DictionaryEntry 结构
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
定义可设置或检索的字典键/值对。
public value class DictionaryEntryC#
public struct DictionaryEntryC#
[System.Serializable]
public struct DictionaryEntryC#
[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public struct DictionaryEntrytype DictionaryEntry = struct[<System.Serializable>]
type DictionaryEntry = struct[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type DictionaryEntry = structPublic Structure DictionaryEntry- 继承
- 属性
下面的示例演示如何使用 DictionaryEntry 来循环访问 Hashtable 对象。
// A simple example for the DictionaryEntry structure.
using namespace System;
using namespace System::Collections;
public ref class Example
{
public:
static void Main()
{
// Create a new hash table.
//
Hashtable^ openWith = gcnew Hashtable();
// Add some elements to the hash table. There are no
// duplicate keys, but some of the values are duplicates.
openWith->Add("txt", "notepad.exe");
openWith->Add("bmp", "paint.exe");
openWith->Add("dib", "paint.exe");
openWith->Add("rtf", "wordpad.exe");
// When you use foreach to enumerate hash table elements,
// the elements are retrieved as DictionaryEntry objects.
Console::WriteLine();
for each (DictionaryEntry de in openWith)
{
Console::WriteLine("Key = {0}, Value = {1}", de.Key, de.Value);
}
}
};
int main()
{
Example::Main();
}
/* This code example produces output similar to the following:
Key = rtf, Value = wordpad.exe
Key = txt, Value = notepad.exe
Key = dib, Value = paint.exe
Key = bmp, Value = paint.exe
*/
C#
// A simple example for the DictionaryEntry structure.
using System;
using System.Collections;
class Example
{
public static void Main()
{
// Create a new hash table.
//
Hashtable openWith = new Hashtable();
// Add some elements to the hash table. There are no
// duplicate keys, but some of the values are duplicates.
openWith.Add("txt", "notepad.exe");
openWith.Add("bmp", "paint.exe");
openWith.Add("dib", "paint.exe");
openWith.Add("rtf", "wordpad.exe");
// When you use foreach to enumerate hash table elements,
// the elements are retrieved as DictionaryEntry objects.
Console.WriteLine();
foreach (DictionaryEntry de in openWith)
{
Console.WriteLine("Key = {0}, Value = {1}", de.Key, de.Value);
}
}
}
/* This code example produces output similar to the following:
Key = rtf, Value = wordpad.exe
Key = txt, Value = notepad.exe
Key = dib, Value = paint.exe
Key = bmp, Value = paint.exe
*/
'A simple example for the DictionaryEntry structure.
Imports System.Collections
Module Example
Sub Main()
' Create a new hash table.
'
Dim openWith As New Hashtable()
' Add some elements to the hash table. There are no
' duplicate keys, but some of the values are duplicates.
openWith.Add("txt", "notepad.exe")
openWith.Add("bmp", "paint.exe")
openWith.Add("dib", "paint.exe")
openWith.Add("rtf", "wordpad.exe")
' When you use For Each to enumerate hash table elements,
' the elements are retrieved as DictionaryEntry objects.
Console.WriteLine()
For Each de As DictionaryEntry In openWith
Console.WriteLine("Key = {0}, Value = {1}", _
de.Key, de.Value)
Next de
End Sub
End Module
' This code example produces output similar to the following:
'
'Key = rtf, Value = wordpad.exe
'Key = txt, Value = notepad.exe
'Key = dib, Value = paint.exe
'Key = bmp, Value = paint.exe
方法 IDictionaryEnumerator.Entry 返回此类型的实例。
重要
建议不要使用 DictionaryEntry 结构进行新的开发。 相反，我们建议将泛型 KeyValuePair<TKey,TValue> 结构与 类一起使用 Dictionary<TKey,TValue> 。 有关详细信息，请参阅 GitHub 上 不应使用非泛型集合 。
C# foreach 语句和 Visual Basic For Each 语句需要集合中每个元素的类型。 由于 的每个 IDictionary 元素都是键/值对，因此元素类型不是键的类型或值的类型。 相反，元素类型为 DictionaryEntry。 例如：
for each (DictionaryEntry de in openWith)
{
Console::WriteLine("Key = {0}, Value = {1}", de.Key, de.Value);
}
C#
foreach (DictionaryEntry de in openWith)
{
Console.WriteLine("Key = {0}, Value = {1}", de.Key, de.Value);
}
For Each de As DictionaryEntry In openWith
Console.WriteLine("Key = {0}, Value = {1}", _
de.Key, de.Value)
Next de
语句 foreach 是枚举器的包装器，它只允许读取集合，而不允许写入集合。
|
Dictionary |
使用指定的键和值初始化 DictionaryEntry 类型的实例。 |
| 产品 | 版本 |
|---|---|
| .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 |
| .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 |
