Method Case

Case<TValue, TResult>(Func<TValue>, IDictionary<TValue, IAsyncEnumerable<TResult>>)

Returns a sequence from a dictionary based on the result of evaluating a selector function.

Declaration

public static IAsyncEnumerable<TResult> Case<TValue, TResult>(Func<TValue> selector, IDictionary<TValue, IAsyncEnumerable<TResult>> sources) where TValue : notnull

Parameters

Type	Name	Description
Func<TValue>	selector	Selector function used to pick a sequence from the given sources.
IDictionary<TValue, IAsyncEnumerable<TResult>>	sources	Dictionary mapping selector values onto resulting sequences.

Returns

Type	Description
IAsyncEnumerable<TResult>	The source sequence corresponding with the evaluated selector value; otherwise, an empty sequence.

Type Parameters

Name	Description
TValue	Type of the selector value.
TResult	Result sequence element type.

Remarks

selector is not evaluated until enumeration. The value returned will be used to select a sequence from sources; enumeration will continue with items from that sequence.

If the value returned by selector is not present in sources, the resulting sequence will be empty.

Exceptions

Type	Condition
ArgumentNullException	selector or sources is null.

Case<TValue, TResult>(Func<ValueTask<TValue>>, IDictionary<TValue, IAsyncEnumerable<TResult>>)

Returns a sequence from a dictionary based on the result of evaluating a selector function.

Declaration

public static IAsyncEnumerable<TResult> Case<TValue, TResult>(Func<ValueTask<TValue>> selector, IDictionary<TValue, IAsyncEnumerable<TResult>> sources) where TValue : notnull

Parameters

Type	Name	Description
Func<ValueTask<TValue>>	selector	Selector function used to pick a sequence from the given sources.
IDictionary<TValue, IAsyncEnumerable<TResult>>	sources	Dictionary mapping selector values onto resulting sequences.

Returns

Type	Description
IAsyncEnumerable<TResult>	The source sequence corresponding with the evaluated selector value; otherwise, an empty sequence.

Type Parameters

Name	Description
TValue	Type of the selector value.
TResult	Result sequence element type.

Remarks

selector is not evaluated until enumeration. The value returned will be used to select a sequence from sources; enumeration will continue with items from that sequence.

If the value returned by selector is not present in sources, the resulting sequence will be empty.

Exceptions

Type	Condition
ArgumentNullException	selector or sources is null.

Case<TValue, TResult>(Func<TValue>, IDictionary<TValue, IAsyncEnumerable<TResult>>, IAsyncEnumerable<TResult>)

Returns a sequence from a dictionary based on the result of evaluating a selector function.

Declaration

public static IAsyncEnumerable<TResult> Case<TValue, TResult>(Func<TValue> selector, IDictionary<TValue, IAsyncEnumerable<TResult>> sources, IAsyncEnumerable<TResult> defaultSource) where TValue : notnull

Parameters

Type	Name	Description
Func<TValue>	selector	Selector function used to pick a sequence from the given sources.
IDictionary<TValue, IAsyncEnumerable<TResult>>	sources	Dictionary mapping selector values onto resulting sequences.
IAsyncEnumerable<TResult>	defaultSource	Default sequence to return in case there's no corresponding source for the computed selector value.

Returns

Type	Description
IAsyncEnumerable<TResult>	The source sequence corresponding with the evaluated selector value; otherwise, an empty sequence.

Type Parameters

Name	Description
TValue	Type of the selector value.
TResult	Result sequence element type.

Remarks

selector is not evaluated until enumeration. The value returned will be used to select a sequence from sources; enumeration will continue with items from that sequence.

Exceptions

Type	Condition
ArgumentNullException	selector, sources, or defaultSource is null.

Case<TValue, TResult>(Func<ValueTask<TValue>>, IDictionary<TValue, IAsyncEnumerable<TResult>>, IAsyncEnumerable<TResult>)

Returns a sequence from a dictionary based on the result of evaluating a selector function.

Declaration

public static IAsyncEnumerable<TResult> Case<TValue, TResult>(Func<ValueTask<TValue>> selector, IDictionary<TValue, IAsyncEnumerable<TResult>> sources, IAsyncEnumerable<TResult> defaultSource) where TValue : notnull

Parameters

Type	Name	Description
Func<ValueTask<TValue>>	selector	Selector function used to pick a sequence from the given sources.
IDictionary<TValue, IAsyncEnumerable<TResult>>	sources	Dictionary mapping selector values onto resulting sequences.
IAsyncEnumerable<TResult>	defaultSource	Default sequence to return in case there's no corresponding source for the computed selector value.

Returns

Type	Description
IAsyncEnumerable<TResult>	The source sequence corresponding with the evaluated selector value; otherwise, an empty sequence.

Type Parameters

Name	Description
TValue	Type of the selector value.
TResult	Result sequence element type.

Remarks

selector is not evaluated until enumeration. The value returned will be used to select a sequence from sources; enumeration will continue with items from that sequence.

Exceptions

Type	Condition
ArgumentNullException	selector, sources, or defaultSource is null.