/// <summary>
/// Generate a new type for the aggregated results and return an instance of the results with the aggregated value.
/// </summary>
/// <param name="dataToProject">The results to project.</param>
/// <param name="alias">The name of the alias to use in the new type.</param>
/// <param name="aliasType">The type of the alias to use in the new type.</param>
/// <returns>An instance of the results with the aggregated value as <see cref="IQueryable"/>.</returns>
private IQueryable ProjectResult(object dataToProject, string alias, Type aliasType)
{
var properties = new List <Tuple <Type, string> >()
{
new Tuple <Type, string>(aliasType, alias)
};
var resType = AggregationTypesGenerator.CreateType(properties.Distinct(new TypeStringTupleComapere()).ToList(), Context, true);
var objToProject = Activator.CreateInstance(resType);
var pi = resType.GetProperty(alias);
pi.SetValue(objToProject, dataToProject);
var dataToProjectList = (new List <object>()
{
objToProject
}).AsQueryable();
return(ExpressionHelpers.Cast(resType, dataToProjectList));
}
/// <summary>
/// Get the type to use for returning aggregation results in a group-by query.
/// </summary>
/// <param name="groupByTrasformation">The group by transformation.</param>
/// <param name="keyType">The type of a group by key.</param>
/// <returns>The new dynamic type.</returns>
private Type GetAggregationResultProjectionType(ApplyGroupbyClause groupByTrasformation, Type keyType)
{
if (groupByTrasformation.Aggregate == null)
{
throw new ArgumentException("group by without aggregate");
}
var keyProperties = new List <Tuple <Type, string> >();
var aggregationImplementation = AggregationImplementations <AggregationImplementationBase> .GetAggregationImplementation(groupByTrasformation.Aggregate.AggregationMethod);
var aliasType = aggregationImplementation.GetResultType(Context.ElementClrType, groupByTrasformation.Aggregate);
keyProperties.Add(new Tuple <Type, string>(aliasType, groupByTrasformation.Aggregate.Alias));
foreach (var prop in keyType.GetProperties())
{
if (prop.Name == "ComparerInstance")
{
continue;
}
keyProperties.Add(new Tuple <Type, string>(prop.PropertyType, prop.Name));
}
return(AggregationTypesGenerator.CreateType(keyProperties.Distinct(new TypeStringTupleComapere()).ToList(), Context, true));
}