IComparable 介面
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。
定義特定通用類型的比較方法，實值類型或類別會實作這個方法，以排列或排序其執行個體。
public interface class IComparableC#
public interface IComparableC#
[System.Runtime.InteropServices.ComVisible(true)]
public interface IComparabletype IComparable = interface[<System.Runtime.InteropServices.ComVisible(true)>]
type IComparable = interfacePublic Interface IComparable- 衍生
- 屬性
下列範例說明 和 必要 CompareTo 方法的實作 IComparable 。
using namespace System;
using namespace System::Collections;
public ref class Temperature: public IComparable {
/// <summary>
/// IComparable.CompareTo implementation.
/// </summary>
protected:
// The value holder
Double m_value;
public:
virtual Int32 CompareTo( Object^ obj ) {
if (obj == nullptr) return 1;
if ( obj->GetType() == Temperature::typeid ) {
Temperature^ temp = dynamic_cast<Temperature^>(obj);
return m_value.CompareTo( temp->m_value );
}
throw gcnew ArgumentException( "object is not a Temperature" );
}
property Double Value {
Double get() {
return m_value;
}
void set( Double value ) {
m_value = value;
}
}
property Double Celsius {
Double get() {
return (m_value - 32) / 1.8;
}
void set( Double value ) {
m_value = (value * 1.8) + 32;
}
}
};
int main()
{
ArrayList^ temperatures = gcnew ArrayList;
// Initialize random number generator.
Random^ rnd = gcnew Random;
// Generate 10 temperatures between 0 and 100 randomly.
for (int ctr = 1; ctr <= 10; ctr++)
{
int degrees = rnd->Next(0, 100);
Temperature^ temp = gcnew Temperature;
temp->Value = degrees;
temperatures->Add(temp);
}
// Sort ArrayList.
temperatures->Sort();
for each (Temperature^ temp in temperatures)
Console::WriteLine(temp->Value);
return 0;
}
// The example displays the following output to the console (individual
// values may vary because they are randomly generated):
// 2
// 7
// 16
// 17
// 31
// 37
// 58
// 66
// 72
// 95
C#
using System;
using System.Collections;
public class Temperature : IComparable
{
// The temperature value
protected double temperatureF;
public int CompareTo(object obj) {
if (obj == null) return 1;
Temperature otherTemperature = obj as Temperature;
if (otherTemperature != null)
return this.temperatureF.CompareTo(otherTemperature.temperatureF);
else
throw new ArgumentException("Object is not a Temperature");
}
public double Fahrenheit
{
get
{
return this.temperatureF;
}
set
{
this.temperatureF = value;
}
}
public double Celsius
{
get
{
return (this.temperatureF - 32) * (5.0/9);
}
set
{
this.temperatureF = (value * 9.0/5) + 32;
}
}
}
public class CompareTemperatures
{
public static void Main()
{
ArrayList temperatures = new ArrayList();
// Initialize random number generator.
Random rnd = new Random();
// Generate 10 temperatures between 0 and 100 randomly.
for (int ctr = 1; ctr <= 10; ctr++)
{
int degrees = rnd.Next(0, 100);
Temperature temp = new Temperature();
temp.Fahrenheit = degrees;
temperatures.Add(temp);
}
// Sort ArrayList.
temperatures.Sort();
foreach (Temperature temp in temperatures)
Console.WriteLine(temp.Fahrenheit);
}
}
// The example displays the following output to the console (individual
// values may vary because they are randomly generated):
// 2
// 7
// 16
// 17
// 31
// 37
// 58
// 66
// 72
// 95
open System
open System.Collections
type Temperature() =
// The temperature value
let mutable temperatureF = 0.
interface IComparable with
member _.CompareTo(obj) =
match obj with
| null -> 1
| :? Temperature as other ->
temperatureF.CompareTo other.Fahrenheit
| _ ->
invalidArg (nameof obj) "Object is not a Temperature"
member _.Fahrenheit
with get () =
temperatureF
and set (value) =
temperatureF <- value
member _.Celsius
with get () =
(temperatureF - 32.) * (5. / 9.)
