ValueType.Equals(Object) Method
Definition
Important
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Indicates whether this instance and a specified object are equal.
public:
override bool Equals(System::Object ^ obj);public override bool Equals (object obj);public override bool Equals (object? obj);override this.Equals : obj -> boolPublic Overrides Function Equals (obj As Object) As BooleanParameters
- obj
- Object
The object to compare with the current instance.
Returns
true if obj and this instance are the same type and represent the same value; otherwise, false.
Examples
The following example demonstrates how the Equals method can be overridden by a derived value type.
public ref struct Complex
{
public:
double m_Re;
double m_Im;
virtual bool Equals( Object^ ob ) override
{
if ( dynamic_cast<Complex^>(ob) )
{
Complex^ c = dynamic_cast<Complex^>(ob);
return m_Re == c->m_Re && m_Im == c->m_Im;
}
else
{
return false;
}
}
virtual int GetHashCode() override
{
return m_Re.GetHashCode() ^ m_Im.GetHashCode();
}
};
public struct Complex
{
public double m_Re;
public double m_Im;
public override bool Equals( object ob ){
if( ob is Complex ) {
Complex c = (Complex) ob;
return m_Re==c.m_Re && m_Im==c.m_Im;
}
else {
return false;
}
}
public override int GetHashCode(){
return m_Re.GetHashCode() ^ m_Im.GetHashCode();
}
}
type Complex() =
member val m_Re = 0. with get, set
member val m_Im = 0. with get, set
override this.Equals(ob) =
match ob with
| :? Complex as c ->
this.m_Re = c.m_Re && this.m_Im = c.m_Im
| _ -> false
override this.GetHashCode() =
this.m_Re.GetHashCode() ^^^ this.m_Im.GetHashCode()
Public Structure Complex
Private m_Re As Double
Private m_Im As Double
Public Overloads Function Equals(ob As Object) As Boolean
If TypeOf ob Is Complex Then
Dim c As Complex = CType(ob, Complex)
Return m_Re = c.m_Re And m_Im = c.m_Im
Else
Return False
End If
End Function
Public Overloads Function GetHashCode() As Integer
Return m_Re.GetHashCode() ^ m_Im.GetHashCode()
End Function
End Structure
Remarks
The ValueType.Equals(Object) method overrides Object.Equals(Object) and provides the default implementation of value equality for all value types in .NET.
The default implementation calls Object.Equals(Object) on each field of the current instance and obj and returns true if all fields are equal.
.NET 9 and later, the default implementation of ValueType.Equals(Object) throws NotSupportedException if InlineArrayAttribute is applied to the type.
Important
Particularly if your value type contains fields that are reference types, you should override the Equals(Object) method. This can improve performance and enable you to more closely represent the meaning of equality for the type.
Notes for the Windows Runtime
When you call the Equals method on a Windows Runtime structure, it provides the default behavior for value types that don't override Equals. This is part of the support that .NET provides for the Windows Runtime (see .NET Support for Windows Store Apps and Windows Runtime). Windows Runtime structures can't override Equals, even if they're written with C# or Visual Basic, because they can't have methods. (In addition, structures in the Windows Runtime itself don't inherit ValueType.) However, they appear to have ToString, Equals, and GetHashCode methods when you use them in your C# or Visual Basic code, and .NET provides the default behavior for these methods.
