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 )
Parameters
- entry
- Type: System.Web.UI.BoundPropertyEntry
The object that represents information about the property bound to by the expression.
- parsedData
- Type: System.Object
The object containing parsed data as returned by ParseExpression.
- context
- Type: System.Web.Compilation.ExpressionBuilderContext
Contextual information for the evaluation of the expression.
Return Value
Type: System.CodeDom.CodeExpressionA CodeExpression that is used for property assignment.
Classes that inherit from the ExpressionBuilder class must implement the GetCodeExpression abstract method.
Notes to InheritorsIf 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 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
