AF SDK Reference

Loading Partial Elements

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Loading Partial Elements

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Last UpdatedJan 12, 2026
6 minute read

This topic contains the following sections:

Partial Load Elements by IDs
Partial Load Elements from Search
See Also

Typically, a top-level object in the AF SDK is either fully-loaded, or just has the header information for it loaded. Often, however, there is a need to just access a few specific attributes from a collection of elements. These examples use the LoadAttributes methods to load a specific list of attributes into the client. By only loading a partial set of attributes, the amount of information required to be transferred from the server to the client is reduced, resulting in faster performance and a lower memory footprint.

Partial Load Elements by IDs

This example demonstrates using the AFSearchFindObjectIds method to obtain a list of element unique identifiers and then partially load some of the element's attributes.

 1// Get the Database
 2PISystems myPISystems = new PISystems();
 3PISystem myPISystem = myPISystems.DefaultPISystem;
 4if (myPISystem == null)
 5    throw new InvalidOperationException("Default PISystem was not found.");
 6AFDatabase myDB = myPISystem.Databases[dbName];
 7if (myDB == null)
 8    throw new InvalidOperationException("Database was not found.");
 9
10// Use attribute value query to find a list of tanks that are 
11// In Service (tanks which are out-of-service have their 
12// Status attribute set to "OS").
13int totalCount = 0;
14using (var search = new AFElementSearch(myDB, "FindTanks", @"Template:'TankAdvanced' |Status:<>'OS'"))
15{
16    search.CacheTimeout = TimeSpan.FromMinutes(10);
17
18    // Because we are only going to use a few of the attributes for each
19    // of the elements found, we can reduce the load time and memory space
20    // by just loading the attributes we need.  Note that if we inadvertently
21    // use attributes other than these, we will incur a load penalty.
22    AFElementTemplate tankTemplate = myDB.ElementTemplates["Tank"];
23    AFNamedCollectionList<AFAttributeTemplate> myAttributes =
24        new AFNamedCollectionList<AFAttributeTemplate>();
25    myAttributes.Add(tankTemplate.AttributeTemplates["Volume"]);
26    myAttributes.Add(tankTemplate.AttributeTemplates["Level"]);
27    myAttributes.Add(tankTemplate.AttributeTemplates["Level|HighLimit"]);
28    myAttributes.Add(tankTemplate.AttributeTemplates["Level|LowLimit"]);
29
30    // Get today's date and UOMs to be used for converting values.
31    AFTime today = new AFTime("T", CultureInfo.CurrentCulture);
32    UOM bbl = myDB.PISystem.UOMDatabase.UOMs["bbl"];
33    UOM meter = myDB.PISystem.UOMDatabase.UOMs["m"];
34
35    const int pageSize = 1000;
36    int startIndex = 0;
37    IList<Guid> myElementIds = new List<Guid>(pageSize);
38    do
39    {
40        // Find the element IDs and load the attributes we will be using.
41        var results = search.FindObjectIds(startIndex, pageSize: pageSize);
42        myElementIds.Clear();
43        int c = 0;
44        foreach (Guid id in results)
45        {
46            totalCount++;
47            myElementIds.Add(id);
48            c++;
49            if (c >= pageSize)
50                break;
51        }
52
53        if (myElementIds.Count == 0) break;
54        AFNamedCollectionList<AFElement> elements =
55            AFElement.LoadAttributes(myPISystem, myElementIds, myAttributes);
56
57        // Once the elements are loaded, we can process them.
58        foreach (AFElement element in elements)
59        {
60            try
61            {
62                AFAttributeList attributes = new AFAttributeList();
63                attributes.Add(element.Attributes["Volume"]);
64                attributes.Add(element.Attributes["Level"]);
65                attributes.Add(element.Attributes["Level|HighLimit"]);
66                attributes.Add(element.Attributes["Level|LowLimit"]);
67                AFValues values = attributes.GetValue(today);
68
69                if (values[0].IsGood && values[1].IsGood &&
70                    values[2].IsGood && values[3].IsGood)
71                {
72                    double volume = (double)values[0].Convert(bbl).Value;
73                    double level = (double)values[1].Convert(meter).Value;
74                    double high = (double)values[2].Convert(meter).Value;
75                    double low = (double)values[3].Convert(meter).Value;
76
77                    Console.WriteLine("Tank Inventory for '{0}' is {1} bbl.  %Full={2}",
78                        element.Name, volume, 100 * (high - low) / level);
79                }
80                else
81                {
82                    Console.WriteLine("Bad data in Tank '{0}'", element.Name);
83                }
84            }
85            catch (FormatException)
86            {
87                Console.WriteLine("Error in Tank '{0}'", element.Name);
88            }
89        }
90
91        startIndex += myElementIds.Count; // Advance to next page.
92    } while (myElementIds.Count > 0 && myElementIds.Count >= pageSize);
93}
94
95Console.WriteLine("Processed {0} Elements.", totalCount);

Partial Load Elements from Search

This example demonstrates partially loading elements using the AFElementSearchFindElements method to find the element headers and then partially load some of the element's attributes.

