ages to the dictionary.
        d.Add("Jeff", 40);
        d.Add("Kristin", 34);
        d.Add("Aidan", 1);

        Console.WriteLine("Number of elements in dictionary = {0}", d.Count);

        Console.WriteLine("Does dictionary contain 'Jeff'? {0}", d.Contains("Jeff"));
        Console.WriteLine("Jeff's age is {0}", d["Jeff"]);

        // Display every entry's key and value.
        foreach (DictionaryEntry de in d)
        {
            Console.WriteLine("{0} is {1} years old.", de.Key, de.Value);
        }

        // Remove an entry that exists.
        d.Remove("Jeff");

        // Remove an entry that does not exist, but do not throw an exception.
        d.Remove("Max");

        // Show the names (keys) of the people in the dictionary.
        foreach (String s in d.Keys)
            Console.WriteLine(s);

        // Show the ages (values) of the people in the dictionary.
        foreach (Int32 age in d.Values)
            Console.WriteLine(age);
    }
}

// This code produces the following output.
//
// Number of elements in dictionary = 3
// Does dictionary contain 'Jeff'? True
// Jeff's age is 40
// Jeff is 40 years old.
// Kristin is 34 years old.
// Aidan is 1 years old.
// Kristin
// Aidan
// 34
// 1

Imports System.Collections

' This class implements a simple dictionary using an array of DictionaryEntry objects (key/value pairs).
Public Class SimpleDictionary
    Implements IDictionary

    ' The array of items
    Dim items() As DictionaryEntry
    Dim ItemsInUse As Integer = 0

    ' Construct the SimpleDictionary with the desired number of items.
    ' The number of items cannot change for the life time of this SimpleDictionary.
    Public Sub New(ByVal numItems As Integer)
        items = New DictionaryEntry(numItems - 1) {}
    End Sub

    ' IDictionary Members
    Public ReadOnly Property IsReadOnly() As Boolean Implements IDictionary.IsReadOnly
        Get
            Return False
        End Get
    End Property

    Public Function Contains(ByVal key As Object) As Boolean Implements IDictionary.Contains
        Dim index As Integer
        Return TryGetIndexOfKey(key, index)
    End Function

    Public ReadOnly Property IsFixedSize() As Boolean Implements IDictionary.IsFixedSize
        Get
            Return False
        End Get
    End Property

    Public Sub Remove(ByVal key As Object) Implements IDictionary.Remove
        If key = Nothing Then
            Throw New ArgumentNullException("key")
        End If
        ' Try to find the key in the DictionaryEntry array
        Dim index As Integer
        If TryGetIndexOfKey(key, index) Then

            ' If the key is found, slide all the items up.
            Array.Copy(items, index + 1, items, index, (ItemsInUse - index) - 1)
            ItemsInUse = ItemsInUse - 1
        Else

            ' If the key is not in the dictionary, just return. 
        End If
    End Sub

    Public Sub Clear() Implements IDictionary.Clear
        ItemsInUse = 0
    End Sub

    Public Sub Add(ByVal key As Object, ByVal value As Object) Implements IDictionary.Add

        ' Add the new key/value pair even if this key already exists in the dictionary.
        If ItemsInUse = items.Length Then
            Throw New InvalidOperationException("The dictionary cannot hold any more items.")
        End If
        items(ItemsInUse) = New DictionaryEntry(key, value)
        ItemsInUse = ItemsInUse + 1
    End Sub

    Public ReadOnly Property Keys() As ICollection Implements IDictionary.Keys
        Get

            ' Return an array where each item is a key.
            ' Note: Declaring keyArray() to have a size of ItemsInUse - 1
            '       ensures that the array is properly sized, in VB.NET
            '       declaring an array of size N creates an array with
            '       0 through N elements, including N, as opposed to N - 1
            '       which is the default behavior in C# and C++.
            Dim keyArray() As Object = New Object(ItemsInUse - 1) {}
            Dim n As Integer
            For n = 0 To ItemsInUse - 1
                keyArray(n) = items(n).Key
            Next n

            Return keyArray
        End Get
    End Property

    Public ReadOnly Property Values() As ICollection Implements IDictionary.Values
        Get
            ' Return an array where each item is a value.
            Dim valueArray() As Object = New Object(ItemsInUse - 1) {}
            Dim n As Integer
            For n = 0 To ItemsInUse - 1
                valueArray(n) = items(n).Value
            Next n

            Return valueArray
        End Get
    End Property

    Public Property Item(ByVal key As Object) As Object Implements IDictionary.Item
        Get

            ' If this key is in the dictionary, return its value.
            Dim index As Integer
            If TryGetIndexOfKey(key, index) Then

