// Create new project
System::SharedPtr<Project> project = System::MakeObject<Project>(dataDir + u"Blank2010.mpp");
    
// Assign resource "1 TRG: Trade Group" to the "TASK 1" by creating a ResourceAssignment object.
System::SharedPtr<Resource> resource = project->get_Resources()->GetById(1);
System::SharedPtr<Task> task = project->get_RootTask()->get_Children()->GetById(1);
    
System::SharedPtr<ResourceAssignment> assignment = project->get_ResourceAssignments()->Add(task, resource);
    
// Create custom attribute definition with lookup.
System::SharedPtr<ExtendedAttributeDefinition> resCostAttr = ExtendedAttributeDefinition::CreateLookupResourceDefinition(Aspose::Tasks::CustomFieldType::Cost, Aspose::Tasks::ExtendedAttributeResource::Cost5, u"My lookup resource cost");
project->get_ExtendedAttributes()->Add(resCostAttr);
    
auto value1 = [&]{ auto tmp_0 = System::MakeObject<Value>(); tmp_0->set_NumericValue(1500); tmp_0->set_Description(u"Val 1"); tmp_0->set_Id(1); tmp_0->set_Val(u"1500"); return tmp_0; }();
    
resCostAttr->AddLookupValue(value1);
    
resCostAttr->AddLookupValue([&]{ auto tmp_1 = System::MakeObject<Value>(); tmp_1->set_NumericValue(2500); tmp_1->set_Description(u"Val 2"); tmp_1->set_Id(2); return tmp_1; }());
    
// This value can be seen in "Resource usage" view of MS Project.
auto attributeValue = resCostAttr->CreateExtendedAttribute(value1);
assignment->get_ExtendedAttributes()->Add(attributeValue);
    
// Create custom attribute definition with lookup.
System::SharedPtr<ExtendedAttributeDefinition> taskCostAttr = ExtendedAttributeDefinition::CreateLookupTaskDefinition(Aspose::Tasks::ExtendedAttributeTask::Cost4, u"My lookup task cost");
    
project->get_ExtendedAttributes()->Add(taskCostAttr);
    
auto taskLookupValue1 = [&]{ auto tmp_2 = System::MakeObject<Value>(); tmp_2->set_NumericValue(18); tmp_2->set_Description(u"Task val 1"); tmp_2->set_Id(3); tmp_2->set_Val(u"18"); return tmp_2; }();
taskCostAttr->AddLookupValue(taskLookupValue1);
    
resCostAttr->AddLookupValue([&]{ auto tmp_3 = System::MakeObject<Value>(); tmp_3->set_NumericValue(30); tmp_3->set_Description(u"Task val 2"); tmp_3->set_Id(4); return tmp_3; }());
    
// This value can be seen in "Task usage" view of MS Project.
assignment->get_ExtendedAttributes()->Add(taskCostAttr->CreateExtendedAttribute(taskLookupValue1));
    
project->Save(dataDir + u"AddExtendedAttributesToRAWithLookUp_out.mpp", Aspose::Tasks::Saving::SaveFileFormat::MPP);