TryExpression Class

 

Represents a try/catch/finally/fault block.

Namespace:   System.Linq.Expressions
Assembly:  System.Core (in System.Core.dll)

System.Object
  System.Linq.Expressions.Expression
    System.Linq.Expressions.TryExpression

public sealed class TryExpression : Expression

NameDescription
System_CAPS_pubpropertyBody

Gets the Expression representing the body of the try block.

System_CAPS_pubpropertyCanReduce

Indicates that the node can be reduced to a simpler node. If this returns true, Reduce() can be called to produce the reduced form.(Inherited from Expression.)

System_CAPS_pubpropertyFault

Gets the Expression representing the fault block.

System_CAPS_pubpropertyFinally

Gets the Expression representing the finally block.

System_CAPS_pubpropertyHandlers

Gets the collection of CatchBlock expressions associated with the try block.

System_CAPS_pubpropertyNodeType

Returns the node type of this Expression.(Overrides Expression.NodeType.)

System_CAPS_pubpropertyType

Gets the static type of the expression that this Expression represents.(Overrides Expression.Type.)

NameDescription
System_CAPS_protmethodAccept(ExpressionVisitor)

Dispatches to the specific visit method for this node type. For example, MethodCallExpression calls the VisitMethodCall.(Inherited from Expression.)

System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodReduce()

Reduces this node to a simpler expression. If CanReduce returns true, this should return a valid expression. This method can return another node which itself must be reduced.(Inherited from Expression.)

System_CAPS_pubmethodReduceAndCheck()

Reduces this node to a simpler expression. If CanReduce returns true, this should return a valid expression. This method can return another node which itself must be reduced.(Inherited from Expression.)

System_CAPS_pubmethodReduceExtensions()

Reduces the expression to a known node type (that is not an Extension node) or just returns the expression if it is already a known type.(Inherited from Expression.)

System_CAPS_pubmethodToString()

Returns a textual representation of the Expression.(Inherited from Expression.)

System_CAPS_pubmethodUpdate(Expression, IEnumerable<CatchBlock>, Expression, Expression)

Creates a new expression that is like this one, but using the supplied children. If all of the children are the same, it will return this expression.

System_CAPS_protmethodVisitChildren(ExpressionVisitor)

Reduces the node and then calls the visitor delegate on the reduced expression. The method throws an exception if the node is not reducible.(Inherited from Expression.)

The body block is protected by the try block.

The handlers consist of a set of CatchBlock expressions that can be either catch statements or filters.

The fault block runs if an exception is thrown.

The finally block runs regardless of how control exits the body.

Only one of fault or finally blocks can be supplied.

The return type of the try block must match the return type of any associated catch statements.

The following example demonstrates how to create a TryExpression object that contains a catch statement by using the TryCatch method.

// Add the following directive to the file:
// using System.Linq.Expressions;  

// A TryExpression object that has a Catch statement.
// The return types of the Try block and all Catch blocks must be the same.
TryExpression tryCatchExpr =
    Expression.TryCatch(
        Expression.Block(
            Expression.Throw(Expression.Constant(new DivideByZeroException())),
            Expression.Constant("Try block")
        ),
        Expression.Catch(
            typeof(DivideByZeroException),
            Expression.Constant("Catch block")
        )
    );

// The following statement first creates an expression tree,
// then compiles it, and then runs it.
// If the exception is caught, 
// the result of the TryExpression is the last statement 
// of the corresponding Catch statement.
Console.WriteLine(Expression.Lambda<Func<string>>(tryCatchExpr).Compile()());

// This code example produces the following output:
//
// Catch block

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 4.0
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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