CreateComparer

Definition

Namespace: Resto.Front.PrintTemplates.Cheques.Razor

IEqualityComparer<TObject> TemplateBase<T>.CreateComparer<TObject>(Func<TObject, TObject, bool> equals)

Definition

Namespace: Resto.Front.PrintTemplates.Cheques.Razor

Creates an equality comparer backed by an equality delegate and a constant hash code.

IEqualityComparer<TObject> TemplateBase<T>.CreateComparer<TObject>(Func<TObject, TObject, bool> equals)

Returns: IEqualityComparer<TObject>
Nullability: Not specified
Declared in: Resto.Front.PrintTemplates.Cheques.Razor.TemplateBase<T>
Model purpose: Base class for Legacy Razor print templates. Model contains the document data of type T. Provides formatting and markup output methods.

Parameters

Func<TObject, TObject, bool> equals: Equality function; must not be null. Receives the original operands, including null for reference types.

Type parameters

TObject: Type of objects to compare.

Return value

A new IEqualityComparer<TObject> that forwards calls to the supplied delegates.

Remarks

GetHashCode always returns 0, so the equality/hash contract is satisfied but hash collections can degrade to linear searches. For large Distinct, GroupBy or dictionary workloads, prefer the overload with a compatible hash function. Exceptions from equals propagate when comparison is performed.

Exceptions

System.ArgumentNullException: equals is null.

Example

var comparer = CreateComparer<string>(StringComparer.OrdinalIgnoreCase.Equals);
comparer.Equals("Tea", "TEA"); // true
comparer.GetHashCode("Tea"); // 0

Type arguments

TObject: No description is provided for this symbol.

IEqualityComparer<TObject> TemplateBase<T>.CreateComparer<TObject>(Func<TObject, TObject, bool> equals, Func<TObject, int> getHashCode)

Definition

Namespace: Resto.Front.PrintTemplates.Cheques.Razor

Creates an equality comparer backed by equality and hash-code delegates.

IEqualityComparer<TObject> TemplateBase<T>.CreateComparer<TObject>(Func<TObject, TObject, bool> equals, Func<TObject, int> getHashCode)

Returns: IEqualityComparer<TObject>
Nullability: Not specified
Declared in: Resto.Front.PrintTemplates.Cheques.Razor.TemplateBase<T>
Model purpose: Base class for Legacy Razor print templates. Model contains the document data of type T. Provides formatting and markup output methods.

Parameters

Func<TObject, TObject, bool> equals: Equality function; must not be null. Receives the original operands, including null for reference types.
Func<TObject, int> getHashCode: Hash-code function; must not be null and must return the same hash for equal objects.

Type parameters

TObject: Type of objects to compare.

Return value

A new IEqualityComparer<TObject> that forwards calls to the supplied delegates.

Remarks

Equality must be reflexive, symmetric and transitive, and compatible with the hash function. Delegates must handle null if callers can pass it. Delegate exceptions propagate when the comparer is used, not when it is created.

Exceptions

System.ArgumentNullException: equals or getHashCode is null.

Example

var comparer = CreateComparer<string>(StringComparer.OrdinalIgnoreCase.Equals,
    s => s == null ? 0 : StringComparer.OrdinalIgnoreCase.GetHashCode(s));
comparer.Equals("Tea", "TEA"); // true

Type arguments

TObject: No description is provided for this symbol.