52 lines
1.6 KiB
Plaintext
52 lines
1.6 KiB
Plaintext
When you implement ``++IComparable++`` or ``++IComparable<T>++`` on a class you should also override ``++Equals(object)++`` and overload the comparison operators (``++==++``, ``++!=++``, ``++<++``, ``++<=++``, ``++>++``, ``++>=++``). That's because the CLR cannot automatically call your ``++CompareTo++`` implementation from ``++Equals(object)++`` or from the base comparison operator implementations. Additionally, it is best practice to override ``++GetHashCode++`` along with ``++Equals++``.
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This rule raises an issue when a class implements ``++IComparable++`` without also overriding ``++Equals(object)++`` and the comparison operators.
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== Noncompliant Code Example
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----
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public class Foo: IComparable // Noncompliant
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{
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public int CompareTo(object obj) { /* ... */ }
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}
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----
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== Compliant Solution
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----
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public class Foo: IComparable
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{
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public int CompareTo(object obj) { /* ... */ }
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public override bool Equals(object obj)
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{
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var other = obj as Foo;
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if (object.ReferenceEquals(other, null))
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{
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return false;
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}
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return this.CompareTo(other) == 0;
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}
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public int GetHashCode() { /* ... */ }
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public static bool operator == (Foo left, Foo right)
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{
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if (object.ReferenceEquals(left, null))
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{
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return object.ReferenceEquals(right, null);
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}
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return left.Equals(right);
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}
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public static bool operator > (Foo left, Foo right)
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{
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return Compare(left, right) > 0;
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}
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public static bool operator < (Foo left, Foo right)
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{
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return Compare(left, right) < 0;
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}
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public static bool operator != (Foo left, Foo right)
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{
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return !(left == right);
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}
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}
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----
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