System.Linq.Expressions Namespace

Contains classes, interfaces and enumerations that enable language-level code expressions to be represented as objects in the form of expression trees.

Classes

BinaryExpression	Represents an expression that has a binary operator.
BlockExpression	Represents a block that contains a sequence of expressions where variables can be defined.
CatchBlock	Represents a catch statement in a try block.
ConditionalExpression	Represents an expression that has a conditional operator.
ConstantExpression	Represents an expression that has a constant value.
DebugInfoExpression	Emits or clears a sequence point for debug information. This allows the debugger to highlight the correct source code when debugging.
DefaultExpression	Represents the default value of a type or an empty expression.
DynamicExpression	Represents a dynamic operation.
DynamicExpressionVisitor	Represents a visitor or rewriter for dynamic expression trees.
ElementInit	Represents an initializer for a single element of an IEnumerable collection.
Expression	Provides the base class from which the classes that represent expression tree nodes are derived. It also contains static (Shared in Visual Basic) factory methods to create the various node types. This is an abstract class.
Expression<TDelegate>	Represents a strongly typed lambda expression as a data structure in the form of an expression tree. This class cannot be inherited.
ExpressionVisitor	Represents a visitor or rewriter for expression trees.
GotoExpression	Represents an unconditional jump. This includes return statements, break and continue statements, and other jumps.
IndexExpression	Represents indexing a property or array.
InvocationExpression	Represents an expression that applies a delegate or lambda expression to a list of argument expressions.
LabelExpression	Represents a label, which can be put in any Expression context. If it is jumped to, it will get the value provided by the corresponding GotoExpression. Otherwise, it receives the value in DefaultValue. If the Type equals System.Void, no value should be provided.
LabelTarget	Used to represent the target of a GotoExpression.
LambdaExpression	Describes a lambda expression. This captures a block of code that is similar to a .NET method body.
ListInitExpression	Represents a constructor call that has a collection initializer.
LoopExpression	Represents an infinite loop. It can be exited with "break".
MemberAssignment	Represents assignment operation for a field or property of an object.
MemberBinding	Provides the base class from which the classes that represent bindings that are used to initialize members of a newly created object derive.
MemberExpression	Represents accessing a field or property.
MemberInitExpression	Represents calling a constructor and initializing one or more members of the new object.
MemberListBinding	Represents initializing the elements of a collection member of a newly created object.
MemberMemberBinding	Represents initializing members of a member of a newly created object.
MethodCallExpression	Represents a call to either static or an instance method.
NewArrayExpression	Represents creating a new array and possibly initializing the elements of the new array.
NewExpression	Represents a constructor call.
ParameterExpression	Represents a named parameter expression.
RuntimeVariablesExpression	An expression that provides runtime read/write permission for variables.
SwitchCase	Represents one case of a SwitchExpression.
SwitchExpression	Represents a control expression that handles multiple selections by passing control to SwitchCase.
SymbolDocumentInfo	Stores information necessary to emit debugging symbol information for a source file, in particular the file name and unique language identifier.
TryExpression	Represents a try/catch/finally/fault block.
TypeBinaryExpression	Represents an operation between an expression and a type.
UnaryExpression	Represents an expression that has a unary operator.

Interfaces

IArgumentProvider	Provides an internal interface for accessing the arguments of multiple tree nodes (DynamicExpression, ElementInit, MethodCallExpression, InvocationExpression, NewExpression, and IndexExpression). This API is for internal use only.
IDynamicExpression	Provides an internal interface for accessing the arguments of DynamicExpression tree nodes as well as CallSite and Rewriting functionality. You should not use this API. It is only public due to DLL refactoring and exists only for internal performance optimizations.

Enums

ExpressionType	Describes the node types for the nodes of an expression tree.
GotoExpressionKind	Specifies what kind of jump this GotoExpression represents.
MemberBindingType	Describes the binding types that are used in MemberInitExpression objects.

Remarks

The abstract class Expression provides the root of a class hierarchy used to model expression trees.

The classes in this namespace that derive from Expression, for example MemberExpression and ParameterExpression, are used to represent nodes in an expression tree. The Expression class contains static (Shared in Visual Basic) factory methods to create expression tree nodes of the various types.

The enumeration type ExpressionType specifies the unique node types.

See also

• Expression Trees (C#)
• Expression Trees (Visual Basic)