AF SDK Reference

Loading Partial Elements

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Loading Partial Elements

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Last UpdatedNov 18, 2025
10 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);

 1' Get the Database
 2Dim myPISystems As New PISystems()
 3Dim myPISystem As PISystem = myPISystems.DefaultPISystem
 4If myPISystem Is Nothing Then
 5    Throw New InvalidOperationException("Default PISystem was not found.")
 6End If
 7Dim myDB As AFDatabase = myPISystem.Databases(dbName)
 8If myDB Is Nothing Then
 9    Throw New InvalidOperationException("Database was not found.")
10End If
11
12' Use attribute value query to find a list of tanks that are 
13' In Service (tanks which are out-of-service have their 
14' Status attribute set to "OS").
15Dim totalCount As Integer = 0
16Using search As New AFElementSearch(myDB, "FindTanks", "Template:'TankAdvanced' |Status:<>'OS'")
17
18    search.CacheTimeout = TimeSpan.FromMinutes(10)
19
20    ' Because we are only going to use a few of the attributes for each
21    ' of the elements found, we can reduce the load time and memory space
22    ' by just loading the attributes we need.  Note that if we inadvertently
23    ' use attributes other than these, we will incur a load penalty.
24    Dim tankTemplate As AFElementTemplate = myDB.ElementTemplates("Tank")
25    Dim myAttributes As New AFNamedCollectionList(Of AFAttributeTemplate)()
26    myAttributes.Add(tankTemplate.AttributeTemplates("Volume"))
27    myAttributes.Add(tankTemplate.AttributeTemplates("Level"))
28    myAttributes.Add(tankTemplate.AttributeTemplates("Level|HighLimit"))
29    myAttributes.Add(tankTemplate.AttributeTemplates("Level|LowLimit"))
30
31    ' Get today's date and UOMs to be used for converting values.
32    Dim today As New AFTime("T", CultureInfo.CurrentCulture)
33    Dim bbl As UOM = myDB.PISystem.UOMDatabase.UOMs("bbl")
34    Dim meter As UOM = myDB.PISystem.UOMDatabase.UOMs("m")
35
36    Const pageSize As Integer = 1000
37    Dim startIndex As Integer = 0
38    Dim myElementIds As IList(Of Guid) = New List(Of Guid)(pageSize)
39    Do
40        ' Find the elements and load the attributes we will be using.
41        Dim results As IEnumerable(Of Guid) = search.FindObjectIds(startIndex, pageSize:=pageSize)
42        myElementIds.Clear()
43        Dim c As Integer = 0
44        For Each id As Guid In results
45            totalCount += 1
46            myElementIds.Add(id)
47            c += 1
48            If c >= pageSize Then
49                Exit For
50            End If
51        Next
52
53        If myElementIds.Count = 0 Then
54            Exit Do
55        End If
56        Dim elements As AFNamedCollectionList(Of AFElement) =
57            AFElement.LoadAttributes(myPISystem, myElementIds, myAttributes)
58
59        ' Once the elements are loaded, we can process them.
60        For Each element As AFElement In elements
61            Try
62                Dim attributes As 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                Dim values As AFValues = attributes.GetValue(today)
68
69                If values(0).IsGood AndAlso values(1).IsGood AndAlso values(2).IsGood AndAlso values(3).IsGood Then
70                    Dim volume As Double = CDbl(values(0).Convert(bbl).Value)
71                    Dim level As Double = CDbl(values(1).Convert(meter).Value)
72                    Dim high As Double = CDbl(values(2).Convert(meter).Value)
73                    Dim low As Double = CDbl(values(3).Convert(meter).Value)
74
75                    Console.WriteLine("Tank Inventory for '{0}' is {1} bbl.  %Full={2}", element.Name, volume, 100 * (high - low) / level)
76                Else
77                    Console.WriteLine("Bad data in Tank '{0}'", element.Name)
78                End If
79            Catch generatedExceptionName As FormatException
80                Console.WriteLine("Error in Tank '{0}'", element.Name)
81            End Try
82        Next
83
84        ' Advance to next page.
85        startIndex += myElementIds.Count
86    Loop While myElementIds.Count > 0 AndAlso myElementIds.Count >= pageSize
87End Using
88
89Console.WriteLine("Processed {0} Elements.", totalCount)

No code example is currently available or this language may not be supported.

