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If Class

.NET Framework 4.6 and 4.5

Models an If-Then-Else condition.

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

public sealed class If : NativeActivity

The If type exposes the following members.

  NameDescription
Public methodIf()Creates a new instance of the If class.
Public methodIf(Activity<Boolean>)Creates a new instance of the If class using the specified condition.
Public methodIf(InArgument<Boolean>)Creates a new instance of the If class using the specified condition.
Public methodIf(Expression<Func<ActivityContext, Boolean>>)Creates a new instance of the If class using the specified condition.
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  NameDescription
Protected propertyCacheIdGets the identifier of the cache that is unique within the scope of the workflow definition. (Inherited from Activity.)
Public propertyConditionThe condition that determines which child activity to execute. The Then activity executes if the condition resolves to true. The Else activity executes if the condition resolves to false.
Public propertyDisplayNameGets or sets an optional friendly name that is used for debugging, validation, exception handling, and tracking. (Inherited from Activity.)
Public propertyElseThe activity to be executed if the activity’s Condition resolves to false.
Public propertyIdGets an identifier that is unique in the scope of the workflow definition. (Inherited from Activity.)
Protected propertyImplementationVersionGets or sets the implementation version of the activity. (Inherited from NativeActivity.)
Public propertyThenThe activity to be executed if the activity’s Condition resolves to true.
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  NameDescription
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodShouldSerializeDisplayNameIndicates whether the DisplayName property should be serialized. (Inherited from Activity.)
Public methodToStringReturns a String that contains the Id and DisplayName of the Activity. (Inherited from Activity.)
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The following code sample demonstrates creating an If activity. This example is from the Sending and Handling Faults sample.

new If 
{
    // check if the order is asking for Widgets
    Condition = new InArgument<bool>( (e) => po.Get(e).PartName.Equals("Widget") ),
    Then = new If
    {
        // check if we have enough widgets in stock
        Condition = new InArgument<bool>( (e) => po.Get(e).Quantity < 100 ),
        Then = new SendReply
        {
            DisplayName = "Successful response",
            Request = submitPO,                                        
            Content = SendContent.Create(new InArgument<string>( (e) => string.Format("Success: {0} Widgets have been ordered!", po.Get(e).Quantity)) )
        },
        // if we don't have enough widgets, throw an unhandled exception from this operation's body
        Else = new Throw
        {
            Exception = new InArgument<Exception>((e) => new Exception("We don't have that many Widgets."))
        }
    },                        
    // if its not for widgets, reply to the client that we don't carry that part by sending back an expected fault type (POFault)
    Else = new SendReply
    {
        DisplayName = "Expected fault",
        Request = submitPO,
        Content = SendContent.Create(new InArgument<FaultException<POFault>>( (e) => new FaultException<POFault>(
            new POFault
            {
                Problem = string.Format("This company does not carry {0}s, but we do carry Widgets.", po.Get(e).PartName),
                Solution = "Try your local hardware store."
            },
            new FaultReason("This is an expected fault.")
            )))
    }
}

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

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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