Catch<TException> Class

.NET Framework (current version)

Contains the actions to be executed after an exception is raised in the corresponding Try block of a T:System.Activities.Statements.TryCatchFinally activity.

Namespace:   System.Activities.Statements
Assembly:  System.Activities (in System.Activities.dll)


public sealed class Catch<TException> : Catch
where TException : Exception

Type Parameters


The type of exception that the Catch<TException> block is handling.


Creates a new instance of the Catch<TException> class.


The handler for the exception being caught.


The type of exception that the Catch block is handling.(Overrides Catch.ExceptionType.)


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


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


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


Returns a string that represents the current object.(Inherited from Object.)

Once placed in the designer, Catch activities cannot be reordered in the designer. To reorder the collection of Catch activities, either delete and re-add them in the correct order, or use the xaml (code) view for the workflow.

The following code sample demonstrates creating a Catch<TException> activity. This example is from the Fault Handling in a Flowchart Activity Using TryCatch sample.

FlowStep mwkStep = new FlowStep
    Action = new TryCatch
        DisplayName = "Try/Catch for Divide By Zero Exception",
        Try = new Assign
            DisplayName = "discount = 15 + (1 - 1/numberOfKids)*10",
            To = new OutArgument<double>(discount),
            Value = new InArgument<double>((ctx) => (15 + (1 - 1 / numberOfKids.Get(ctx)) * 10))
        Catches = 
             new Catch<System.DivideByZeroException>
                 Action = new ActivityAction<System.DivideByZeroException>
                     Argument = ex,
                     DisplayName = "ActivityAction - DivideByZeroException",
                     Handler =
                         new Sequence
                             DisplayName = "Divide by Zero Exception Workflow",
                             Activities =
                                new WriteLine() 
                                    DisplayName = "WriteLine: DivideByZeroException",
                                    Text = "DivideByZeroException: Promo code is MWK - but number of kids = 0" 
                                new Assign<double>
                                    DisplayName = "Exception - discount = 0", 
                                    To = discount,
                                    Value = new InArgument<double>(0)
    Next = flowDecision

.NET Framework
Available since 4.0

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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