Class SingleResultOpt

Facilities to manipulate single result options.

Inheritance

Object

SingleResultOpt

Inherited Members

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: Hgk.Zero.Options

Assembly: Hgk.Zero.Options.dll

Syntax

public static class SingleResultOpt

Methods

DefaultIfMoreThanOne<TSource>(ISingleResultOpt<TSource>)

Converts a single result option to another option, substituting a full option containing the default value of the contained type if this option represents more than one result.

Declaration

public static IOpt<TSource> DefaultIfMoreThanOne<TSource>(this ISingleResultOpt<TSource> source)

Parameters

Type	Name	Description
ISingleResultOpt<TSource>	source	A source single result option.

Returns

Type	Description
IOpt<TSource>	An option equivalent to source, if it represents a result of zero or one element; otherwise, an option containing the default value of TSource.

Type Parameters

Name	Description
TSource	The element type of source.

Exceptions

Type	Condition
ArgumentNullException	source is null.

DefaultIfMoreThanOne<TSource>(ISingleResultOpt<TSource>, TSource)

Converts a single result option to another option, substituting a full option containing the specified default value if this option represents more than one result.

Declaration

public static IOpt<TSource> DefaultIfMoreThanOne<TSource>(this ISingleResultOpt<TSource> source, TSource defaultValue)

Parameters

Type	Name	Description
ISingleResultOpt<TSource>	source	A source single result option.
TSource	defaultValue	The value to be contained by the returned option if source represents more than one result.

Returns

Type	Description
IOpt<TSource>	An option equivalent to source, if it represents a result of zero or one element; otherwise, an option containing defaultValue.

Type Parameters

Name	Description
TSource	The element type of source.

Exceptions

Type	Condition
ArgumentNullException	source is null.

EmptyIfMoreThanOne<TSource>(ISingleResultOpt<TSource>)

Converts a single result option to another option, substituting an empty option if this option represents more than one result.

Declaration

public static IOpt<TSource> EmptyIfMoreThanOne<TSource>(this ISingleResultOpt<TSource> source)

Parameters

Type	Name	Description
ISingleResultOpt<TSource>	source	A source single result option.

Returns

Type	Description
IOpt<TSource>	An option equivalent to source, if it represents a result of zero or one element; otherwise, an empty option.

Type Parameters

Name	Description
TSource	The element type of source.

Exceptions

Type	Condition
ArgumentNullException	source is null.

ForceSingleResultOpt(ISingleResultOpt)

Immediately computes the result of any deferred computation represented by a single result option and returns a new single result option representing the final result.

Declaration

public static ISingleResultOpt ForceSingleResultOpt(this ISingleResultOpt source)

Parameters

Type	Name	Description
ISingleResultOpt	source	A source single result option.

Returns

Type	Description
ISingleResultOpt	A single result option representing the final result of any deferred computation represented by source.

Exceptions

Type	Condition
ArgumentNullException	source is null.

ForceSingleResultOpt<TSource>(ISingleResultOpt<TSource>)

Immediately computes the result of any deferred computation represented by a single result option and returns a new single result option representing the final result.

Declaration

public static ISingleResultOpt<TSource> ForceSingleResultOpt<TSource>(this ISingleResultOpt<TSource> source)

Parameters

Type	Name	Description
ISingleResultOpt<TSource>	source	A source single result option.

Returns

Type	Description
ISingleResultOpt<TSource>	A single result option representing the final result of any deferred computation represented by source.

Type Parameters

Name	Description
TSource	The element type of source.

Exceptions

Type	Condition
ArgumentNullException	source is null.

Match<TSource, TResult>(ISingleResultOpt<TSource>, Func<TResult>, Func<TSource, TResult>, Func<TResult>)

Converts a single result option to another value based on its contents.

Declaration

public static TResult Match<TSource, TResult>(this ISingleResultOpt<TSource> source, Func<TResult> ifZero = null, Func<TSource, TResult> ifOne = null, Func<TResult> ifMoreThanOne = null)

Parameters

Type	Name	Description
ISingleResultOpt<TSource>	source	A source single result option.
Func<TResult>	ifZero	A function to produce the result if source represents a result of zero elements.
Func<TSource, TResult>	ifOne	A function to produce the result if source represents a result of one element, which accepts that element as a parameter.
Func<TResult>	ifMoreThanOne	A function to produce the result if source represents a result of more than one element.

