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ExpressionBuilder.GetCodeExpression Method

When overridden in a derived class, returns code that is used during page execution to obtain the evaluated expression.

Namespace: System.Web.Compilation
Assembly: System.Web (in system.web.dll)

public abstract CodeExpression GetCodeExpression (
	BoundPropertyEntry entry,
	Object parsedData,
	ExpressionBuilderContext context
)
public abstract CodeExpression GetCodeExpression (
	BoundPropertyEntry entry, 
	Object parsedData, 
	ExpressionBuilderContext context
)
public abstract function GetCodeExpression (
	entry : BoundPropertyEntry, 
	parsedData : Object, 
	context : ExpressionBuilderContext
) : CodeExpression
Not applicable.

Parameters

entry

The object that represents information about the property bound to by the expression.

parsedData

The object containing parsed data as returned by ParseExpression.

context

Contextual information for the evaluation of the expression.

Return Value

A CodeExpression that is used for property assignment.

Classes that inherit from the ExpressionBuilder class must implement the GetCodeExpression abstract method.

Notes to Inheritors: If you implement a custom expression builder, you must perform the proper type casting for the control property and return the cast operation in the CodeExpression object.

The following code example demonstrates how to return a CodeExpression object by overriding the GetCodeExpression method.

public override CodeExpression GetCodeExpression(BoundPropertyEntry entry, 
object parsedData, ExpressionBuilderContext context)
{
    Type type1 = entry.DeclaringType;
    PropertyDescriptor descriptor1 = TypeDescriptor.GetProperties(type1)[entry.PropertyInfo.Name];
    CodeExpression[] expressionArray1 = new CodeExpression[3];
    expressionArray1[0] = new CodePrimitiveExpression(entry.Expression.Trim());
    expressionArray1[1] = new CodeTypeOfExpression(type1);
    expressionArray1[2] = new CodePrimitiveExpression(entry.Name);
    return new CodeCastExpression(descriptor1.PropertyType, new CodeMethodInvokeExpression(new 
   CodeTypeReferenceExpression(base.GetType()), "GetEvalData", expressionArray1));
}

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

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