/// <summary>
/// Batches a <b>Select query</b> for the <b>OData</b> entity.
/// </summary>
/// <typeparam name="T">The entity <see cref="Type"/>.</typeparam>
/// <param name="query">The <see cref="ODataQueryable{T}"/>.</param>
/// <returns>The <see cref="ODataBatchItem"/>.</returns>
public async Task <ODataBatchItem> SelectQueryAsync <T>(IQueryable <T> query)
{
if (query == null)
{
throw new ArgumentNullException(nameof(query));
}
if (!(query is ODataQueryable <T> q))
{
throw new ArgumentException("The query must be an instance of ODataQueryable<T>.", nameof(query));
}
if (q.QueryExecutor.OData != this.OData)
{
throw new ArgumentException("The query can only be invoked by this batch where both the batch and query are created by the same ODataBase instance.");
}
var qa = q.QueryExecutor.GetQueryAggregator(q.Expression, null);
var queryArgs = q.QueryExecutor.QueryArgs;
var obi = AddRequest(await OData.BuildQueryRequestAsync(queryArgs, q.GetODataQuery(null)).ConfigureAwait(false));
obi.GetValueFunc = async() =>
{
var coll = new List <T>();
await OData.ProcessQueryResponse(obi.ResponseMessage, queryArgs, qa, coll).ConfigureAwait(false);
return(coll);
};
return(obi);
}
/// <summary>
/// Creates (<see cref="ODataBase.CreateQuery{T}(ODataArgs)"/>) and batches a <b>Select query</b> for the <b>OData</b> entity.
/// </summary>
/// <typeparam name="TColl">The collection <see cref="Type"/>.</typeparam>
/// <typeparam name="T">The entity <see cref="Type"/>.</typeparam>
/// <param name="queryArgs">The <see cref="ODataArgs"/>.</param>
/// <param name="query">An optional function to enable in-place query selection.</param>
/// <returns>The <see cref="ODataBatchItem"/>.</returns>
public async Task <ODataBatchItem> SelectQueryAsync <TColl, T>(ODataArgs queryArgs, Func <IQueryable <T>, IQueryable <T> > query = null) where TColl : ICollection <T>, new() where T : class
{
var q = OData.CreateQuery <T>(queryArgs);
if (query != null)
{
var q2 = query(q) as ODataQueryable <T>;
q = q2 ?? throw new InvalidOperationException("The query function must return an instance of ODataQueryable<T>.");
}
var qa = q.QueryExecutor.GetQueryAggregator(q.Expression, null);
var obi = AddRequest(await OData.BuildQueryRequestAsync(queryArgs, qa.ToString()).ConfigureAwait(false));
obi.GetValueFunc = async() =>
{
var coll = new TColl();
await OData.ProcessQueryResponse(obi.ResponseMessage, queryArgs, qa, coll).ConfigureAwait(false);
return(coll);
};
return(obi);
}
