Tuple<T1,T2>.IStructuralEquatable.Equals 方法
定義
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。
傳回值，這個值表示依據指定的比較方法，目前的 Tuple<T1,T2> 物件是否等於指定的物件。
virtual bool System.Collections.IStructuralEquatable.Equals(System::Object ^ other, System::Collections::IEqualityComparer ^ comparer) = System::Collections::IStructuralEquatable::Equals;bool IStructuralEquatable.Equals (object other, System.Collections.IEqualityComparer comparer);abstract member System.Collections.IStructuralEquatable.Equals : obj * System.Collections.IEqualityComparer -> bool
override this.System.Collections.IStructuralEquatable.Equals : obj * System.Collections.IEqualityComparer -> boolFunction Equals (other As Object, comparer As IEqualityComparer) As Boolean Implements IStructuralEquatable.Equals參數
- other
- Object
與這個執行個體相互比較的物件。
- comparer
- IEqualityComparer
物件，定義要用來評估這兩個物件是否相等的方法。
傳回
如果目前的執行個體和指定的物件相等，則為 true，否則為 false。
實作
範例
下列範例會定義實 Item2Comparer 作 介面的類別， IEqualityComparer 並變更評估物件是否相等的方式 Tuple<T1,T2> 。 方法一律會在 true 傳遞 Item1 兩 Tuple<T1,T2> 個 物件的屬性值時傳回 ，並呼叫 IStructuralEquatable.Equals 方法來評估其 Item2 屬性值。 因此，方法只會根據 屬性的值 Item2 來測試是否相等。 輸出說明記錄執行器名稱及其執行距離之物件資料集 Tuple<T1,T2> 的結果。
using System;
using System.Collections;
public class Item2Comparer<T1, T2> : IEqualityComparer
{
new public bool Equals(object x, object y)
{
// Return true for all values of Item1.
if (x is T1)
//if (typeof(x) is string)
return true;
else
return x.Equals(y);
}
public int GetHashCode(object obj)
{
if (obj is T1)
return ((T1) obj).GetHashCode();
else
return ((T2) obj).GetHashCode();
}
}
public class Example
{
public static void Main()
{
Tuple<string, double>[] distancesWalked = {
Tuple.Create("Jan", Double.NaN),
Tuple.Create("Joe", Double.NaN),
Tuple.Create("Adam", 1.36),
Tuple.Create("Selena", 2.01),
Tuple.Create("Jake", 1.36) };
for (int ctr = 0; ctr < distancesWalked.Length; ctr++)
{
Tuple<string, double> distanceWalked = distancesWalked[ctr];
for (int ctr2 = ctr + 1; ctr2 < distancesWalked.Length; ctr2++)
{
Console.WriteLine("{0} = {1}: {2}", distanceWalked,
distancesWalked[ctr2],
((IStructuralEquatable)distanceWalked).Equals(distancesWalked[ctr2],
new Item2Comparer<string, double>()));
}
Console.WriteLine();
}
}
}
// The example displays the following output:
// (Jan, NaN) = (Joe, NaN): True
// (Jan, NaN) = (Adam, 1.36): False
// (Jan, NaN) = (Selena, 2.01): False
// (Jan, NaN) = (Jake, 1.36): False
//
// (Joe, NaN) = (Adam, 1.36): False
// (Joe, NaN) = (Selena, 2.01): False
// (Joe, NaN) = (Jake, 1.36): False
//
// (Adam, 1.36) = (Selena, 2.01): False
// (Adam, 1.36) = (Jake, 1.36): True
//
// (Selena, 2.01) = (Jake, 1.36): False
open System
open System.Collections
type Item2Comparer<'T1, 'T2 when 'T1: equality and 'T2: equality>() =
interface IEqualityComparer with
member _.GetHashCode(obj) =
match obj with
| :? 'T1 as obj->
obj.GetHashCode()
| _ ->
(obj :?> 'T2).GetHashCode()
member _.Equals(x, y) =
// Return true for all values of Item1.
