private ExportCardinalityCheckResult TryGetExportsCore(ImportDefinition definition, AtomicComposition atomicComposition, out IEnumerable <Export> exports)
{
Assumes.NotNull(definition);
exports = GetExportsCore(definition, atomicComposition);
var checkResult = ExportServices.CheckCardinality(definition, exports);
// Export providers treat >1 match as zero for cardinality 0-1 imports
// If this policy is moved we need to revisit the assumption that the
// ImportEngine made during previewing the only required imports to
// now also preview optional imports.
if (checkResult == ExportCardinalityCheckResult.TooManyExports &&
definition.Cardinality == ImportCardinality.ZeroOrOne)
{
checkResult = ExportCardinalityCheckResult.Match;
exports = null;
}
if (exports == null)
{
exports = EmptyExports;
}
return(checkResult);
}
private static void EnsureCardinality(ImportDefinition definition, Export[] exports)
{
Requires.NullOrNotNullElements(exports, "exports");
ExportCardinalityCheckResult result = ExportServices.CheckCardinality(definition, exports);
switch (result)
{
case ExportCardinalityCheckResult.NoExports:
throw new ArgumentException(Strings.Argument_ExportsEmpty, "exports");
case ExportCardinalityCheckResult.TooManyExports:
throw new ArgumentException(Strings.Argument_ExportsTooMany, "exports");
default:
Assumes.IsTrue(result == ExportCardinalityCheckResult.Match);
break;
}
}
private static void EnsureCardinality(ImportDefinition definition, Export[] exports)
{
Requires.NullOrNotNullElements(exports, nameof(exports));
ExportCardinalityCheckResult result = ExportServices.CheckCardinality(definition, exports);
switch (result)
{
case ExportCardinalityCheckResult.NoExports:
throw new ArgumentException(SR.Argument_ExportsEmpty, nameof(exports));
case ExportCardinalityCheckResult.TooManyExports:
throw new ArgumentException(SR.Argument_ExportsTooMany, nameof(exports));
default:
if (result != ExportCardinalityCheckResult.Match)
{
throw new Exception(SR.Diagnostic_InternalExceptionMessage);
}
break;
}
}