                ' The key was found return its value.
                Return items(index).Value
            Else

                ' The key was not found return null.
                Return Nothing
            End If
        End Get

        Set(ByVal value As Object)
            ' If this key is in the dictionary, change its value. 
            Dim index As Integer
            If TryGetIndexOfKey(key, index) Then

                ' The key was found change its value.
                items(index).Value = value
            Else

                ' This key is not in the dictionary add this key/value pair.
                Add(key, value)
            End If
        End Set
    End Property

    Private Function TryGetIndexOfKey(ByVal key As Object, ByRef index As Integer) As Boolean
        For index = 0 To ItemsInUse - 1
            ' If the key is found, return true (the index is also returned).
            If items(index).Key.Equals(key) Then
                Return True
            End If
        Next index

        ' Key not found, return false (index should be ignored by the caller).
        Return False
    End Function

    Private Class SimpleDictionaryEnumerator
        Implements IDictionaryEnumerator

        ' A copy of the SimpleDictionary object's key/value pairs.
        Dim items() As DictionaryEntry
        Dim index As Integer = -1

        Public Sub New(ByVal sd As SimpleDictionary)
            ' Make a copy of the dictionary entries currently in the SimpleDictionary object.
            items = New DictionaryEntry(sd.Count - 1) {}
            Array.Copy(sd.items, 0, items, 0, sd.Count)
        End Sub

        ' Return the current item.
        Public ReadOnly Property Current() As Object Implements IDictionaryEnumerator.Current
            Get
                ValidateIndex()
                Return items(index)
            End Get
        End Property

        ' Return the current dictionary entry.
        Public ReadOnly Property Entry() As DictionaryEntry Implements IDictionaryEnumerator.Entry
            Get
                Return Current
            End Get
        End Property

        ' Return the key of the current item.
        Public ReadOnly Property Key() As Object Implements IDictionaryEnumerator.Key
            Get
                ValidateIndex()
                Return items(index).Key
            End Get
        End Property

        ' Return the value of the current item.
        Public ReadOnly Property Value() As Object Implements IDictionaryEnumerator.Value
            Get
                ValidateIndex()
                Return items(index).Value
            End Get
        End Property

        ' Advance to the next item.
        Public Function MoveNext() As Boolean Implements IDictionaryEnumerator.MoveNext
            If index < items.Length - 1 Then
                index = index + 1
                Return True
            End If

            Return False
        End Function

        ' Validate the enumeration index and throw an exception if the index is out of range.
        Private Sub ValidateIndex()
            If index < 0 Or index >= items.Length Then
                Throw New InvalidOperationException("Enumerator is before or after the collection.")
            End If
        End Sub

        ' Reset the index to restart the enumeration.
        Public Sub Reset() Implements IDictionaryEnumerator.Reset
            index = -1
        End Sub

    End Class

    Public Function GetEnumerator() As IDictionaryEnumerator Implements IDictionary.GetEnumerator

        'Construct and return an enumerator.
        Return New SimpleDictionaryEnumerator(Me)
    End Function


    ' ICollection Members
    Public ReadOnly Property IsSynchronized() As Boolean Implements IDictionary.IsSynchronized
        Get
            Return False
        End Get
    End Property

    Public ReadOnly Property SyncRoot() As Object Implements IDictionary.SyncRoot
        Get
            Throw New NotImplementedException()
        End Get
    End Property

    Public ReadOnly Property Count() As Integer Implements IDictionary.Count
        Get
            Return ItemsInUse
        End Get
    End Property

    Public Sub CopyTo(ByVal array As Array, ByVal index As Integer) Implements IDictionary.CopyTo
        Throw New NotImplementedException()
    End Sub

    ' IEnumerable Members
    Public Function GetEnumerator1() As IEnumerator Implements IEnumerable.GetEnumerator

        ' Construct and return an enumerator.
        Return Me.GetEnumerator()
    End Function
End Class

Public NotInheritable Class App
    Public Shared Sub Main()
        ' Create a dictionary that contains no more than three entries.
        Dim d As IDictionary = New SimpleDictionary(3)

        ' Add three people and their ages to the dictionary.
        d.Add("Jeff", 40)
        d.Add("Kristin", 34)
        d.Add("Aidan", 1)

        Console.WriteLine("Number of elements in dictionary = {0}", d.Count)

        Console.WriteLine("Does dictionary contain 'Jeff'? {0}", d.Contains("Jeff"))
        Console.WriteLine("Jeff's age is {0}", d("Jeff"))

