public void FirstStartThrows()
{
Assert.ThrowsArgumentNull(() => { HttpContentCollectionExtensions.FirstStart(null, "A"); }, "contents");
IEnumerable <HttpContent> content = HttpContentCollectionExtensionsTests.CreateContent();
Assert.ThrowsArgumentNull(() => { HttpContentCollectionExtensions.FirstStart(content, null); }, "start");
foreach (string empty in TestData.EmptyStrings)
{
Assert.ThrowsArgumentNull(() => { HttpContentCollectionExtensions.FirstStart(content, empty); }, "start");
}
}
/// <summary>
/// Returns the first <see cref="HttpContent"/> in a sequence that has a <see cref="ContentDispositionHeaderValue"/> header field
/// parameter equal to <paramref name="start"/>. This parameter is typically used in connection with <c>multipart/related</c>
/// content (see RFC 2387).
/// </summary>
/// <param name="contents">The contents to evaluate.</param>
/// <param name="start">The start value to look for. A match is found if a <see cref="HttpContent"/> has a <c>Content-ID</c>
/// header field with the given value.</param>
/// <returns>null if source is empty or if no element matches; otherwise the first <see cref="HttpContent"/> in
/// the sequence with a matching value.</returns>
public static HttpContent FirstStartOrDefault(this IEnumerable <HttpContent> contents, string start)
{
if (contents == null)
{
throw new ArgumentNullException("contents");
}
if (String.IsNullOrWhiteSpace(start))
{
throw new ArgumentNullException("start");
}
return(contents.FirstOrDefault((item) =>
{
return HttpContentCollectionExtensions.FirstStart(item, start);
}));
}