Terminal operations

Part of the OhData.Client guide. These methods execute a query built with the querying builders and materialise the result.

ToListAsync

Returns all matching items as a List<T>:

List<Product> items = await client.For<Product>()
    .Filter(x => x.Price > 5)
    .OrderBy(x => x.Name)
    .ToListAsync();

ToPageAsync

Returns items plus the total count (forces $count=true):

ODataPage<Product> page = await client.For<Product>()
    .OrderBy(x => x.Id)
    .Top(20).Skip(0)
    .ToPageAsync();

Console.WriteLine($"Page 1 of {Math.Ceiling((double)page.TotalCount! / 20)}");
foreach (var p in page.Items) { ... }

ODataPage<T> has:

• Items — the entities on this page
• TotalCount — total matching entities (pre-pagination), null if the server didn't return @odata.count
• NextLink — the URL to follow for the next page of results (server-driven pagination), null when there are no more pages

Server-driven pagination. When the server enforces a page size via MaxTop, it includes @odata.nextLink in the response. Inspect NextLink to determine whether more pages exist. To follow the link, issue a new request using the URL from NextLink directly (it is a fully-qualified absolute URL).

FirstOrDefaultAsync

Returns the first match or null. Applies $top=1 automatically:

Product? cheapest = await client.For<Product>()
    .OrderBy(x => x.Price)
    .FirstOrDefaultAsync();

CountAsync

Hits GET /{EntitySet}/$count - returns the total count as a long:

long count = await client.For<Product>()
    .Filter(x => x.Price < 5)
    .CountAsync();

AnyAsync

Returns true if at least one entity matches:

bool hasStock = await client.For<Product>()
    .Filter(x => x.StockLevel > 0)
    .AnyAsync();

FirstAsync

Returns the first match. Applies $top=1 automatically. Throws InvalidOperationException when the collection is empty (use FirstOrDefaultAsync if no results is a valid outcome):

Product cheapest = await client.For<Product>()
    .OrderBy(x => x.Price)
    .FirstAsync();

SingleOrDefaultAsync

Returns the single matching entity, or null when none match. Applies $top=2 and throws InvalidOperationException when more than one entity matches:

Product? active = await client.For<Product>()
    .Filter(x => x.Sku == "ABC-1")
    .SingleOrDefaultAsync();

SingleAsync

Returns the single matching entity. Throws InvalidOperationException when zero or more than one entity matches:

Product product = await client.For<Product>()
    .Filter(x => x.Sku == "ABC-1")
    .SingleAsync();

ToArrayAsync

Returns all matching items as a T[]:

Product[] items = await client.For<Product>()
    .Filter(x => x.IsActive)
    .ToArrayAsync();

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Next: Single-entity operations →