        ' Display every entry's key and value.
        Dim de As DictionaryEntry
        For Each de In d
            Console.WriteLine("{0} is {1} years old.", de.Key, de.Value)
        Next

        ' Remove an entry that exists.
        d.Remove("Jeff")

        ' Remove an entry that does not exist, but do not throw an exception.
        d.Remove("Max")

        ' Show the names (keys) of the people in the dictionary.
        Dim s As String

        For Each s In d.Keys
            Console.WriteLine(s)
        Next

        ' Show the ages (values) of the people in the dictionary.
        Dim age As Integer
        For Each age In d.Values
            Console.WriteLine(age)
        Next

    End Sub
End Class

' This code produces the following output.
'
' Number of elements in dictionary = 3
' Does dictionary contain 'Jeff'? True
' Jeff's age is 40
' Jeff is 40 years old.
' Kristin is 34 years old.
' Aidan is 1 years old.
' Kristin
' Aidan
' 34
' 1

注釈

IDictionary インターフェイスは、キーと値のペアの非ジェネリックコレクションの基本インターフェイスです。このインターフェイスの汎用バージョンについては、System.Collections.Generic.IDictionary<TKey,TValue>を参照してください。

各要素は、DictionaryEntry オブジェクトに格納されているキーと値のペアです。

各ペアには一意のキーが必要です。実装は、キーを null にできるかどうかによって異なる場合があります。値は null にすることができ、一意である必要はありません。 IDictionary インターフェイスでは、含まれているキーと値を列挙できますが、特定の並べ替え順序を意味するものではありません。

IDictionary 実装は、読み取り専用、固定サイズ、可変サイズの 3 つのカテゴリに分類されます。読み取り専用 IDictionary オブジェクトは変更できません。固定サイズの IDictionary オブジェクトでは、要素の追加または削除は許可されませんが、既存の要素の変更は可能です。可変サイズの IDictionary オブジェクトを使用すると、要素の追加、削除、および変更を行えます。

C# 言語の foreach ステートメント (Visual Basic のFor Each) は、コレクション内の要素の型のオブジェクトを返します。 IDictionary オブジェクトの各要素はキーと値のペアであるため、要素の型はキーの型または値の型ではありません。代わりに、要素型は DictionaryEntryです。例えば：

for each (DictionaryEntry de in myDictionary)
{
    //...
}

foreach (DictionaryEntry de in myDictionary)
{
    //...
}

For Each de As DictionaryEntry In myDictionary
    '...
Next de

foreach ステートメントは列挙子のラッパーであり、コレクションへの書き込みからの読み取りのみが許可されますが、コレクションへの書き込みは許可されません。

注意 (実装者)

実装クラスには、キーを比較する手段が必要です。

プロパティ

Count	ICollectionに含まれる要素の数を取得します。 (継承元 ICollection)
IsFixedSize	IDictionary オブジェクトのサイズが固定されているかどうかを示す値を取得します。
IsReadOnly	IDictionary オブジェクトが読み取り専用かどうかを示す値を取得します。
IsSynchronized	ICollection へのアクセスが同期されているかどうかを示す値を取得します (スレッドセーフ)。 (継承元 ICollection)
Item[Object]	指定したキーを持つ要素を取得または設定します。
Keys	IDictionary オブジェクトのキーを含む ICollection オブジェクトを取得します。
SyncRoot	ICollectionへのアクセスを同期するために使用できるオブジェクトを取得します。 (継承元 ICollection)
Values	IDictionary オブジェクト内の値を含む ICollection オブジェクトを取得します。

メソッド

Add(Object, Object)	指定されたキーと値を持つ要素を IDictionary オブジェクトに追加します。
Clear()	IDictionary オブジェクトからすべての要素を削除します。
Contains(Object)	IDictionary オブジェクトに、指定したキーを持つ要素が含まれているかどうかを判断します。
CopyTo(Array, Int32)	特定の Array インデックスから始まる ICollection の要素を Arrayにコピーします。 (継承元 ICollection)
GetEnumerator()	IDictionary オブジェクトの IDictionaryEnumerator オブジェクトを返します。
Remove(Object)	指定したキーを持つ要素を IDictionary オブジェクトから削除します。

拡張メソッド

Cast<TResult>(IEnumerable)	IEnumerable の要素を指定した型にキャストします。
OfType<TResult>(IEnumerable)	指定した型に基づいて、IEnumerable の要素をフィルター処理します。
AsParallel(IEnumerable)	クエリの並列化を有効にします。
AsQueryable(IEnumerable)	IEnumerable を IQueryableに変換します。

適用対象

製品	バージョン
.NET	Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1
UWP	10.0

次の方法で共有