/// <summary>
/// Does the current iterator have another batch of data to process?
/// </summary>
/// <returns>true if more data can be accessed via <code>CurrentBatch</code></returns>
/// <remarks>
/// Creates a new database context, issues a query, and places a materialized collection in <code>CurrentBatch</code>.
/// Context is disposed once the query is issued.
/// Materialized collection is specified by <code>BuildIQueryable</code>. Use of any associated navigation properties
/// must be accounted for by using the appropriate <code>.Include</code> operator where the query is
/// built in <code>BuildIQueryable</code>.
/// </remarks>
public bool HasNext()
{
using (YourObjectContextHere db = new YourObjectContextHere())
{
this.currentBatch = this.BuildIQueryable(db)
.OrderBy(this.orderBy)
.Skip(this.currentIndex)
.Take(this.batchSize)
.ToList()
.AsParallel();
this.currentIndex += this.batchSize;
return(currentBatch.Count() > 0);
}
}
/// <summary> /// Given a Database Context, builds a query which can be executed in batches. /// </summary> /// <param name="db">context on which to build and execute the query</param> /// <returns>a query which will be executed and materialized</returns> /// <remarks>Context will be disposed as soon a HasNext has been executed.</remarks> protected abstract IQueryable <T> BuildIQueryable(YourObjectContextHere db);
protected override IQueryable<MyObject> BuildIQueryable(YourObjectContextHere db)
{
IQueryable<MyObject> myObjects= db.SomeCollection.Select(x => this.instanceIds.Contains(x).Include("SomethingImportant");
return myObjects;
}