match x with
| :? 'T1 ->
true
| _ ->
x.Equals y
let distancesWalked =
[| Tuple.Create("Jan", Double.NaN)
Tuple.Create("Joe", Double.NaN)
Tuple.Create("Adam", 1.36)
Tuple.Create("Selena", 2.01)
Tuple.Create("Jake", 1.36) |]
for ctr = 0 to distancesWalked.Length - 1 do
let distanceWalked = distancesWalked[ctr]
for ctr2 = ctr + 1 to distancesWalked.Length - 1 do
printfn $"{distanceWalked} = {distancesWalked[ctr2]}: {(distanceWalked :> IStructuralEquatable).Equals(distancesWalked[ctr2], Item2Comparer<string, double>())}"
printfn ""
// The example displays the following output:
// (Jan, NaN) = (Joe, NaN): True
// (Jan, NaN) = (Adam, 1.36): False
// (Jan, NaN) = (Selena, 2.01): False
// (Jan, NaN) = (Jake, 1.36): False
//
// (Joe, NaN) = (Adam, 1.36): False
// (Joe, NaN) = (Selena, 2.01): False
// (Joe, NaN) = (Jake, 1.36): False
//
// (Adam, 1.36) = (Selena, 2.01): False
// (Adam, 1.36) = (Jake, 1.36): True
//
// (Selena, 2.01) = (Jake, 1.36): False
Imports System.Collections
Public Class Item2Comparer(Of T1, T2) : Implements IEqualityComparer
Public Overloads Function Equals(x As Object, y As Object) As Boolean _
Implements IEqualityComparer.Equals
' Return true for all values of Item1.
If TypeOf x Is T1 Then
Return True
Else
Return x.Equals(y)
End If
End Function
Public Overloads Function GetHashCode(obj As Object) As Integer _
Implements IEqualityComparer.GetHashCode
If TypeOf obj Is T1 Then
Return CType(obj, T1).GetHashCode()
Else
Return CType(obj, T2).GetHashCode()
End If
End Function
End Class
Module Example
Public Sub Main()
Dim distancesWalked() = {
Tuple.Create("Jan", Double.NaN),
Tuple.Create("Joe", Double.NaN),
Tuple.Create("Adam", 1.36),
Tuple.Create("Selena", 2.01),
Tuple.Create("Jake", 1.36) }
For ctr As Integer = 0 To distancesWalked.Length - 1
Dim distanceWalked As Tuple(Of String, Double) = distancesWalked(ctr)
For ctr2 As Integer = ctr + 1 To distancesWalked.Length - 1
Console.WriteLine("{0} = {1}: {2}", distanceWalked,
distancesWalked(ctr2),
DirectCast(distanceWalked, IStructuralEquatable).Equals(distancesWalked(ctr2),
new Item2Comparer(Of String, Double)))
Next
Console.WriteLine()
Next
End Sub
End Module
' The example displays the following output:
' (Jan, NaN) = (Joe, NaN): True
' (Jan, NaN) = (Adam, 1.36): False
' (Jan, NaN) = (Selena, 2.01): False
' (Jan, NaN) = (Jake, 1.36): False
'
' (Joe, NaN) = (Adam, 1.36): False
' (Joe, NaN) = (Selena, 2.01): False
' (Joe, NaN) = (Jake, 1.36): False
'
' (Adam, 1.36) = (Selena, 2.01): False
' (Adam, 1.36) = (Jake, 1.36): True
'
' (Selena, 2.01) = (Jake, 1.36): False
備註
這個成員是明確介面成員實作， 只有在 Tuple<T1,T2> 執行個體轉換成 IStructuralEquatable 介面時，才能使用這個成員。
只有在 不是 null 時 other ，才會呼叫 實 IStructuralEquatable.Equals 作，如果它可以在 C#) 中成功轉換 ( (Tuple<T1,T2> ，或Visual Basic) 轉換成元件與目前實例類型相同的物件， 方法 IStructuralEquatable.Equals 會先傳遞 Item1 要與實作比較 IEqualityComparer.Equals 的物件 Tuple<T1,T2> 值。 如果這個方法呼叫傳 true 回 ，則會再次呼叫 方法，並傳遞 Item2 兩 Tuple<T1,T2> 個 物件的值。