ExpressionEvaluator Class (PIA)
Use this object to evaluate one or more expressions against a specified context. In addition, use this object to parse and evaluate user-defined expressions written as Extensible Markup Language (XML) fragments.
Methods
| Method | Description |
|---|---|
| Connect | Establishes communication between the ExpressionEvaluator object and an expression store. |
| CreateEvalContext | Creates a new ExprEvalContext object in the context cache. |
| Eval | Evaluates an expression. |
| EvalInContext | Evaluates an expression in a context previously loaded into the context cache. |
| EvalXML | Evaluates the specified XML text as an expression. |
| FlushAll | Removes all expressions from the expression cache. |
| FlushExpr | Removes the specified expression from the expression cache. |
| LoadAll | Reads all expressions from the expression store and loads them into the expression cache. |
| LoadExpr | Reads the specified expression from the expression store and loads it into the expression cache. |
| ParseXML | Parses the specified XML text to determine whether it represents a valid expression. |
Properties
| Property | Type | Description |
|---|---|---|
| ExprCount | Integer | Retrieves the number of expressions loaded into the expression cache.
This property is read-only. |
Remarks
Expressions are stored in a database referred to as the Expression Store and accessed through an ExpressionStore object. When it is created, the ExpressionEvaluator object initializes an expression cache and a context cache. Expressions must be compiled and loaded into the expression cache before being evaluated. To improve evaluation performance, use the LoadExpr or LoadAll method to preload expressions into the expression cache.
An expression is evaluated against data contained in a set of profiles. The profiles may be ProfileObject objects, or Dictionary objects. The set of profiles is referred to as an evaluation context. If an evaluation context will be used across multiple expressions, create a stored context in the context cache using the CreateEvalContext method to increase efficiency.
The Connect method must be called before loading or evaluating expressions.
Requirements
Namespace: Microsoft.CommerceServer.Interop.Targeting
Platforms: Windows 2000, Windows Server 2003
Assembly: exprarchlib (in exprarchlib.dll)
See Also
Copyright © 2005 Microsoft Corporation.
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