Form Collection Handling

According to OpenAPI specification, collections in URI query or form fields support 5 representation formats:

Format	Description
Csv	Comma-separated
Ssv	Space-separated
Tsv	Backslash-separated
Pipes	Pipe-separated
Multi	Multiple key-value pairs with the same name

Example

For an array value like id = ["001", "002"], when processed by PathQueryAttribute or FormContentAttribute:

CollectionFormat	Data
[PathQuery(CollectionFormat = CollectionFormat.Csv)]	id=001,002
[PathQuery(CollectionFormat = CollectionFormat.Ssv)]	id=001 002
[PathQuery(CollectionFormat = CollectionFormat.Tsv)]	id=001\002
[PathQuery(CollectionFormat = CollectionFormat.Pipes)]	id=001|002
[PathQuery(CollectionFormat = CollectionFormat.Multi)]	id=001&id=002

Usage Example

public interface IUserApi
{
    [HttpGet("api/users")]
    Task<List<User>> GetAsync(
        [PathQuery(CollectionFormat = CollectionFormat.Multi)] int[] ids);
}

Resulting request: api/users?ids=1&ids=2&ids=3