NJection

NJection Announced

Sagi Fogel — 2009-11-30T07:25:00

The NJection project provides a way to inject .NET code at runtime using configuration files.
NJection uses new capabilities of the System.Linq.Expressions namespace which comes with visual studio 2010 and .NET 4.0 Framework.

Here we defined a method call to WriteLine of the static class Console.

C# Example

LambdaExpression ex = ExpressionBuilder.Traverse<LambdaExpression>(@"C:\Example.config");
Action<string> action = ex.Compile() as Action<string>;
action("Hello World!");

Configuration Example

<?xml version="1.0" encoding="utf-8"?>

<expressiontype="Lambda" typeof="System.Action`1[System.String]">

<expressiontype="Call" typeof="System.Console" kind="Static" methodName="WriteLine">

<expressionref="valueParameter"/>

</arguments>

</expression>

<expressiontype="Parameter" typeof="System.String"name="valueParameter"/>

</arguments>

</expression>

</configuration>

Expressions Configuration Changes

Sagi Fogel — 2010-01-24T14:04:46.353

Lambda Expression
Arguments for the the Lambda expression are no longer defined in the definitions
element and using the ref attribute is no longer needed. Instead, defining an argumnet for the the Lambda expression is done in the arguments element.
func & action elements which were indicated the type of the Lambda are obsolete.
Instead defining the type of the Lambda is done with the typeof attribute in the Lambda expression e.g.

<expression type="Lambda" typeof="System.Action`1[System.String]">
Lambda's return elemnt which indicated the returned expression is obsolete.
Instead defining the return expression is done within a Block expression.
Lambda's variables element has been changed to arguments.
Call Expression
The static and methodInfo elements of Call are obsolete.
Instead defining a call for a static type method is done by defining the kind attribute to be Static e.g.

<expression type="Call" kind="Static" typeof="System.Console" methodName="Write">
Goto Expression
The break & continue elements which indicated the type of goto are obsolete.
Instead defining the type of goto is done with the kind attribute in the Goto expression element e.g.

<expression type="Goto" kind="Break">
Goto expression now supports 4 kinds: Goto, Break, Continue, Return.
Block Expression
Block's variables element has been changed to arguments.

New Expressions Support

Sagi Fogel — 2010-05-07T07:43:27.377

New Expressions Support.
Try - Creates a Try expression representing a try block with any number of catch statements.
Catch - Represents a catch statement in a try block.
Switch - Represents a switch statement.
SwitchCase -Represents a control expression that handles multiple selections by passing control to SwitchCase.
New - Represents a constructor call.
NewArrayBounds - Rpresents creating a new array that has a specified rank.
NewArrayInit - Represents creating a one-dimensional array and initializing it from a list of elements.
ArrayIndex - Represents creating a one-dimensional array and initializing it from a list of elements.
Index - Represents an access to an array, for assigning to, or reading from, an array element.
ListInit - Represents a constructor call that has a collection initializer.
ListBinding - Initializes a list in a specific type where the list is exposed as a public property or field.
MemberInit - Represents calling a constructor and initializing one or more members of the new object.
MemberBinding - Represents a recursive initialization of members of a field or property.
MemberAccess - Represents accessing a property or field.
TypeEqual - Represents a a run time identity check for an expression with a given type.
TypeIs - Represents a compatible check for an expression with a given type.
Invoke - Represents an expression that applies lambda expression to a list of arguments.
All Expressions
The body element is obsolete, instead use the expression element.
Block Expression
The result element is obsolete, instead the result value & type would be the last expression of the Block expression.
Conditional Expression
The expressions element is obsolete. test, ifTrue, IfFalse elements are now direct children of the conditional expression.
Goto Expression
LabeTarget element is obsolete, instead a label element containing the label expression is required.
Binary Expression
Binary's expressions element is obsolete . left & right elements are now direct children of the Binary expression.