Returns

Type	Description
TResult	The result of calling ifZero, ifOne, or ifMoreThanOne if source represents a result of zero, one, or more than one element, respectively.

Type Parameters

Name	Description
TSource	The element type of source.
TResult	The type of the result of this conversion.

Exceptions

Type	Condition
ArgumentNullException	source is null.
InvalidOperationException	ifZero is null and source represents a result of zero elements, or ifOne is null and source represents a result of one element, or ifMoreThanOne is null and source represents a result of more than one element.

MatchOpt<TSource, TResult>(ISingleResultOpt<TSource>, Func<Opt<TResult>>, Func<TSource, Opt<TResult>>, Func<Opt<TResult>>)

Converts a single result option to another option based on its contents.

Declaration

public static IOpt<TResult> MatchOpt<TSource, TResult>(this ISingleResultOpt<TSource> source, Func<Opt<TResult>> ifZero = null, Func<TSource, Opt<TResult>> ifOne = null, Func<Opt<TResult>> ifMoreThanOne = null)

Parameters

Type	Name	Description
ISingleResultOpt<TSource>	source	A source single result option.
Func<Opt<TResult>>	ifZero	A function to produce the result if source represents a result of zero elements.
Func<TSource, Opt<TResult>>	ifOne	A function to produce the result if source represents a result of one element, which accepts that element as a parameter.
Func<Opt<TResult>>	ifMoreThanOne	A function to produce the result if source represents a result of more than one element.

Returns

Type	Description
IOpt<TResult>	An option equivalent to the result of calling ifZero, ifOne, or ifMoreThanOne if source represents a result of zero, one, or more than one element, respectively.

Type Parameters

Name	Description
TSource	The element type of source.
TResult	The element type of the result option for this conversion.

Remarks

This method is implemented using deferred execution; the query represented by this method is not performed until the contents of the returned option are resolved, such as by enumeration.

Exceptions

Type	Condition
ArgumentNullException	source is null.
InvalidOperationException	ifZero is null and source represents a result of zero elements, or ifOne is null and source represents a result of one element, or ifMoreThanOne is null and source represents a result of more than one element.

ReplaceIfMoreThanOne<TSource>(ISingleResultOpt<TSource>, IOpt<TSource>)

Converts a single result option to another option, substituting a specified option if this option represents more than one result.

Declaration

public static IOpt<TSource> ReplaceIfMoreThanOne<TSource>(this ISingleResultOpt<TSource> source, IOpt<TSource> replacement)

Parameters

Type	Name	Description
ISingleResultOpt<TSource>	source	A source single result option.
IOpt<TSource>	replacement	An option to produce the result if source represents a result of more than one element.

Returns

Type	Description
IOpt<TSource>	An option equivalent to source, if it represents a result of zero or one element; otherwise, an option equivalent to replacement.

Type Parameters

Name	Description
TSource	The element type of source.

Exceptions

Type	Condition
ArgumentNullException	source or replacement is null.

ReplaceIfMoreThanOne<TSource>(ISingleResultOpt<TSource>, Func<IOpt<TSource>>)

Converts a single result option to another option, substituting the result of a callback if this option represents more than one result.

Declaration

public static IOpt<TSource> ReplaceIfMoreThanOne<TSource>(this ISingleResultOpt<TSource> source, Func<IOpt<TSource>> replacementFactory)

Parameters

Type	Name	Description
ISingleResultOpt<TSource>	source	A source single result option.
Func<IOpt<TSource>>	replacementFactory	A function to produce the result if source represents a result of more than one element.

Returns

Type	Description
IOpt<TSource>	An option equivalent to source, if it represents a result of zero or one element; otherwise, an option equivalent to the result of calling replacementFactory.

Type Parameters

Name	Description
TSource	The element type of source.

Exceptions

Type	Condition
ArgumentNullException	source or replacementFactory is null.

See Also

ISingleResultOpt

ISingleResultOpt<T>

WhereSingle<TSource>(IEnumerable<TSource>)

WhereSingle<TSource>(IEnumerable<TSource>, Func<TSource, Boolean>)