and set (value) =
temperatureF <- (value * 9. / 5.) + 32.
let temperatures = ResizeArray()
// Initialize random number generator.
let rnd = Random()
// Generate 10 temperatures between 0 and 100 randomly.
for _ = 1 to 10 do
let degrees = rnd.Next(0, 100)
let temp = Temperature(Fahrenheit=degrees)
temperatures.Add temp
// Sort ResizeArray.
temperatures.Sort()
for temp in temperatures do
printfn $"{temp.Fahrenheit}"
// The example displays the following output to the console (individual
// values may vary because they are randomly generated):
// 2
// 7
// 16
// 17
// 31
// 37
// 58
// 66
// 72
// 95
Imports System.Collections
Public Class Temperature
Implements IComparable
' The temperature value
Protected temperatureF As Double
Public Overloads Function CompareTo(ByVal obj As Object) As Integer _
Implements IComparable.CompareTo
If obj Is Nothing Then Return 1
Dim otherTemperature As Temperature = TryCast(obj, Temperature)
If otherTemperature IsNot Nothing Then
Return Me.temperatureF.CompareTo(otherTemperature.temperatureF)
Else
Throw New ArgumentException("Object is not a Temperature")
End If
End Function
Public Property Fahrenheit() As Double
Get
Return temperatureF
End Get
Set(ByVal Value As Double)
Me.temperatureF = Value
End Set
End Property
Public Property Celsius() As Double
Get
Return (temperatureF - 32) * (5/9)
End Get
Set(ByVal Value As Double)
Me.temperatureF = (Value * 9/5) + 32
End Set
End Property
End Class
Public Module CompareTemperatures
Public Sub Main()
Dim temperatures As New ArrayList
' Initialize random number generator.
Dim rnd As New Random()
' Generate 10 temperatures between 0 and 100 randomly.
For ctr As Integer = 1 To 10
Dim degrees As Integer = rnd.Next(0, 100)
Dim temp As New Temperature
temp.Fahrenheit = degrees
temperatures.Add(temp)
Next
' Sort ArrayList.
temperatures.Sort()
For Each temp As Temperature In temperatures
Console.WriteLine(temp.Fahrenheit)
Next
End Sub
End Module
' The example displays the following output to the console (individual
' values may vary because they are randomly generated):
' 2
' 7
' 16
' 17
' 31
' 37
' 58
' 66
' 72
' 95
這個介面是由可排序或排序其值的類型所實作。 它需要實作型別定義單一方法 CompareTo(Object) ，指出目前實例在排序次序中的位置是之前、之後還是與相同類型的第二個物件相同。 實例的實作 IComparable 是由 和 ArrayList.Sort 之類的 Array.Sort 方法自動呼叫。
方法的實作 CompareTo(Object) 必須傳回 Int32 具有三個值之一的 ，如下表所示。
| 值 | 意義 |
|---|---|
| 小於零 | 目前實例在 排序次序中方法所 CompareTo 指定的 物件之前。 |
| 零 | 這個目前的實例會以與 方法所 CompareTo 指定的物件相同的排序次序位置發生。 |
| 大於零 | 這個目前的 實例會依照 排序次序中的 CompareTo 方法所指定的 物件。 |
所有數數值型別 (例如 和) 實 IComparable 作 、，如 、 CharString 、 和 DateTime 。 DoubleInt32 自訂類型也應該提供自己的 實 IComparable 作，讓物件實例能夠排序或排序。
|
Compare |
將目前的執行個體與相同類型的另一個物件相比較，並傳回整數，這個整數表示目前的執行個體在排序次序中，位於另一個物件之前、之後或相同位置。 |
| 產品 | 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, 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 |
