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   How to: Access Data in SQL Query Results
   How to: Bind an XPCollection to a LookUp
   How to: Bind an XPCollection to Standard Controls
   How to: Bind an XPCollection to the DataGrid
   How to: Bind an XPCollection to the Grid
   How to: Build Complex Criteria
   How to: Build Simple Criteria
   How to: Change Inheritance Mapping
   How to: Connect to a SQL Server
   How to: Connect to SQL Azure
   How to: Connect XPO to a Database Other than MS SQL or MS Access
   How to: Control Automatic Saving of Objects when Editing in a Grid
   How to: Create an Aggregated Object
   How to: Delay Property Loading
   How to: Filter By DateTime Values
   How to: Filter Persistent Objects by Type
   How to: Handle Persistent Object Initialization
   How to: Implement a Custom Criteria Language Function Operator
   How to: Implement a Full-Text Search
   How to: Implement Custom Functions and Criteria in LINQ to XPO
   How to: Implement Many-to-Many Relationships
   How to: Implement One-to-One Relationships
   How to: Link Classes Located in Different Assemblies
   How to: Make a Class or Property Non-Persistent
   How to: Make XPCollection Create Objects of Specific Type when They are Created via Bound Controls
   How to: Map to Custom Tables (Views) and Columns
   How to: Obtain a Collection of Persistent Objects by a Set of Their IDs
   How to: Obtain a Collection of Persistent Objects for Processing
   How to: Persist a BLOB Field
   How to: Prevent Changes in a Persistent Object from being Automatically Committed
   How to: Restore Deleted Objects
   How to: Use Pageable Collections
   How to: Use Read-Only Persistent Properties
   How to: Use the ContainsOperator for Objects in a Many-to-Many Relationship
   How to: Validate an Object
   How to: Work with Structures
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How to: Use Pageable Collections

This example provides a memory usage comparison between the XPCollection and XPCursor instances.

Creating and persisting the objects in the database.

Then we iterate through the contents of the XPCollection and XPCursor and modify the values of the retrieved objects. We assess the amount of memory allocated every time one hundred objects have been modified.

The table below shows the result:

Processing objects with XPCursor

Processing objects with XPCollection

Object 100, memory allocated 382752

Object 200, memory allocated 389152

Object 300, memory allocated 395552

Object 400, memory allocated 386336

Object 500, memory allocated 392736

Object 600, memory allocated 386336

Object 700, memory allocated 392736

Object 800, memory allocated 386336

Object 900, memory allocated 392736

Object 1000, memory allocated 386036

Object 100, memory allocated 2568928

Object 200, memory allocated 2568504

Object 300, memory allocated 2568504

Object 400, memory allocated 2568504

Object 500, memory allocated 2568504

Object 600, memory allocated 2568492

Object 700, memory allocated 2568492

Object 800, memory allocated 2568492

Object 900, memory allocated 2568492

Object 1000, memory allocated 2568492

From the output you can see that the XPCursor has significantly improved the way in which memory is allocated for the collection's contents.

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