Table of Contents

Class PartialObjectResult

Namespace
FunctionalDdd
Assembly
FunctionalDdd.Asp.dll

Represents an ObjectResult that returns HTTP 206 Partial Content with a Content-Range header. Used to indicate that the response contains a subset of the requested resource.

public class PartialObjectResult : ObjectResult, IStatusCodeActionResult, IActionResult
Inheritance
PartialObjectResult
Implements
Inherited Members
Extension Methods

Examples

Using PartialObjectResult directly in a controller:

[HttpGet]
public IActionResult GetUsers([FromQuery] int page = 0, [FromQuery] int pageSize = 25)
{
    var from = page * pageSize;
    var to = from + pageSize - 1;
    var totalCount = _userRepository.Count();
    var users = _userRepository.GetRange(from, pageSize);

    if (to >= totalCount - 1)
    {
        // Complete result - return 200 OK
        return Ok(users);
    }

    // Partial result - return 206 Partial Content
    return new PartialObjectResult(from, to, totalCount, users);
}

// Response headers:
// HTTP/1.1 206 Partial Content
// Content-Range: items 0-24/100

Using with ActionResultExtensions (recommended approach):

[HttpGet]
public ActionResult<IEnumerable<UserDto>> GetUsers(
    [FromQuery] int page = 0,
    [FromQuery] int pageSize = 25)
{
    var from = page * pageSize;
    var to = from + pageSize - 1;

    return _userService
        .GetPagedUsers(from, pageSize)
        .Map(result => (result.Users, result.TotalCount))
        .Map(x => x.Users)
        .ToActionResult(this, from, to, totalCount);

    // Automatically returns PartialObjectResult when appropriate
}

Remarks

This class implements the HTTP 206 Partial Content response as defined in RFC 7233. It's commonly used for:

  • Paginated API responses
  • Range requests for large datasets
  • Incremental data loading in client applications
  • Resumable downloads or data transfers

The Content-Range header format is: {unit} {from}-{to}/{total} Content-Range: items 0-24/100

This class is typically used by ToActionResult<TValue>(Result<TValue>, ControllerBase, long, long, long) and should rarely be instantiated directly in controller code.

Constructors

PartialObjectResult(long, long, long?, object?)

Initializes a new instance of the PartialObjectResult class with explicit range values.

public PartialObjectResult(long rangeStart, long rangeEnd, long? totalLength, object? value)

Parameters

rangeStart long

The starting index of the range (zero-indexed, inclusive).

rangeEnd long

The ending index of the range (zero-indexed, inclusive).

totalLength long?

The total number of items available, or null if unknown.

value object

The partial data to include in the response body.

Examples

// Return items 0-24 out of 100 total
return new PartialObjectResult(0, 24, 100, users);
// Content-Range: items 0-24/100

// Return items 25-49, total unknown
return new PartialObjectResult(25, 49, null, users);
// Content-Range: items 25-49/*

Remarks

The range is inclusive on both ends: [rangeStart, rangeEnd]. For example, to return items 0-24 of 100: rangeStart=0, rangeEnd=24, totalLength=100.

The Content-Range header will be set to: items {rangeStart}-{rangeEnd}/{totalLength} If totalLength is null, it will be formatted as: items {rangeStart}-{rangeEnd}/*

The unit "items" is used by default and is suitable for most paginated API responses. For byte-range requests (e.g., file downloads), use the constructor that accepts ContentRangeHeaderValue directly.

PartialObjectResult(ContentRangeHeaderValue, object?)

Initializes a new instance of the PartialObjectResult class with a pre-configured ContentRangeHeaderValue.

public PartialObjectResult(ContentRangeHeaderValue contentRangeHeaderValue, object? value)

Parameters

contentRangeHeaderValue ContentRangeHeaderValue

The Content-Range header value to use in the response.

value object

The partial data to include in the response body.

Examples

Using with byte ranges for file downloads:

var contentRange = new ContentRangeHeaderValue(0, 1023, 2048)
{
    Unit = "bytes"
};
return new PartialObjectResult(contentRange, fileBytes);
// Content-Range: bytes 0-1023/2048

Using with a domain model that includes range information:

var pagedResult = await _repository.GetPagedAsync(page, pageSize);
var contentRange = new ContentRangeHeaderValue(
    pagedResult.From,
    pagedResult.To,
    pagedResult.TotalCount)
{
    Unit = "items"
};
return new PartialObjectResult(contentRange, pagedResult.Items);

Remarks

This constructor allows full control over the Content-Range header, including:

  • Custom unit values (e.g., "bytes" for file downloads, "items" for collections)
  • Pre-computed range values from domain models
  • Complex range scenarios not covered by the simpler constructor

Use this constructor when you need to specify a unit other than "items", or when the Content-Range information is already available as a ContentRangeHeaderValue.

Properties

ContentRangeHeaderValue

Gets the Content-Range header value that will be included in the response.

public ContentRangeHeaderValue ContentRangeHeaderValue { get; }

Property Value

ContentRangeHeaderValue

The ContentRangeHeaderValue containing range and total length information.

Remarks

This property can be used to inspect the range information before the response is sent, for example in middleware or filters.

Methods

OnFormatting(ActionContext)

Called during the formatting of the action result to add the Content-Range header to the HTTP response.

public override void OnFormatting(ActionContext context)

Parameters

context ActionContext

The action context containing the HTTP context and response.

Remarks

This method is called by the ASP.NET Core framework as part of the response formatting pipeline. It adds the Content-Range header to the response headers before the response is sent to the client.

The Content-Range header format follows RFC 7233: Content-Range: {unit} {from}-{to}/{total}

You should not need to call this method directly; it's invoked automatically by the framework.

Exceptions

ArgumentNullException

Thrown if context is null.

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