 1// Get the Database
 2PISystems myPISystems = new PISystems();
 3PISystem myPISystem = myPISystems.DefaultPISystem;
 4if (myPISystem == null)
 5    throw new InvalidOperationException("Default PISystem was not found.");
 6AFDatabase myDB = myPISystem.Databases[dbName];
 7if (myDB == null)
 8    throw new InvalidOperationException("Database was not found.");
 9
10// Use attribute value query to find a list of tanks that are 
11// In Service (tanks which are out-of-service have their 
12// Status attribute set to "OS").
13int totalCount = 0;
14using (var search = new AFElementSearch(myDB, "FindTanks", @"Template:'TankAdvanced' |Status:<>'OS'"))
15{
16    search.CacheTimeout = TimeSpan.FromMinutes(10);
17
18    // Because we are only going to use a few of the attributes for each
19    // of the elements found, we can reduce the load time and memory space
20    // by just loading the attributes we need.  Note that if we inadvertently
21    // use attributes other than these, we will incur a load penalty.
22    AFElementTemplate tankTemplate = myDB.ElementTemplates["Tank"];
23    AFNamedCollectionList<AFAttributeTemplate> myAttributes =
24        new AFNamedCollectionList<AFAttributeTemplate>();
25    myAttributes.Add(tankTemplate.AttributeTemplates["Volume"]);
26    myAttributes.Add(tankTemplate.AttributeTemplates["Level"]);
27    myAttributes.Add(tankTemplate.AttributeTemplates["Level|HighLimit"]);
28    myAttributes.Add(tankTemplate.AttributeTemplates["Level|LowLimit"]);
29
30    // Get today's date and UOMs to be used for converting values.
31    AFTime today = new AFTime("T", CultureInfo.CurrentCulture);
32    UOM bbl = myDB.PISystem.UOMDatabase.UOMs["bbl"];
33    UOM meter = myDB.PISystem.UOMDatabase.UOMs["m"];
34
35    const int pageSize = 1000;
36    int startIndex = 0;
37    IList<AFElement> myElements = new List<AFElement>(pageSize);
38    do
39    {
40        // Find the elements and load the attributes we will be using.
41        var results = search.FindObjects(startIndex, fullLoad: false, pageSize: pageSize);
42        myElements.Clear();
43        int c = 0;
44        foreach (AFElement item in results)
45        {
46            totalCount++;
47            myElements.Add(item);
48            c++;
49            if (c >= pageSize)
50                break;
51        }
52
53        if (myElements.Count == 0) break;
54        AFElement.LoadAttributes(myElements, myAttributes);
55
56        // Once the elements are loaded, we can process them.
57        foreach (AFElement element in myElements)
58        {
59            try
60            {
61                AFAttributeList attributes = new AFAttributeList();
62                attributes.Add(element.Attributes["Volume"]);
63                attributes.Add(element.Attributes["Level"]);
64                attributes.Add(element.Attributes["Level|HighLimit"]);
65                attributes.Add(element.Attributes["Level|LowLimit"]);
66                AFValues values = attributes.GetValue(today);
67
68                if (values[0].IsGood && values[1].IsGood &&
69                    values[2].IsGood && values[3].IsGood)
70                {
71                    double volume = (double)values[0].Convert(bbl).Value;
72                    double level = (double)values[1].Convert(meter).Value;
73                    double high = (double)values[2].Convert(meter).Value;
74                    double low = (double)values[3].Convert(meter).Value;
75
76                    Console.WriteLine("Tank Inventory for '{0}' is {1} bbl.  %Full={2}",
77                        element.Name, volume, 100 * (high - low) / level);
78                }
79                else
80                {
81                    Console.WriteLine("Bad data in Tank '{0}'", element.Name);
82                }
83            }
84            catch (FormatException)
85            {
86                Console.WriteLine("Error in Tank '{0}'", element.Name);
87            }
88        }
89
90        startIndex += myElements.Count; // Advance to next page.
91    } while (myElements.Count > 0 && myElements.Count >= pageSize);
92}
93
94Console.WriteLine("Processed {0} Elements.", totalCount);

AF SDK Reference