IDictionary.Keys 属性

定义

获取 ICollection 对象,它包含 IDictionary 对象的键。Gets an ICollection object containing the keys of the IDictionary object.

public:
 property System::Collections::ICollection ^ Keys { System::Collections::ICollection ^ get(); };
public System.Collections.ICollection Keys { get; }
member this.Keys : System.Collections.ICollection
Public ReadOnly Property Keys As ICollection

属性值

ICollection 对象,它包含 IDictionary 对象的键。An ICollection object containing the keys of the IDictionary object.

示例

下面的代码示例演示如何实现 Keys 属性。The following code example demonstrates how to implement the Keys property. 此代码示例是为 IDictionary 类提供的更大示例的一部分。This code example is part of a larger example provided for the IDictionary class.

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 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 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

注解

返回 ICollection 对象中的键的顺序未指定,但保证其顺序与 Values 属性返回的 ICollection 中的相应值顺序相同。The order of the keys in the returned ICollection object is unspecified, but is guaranteed to be the same order as the corresponding values in the ICollection returned by the Values property.

适用于

另请参阅