Everyone that uses CRM 2011 must have come across Odata
service and might have used the Odata service for CRID operations. This works
very well. However there is a small thing that we ought to be keeping in our
mind when we are retrieving data using Odata service. That is it only returns the
first 50 records. If you want to work with more than that then you have to
change your Odata query.
There is a keyword that can be used. That is “top”. There is
a good article and samples given in the CRM SDK. We have changed this to accommodate
our needs.
We wanted to retrieve price list items whose start date is
greater than a particular date and keep that in generic list. The code which
was written has been pasted below.
private void
SearchPriceLevel()
{
DataServiceQuery<PriceLevel> query = (DataServiceQuery<PriceLevel>)context.PriceLevelSet.AddQueryOption("$top", 100).
Where(c => c.BeginDate <=
Convert.ToDateTime("12/12/2011"));
query.BeginExecute(ProcessPages<PriceLevel>, new
PagingContext<PriceLevel>()
{
ServiceContext = _context,
Query = query,
PageProcessor = delegate(DataServiceCollection<PriceLevel> results)
{
try
{
if (null == PriceLevelCollection)
{
PriceLevelCollection = new DataServiceCollection<PriceLevel>(_context);
PriceLevelCollection.Load(results);
}
else
{
for (int i = 0; i
< results.Count; i++)
{
PriceLevelCollection.Add(results[i]);
}
}
}
catch
(Exception ex)
{
}
return
true;
}
});
}
private void
ProcessPages(IAsyncResult result)
{
try
{
PagingContext
context = (PagingContext)result.AsyncState;
QueryOperationResponse
response;
if
(null == context.Query)
{
response = (QueryOperationResponse)context.ServiceContext.EndExecute(result);
}
else
{
response = (QueryOperationResponse)context.Query.EndExecute(result);
context.Query = null;
}
DataServiceCollection
results = new DataServiceCollection(response);
if
(results != null && results.Count >
0)
{
Type
typeParameterType = typeof(T);
if
(typeParameterType.Name.ToLower() == "pricelevel")
{
IEnumerable<PriceLevel>
priceLevelItems = results.Cast<PriceLevel>();
OnSearchPriceLevelCompleted(priceLevelItems);
}
}
if
(null != context.PageProcessor &&
!context.PageProcessor(results))
{
return;
}
DataServiceQueryContinuation
token = results.Continuation;
if
(null == token)
{
priceLevelViewModel.PriceLevels = priceLevelCollection;
if
(priceLevelViewModel.PriceLevels != null
&& priceLevelViewModel.PriceLevels.Count > 0)
{
SearchProductPriceLevel();
}
return;
}
context.ServiceContext.BeginExecute(token, ProcessPages,
context);
}
catch
(Exception ex)
{
throw
ex;
}
}
private
void OnSearchPriceLevelCompleted(IEnumerable<PriceLevel>
pl)
{
try
{
IEnumerator
enumer = ((IEnumerable)pl).GetEnumerator();
while
(enumer.MoveNext())
{
//This
is a Generic list which contains Pricelevel items and it’s declared as a class
variable
priceLevelCollection.Add((PriceLevel)enumer.Current);
}
}
catch
(Exception se)
{
}
}
sealed class
PagingContext
{
public DataServiceContext ServiceContext { get; set; }
public DataServiceQuery Query { get; set; }
public Func<DataServiceCollection,
bool> PageProcessor { get; set; }
}
You can find the code given for this from Microsoft at the
following location of the CRM 2011 SDK.
sdk\samplecode\cs\silverlight\restendpointpagingsilverlight
You can find more information about this from the following
links.
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