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);

 1' Get the Database
 2Dim myPISystems As New PISystems()
 3Dim myPISystem As PISystem = myPISystems.DefaultPISystem
 4If myPISystem Is Nothing Then
 5    Throw New InvalidOperationException("Default PISystem was not found.")
 6End If
 7Dim myDB As AFDatabase = myPISystem.Databases(dbName)
 8If myDB Is Nothing Then
 9    Throw New InvalidOperationException("Database was not found.")
10End If
11
12' Use attribute value query to find a list of tanks that are 
13' In Service (tanks which are out-of-service have their 
14' Status attribute set to "OS").
15Dim totalCount As Integer = 0
16Using search As New AFElementSearch(myDB, "FindTanks", "Template:'TankAdvanced' |Status:<>'OS'")
17
18    search.CacheTimeout = TimeSpan.FromMinutes(10)
19
20    ' Because we are only going to use a few of the attributes for each
21    ' of the elements found, we can reduce the load time and memory space
22    ' by just loading the attributes we need.  Note that if we inadvertently
23    ' use attributes other than these, we will incur a load penalty.
24    Dim tankTemplate As AFElementTemplate = myDB.ElementTemplates("Tank")
25    Dim myAttributes As New AFNamedCollectionList(Of AFAttributeTemplate)()
26    myAttributes.Add(tankTemplate.AttributeTemplates("Volume"))
27    myAttributes.Add(tankTemplate.AttributeTemplates("Level"))
28    myAttributes.Add(tankTemplate.AttributeTemplates("Level|HighLimit"))
29    myAttributes.Add(tankTemplate.AttributeTemplates("Level|LowLimit"))
30
31    ' Get today's date and UOMs to be used for converting values.
32    Dim today As New AFTime("T", CultureInfo.CurrentCulture)
33    Dim bbl As UOM = myDB.PISystem.UOMDatabase.UOMs("bbl")
34    Dim meter As UOM = myDB.PISystem.UOMDatabase.UOMs("m")
35
36    Const pageSize As Integer = 1000
37    Dim startIndex As Integer = 0
38    Dim myElements As IList(Of AFElement) = New List(Of AFElement)(pageSize)
39    Do
40        ' Find the elements and load the attributes we will be using.
41        Dim results As IEnumerable(Of AFElement) = search.FindObjects(startIndex, fullLoad:=False, pageSize:=pageSize)
42        myElements.Clear()
43        Dim c As Integer = 0
44        For Each item As AFElement In results
45            totalCount += 1
46            myElements.Add(item)
47            c += 1
48            If c >= pageSize Then
49                Exit For
50            End If
51        Next
52
53        If myElements.Count = 0 Then
54            Exit Do
55        End If
56        AFElement.LoadAttributes(myElements, myAttributes)
57
58        ' Once the elements are loaded, we can process them.
59        For Each element As AFElement In myElements
60            Try
61                Dim attributes As 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                Dim values As AFValues = attributes.GetValue(today)
67
68                If values(0).IsGood AndAlso values(1).IsGood AndAlso values(2).IsGood AndAlso values(3).IsGood Then
69                    Dim volume As Double = CDbl(values(0).Convert(bbl).Value)
70                    Dim level As Double = CDbl(values(1).Convert(meter).Value)
71                    Dim high As Double = CDbl(values(2).Convert(meter).Value)
72                    Dim low As Double = CDbl(values(3).Convert(meter).Value)
73
74                    Console.WriteLine("Tank Inventory for '{0}' is {1} bbl.  %Full={2}", element.Name, volume, 100 * (high - low) / level)
75                Else
76                    Console.WriteLine("Bad data in Tank '{0}'", element.Name)
77                End If
78            Catch generatedExceptionName As FormatException
79                Console.WriteLine("Error in Tank '{0}'", element.Name)
80            End Try
81        Next
82
83        ' Advance to next page.
84        startIndex += myElements.Count
85    Loop While myElements.Count > 0 AndAlso myElements.Count >= pageSize
86End Using
87
88Console.WriteLine("Processed {0} Elements.", totalCount)

No code example is currently available or this language may not be supported.

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