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Activity<TResult> Class

An abstract base class used to create composite activities from pre-existing Activity objects, which specifies a result type using the activity’s type specifier.

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

[TypeConverterAttribute(typeof(ActivityWithResultConverter))]
public abstract class Activity<TResult> : ActivityWithResult

Type Parameters

TResult

The type of the return value of the activity.

The Activity<TResult> type exposes the following members.

  NameDescription
Protected methodActivity<TResult>When implemented in a derived class, creates a new instance of the derived class.
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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.)
Protected propertyConstraintsGets a collection of Constraint activities that can be configured to provide validation for the Activity. (Inherited from Activity.)
Public propertyDisplayNameGets or sets an optional friendly name that is used for debugging, validation, exception handling, and tracking. (Inherited from Activity.)
Public propertyIdGets an identifier that is unique in the scope of the workflow definition. (Inherited from Activity.)
Protected propertyImplementationGets or sets the delegate that returns an Activity that contains the execution logic. (Inherited from Activity.)
Protected propertyImplementationVersionGets or sets the version of the implementation used. (Inherited from Activity.)
Public propertyResultGets or sets the result argument for the Activity<TResult>.
Public propertyResultTypeWhen implemented in a derived class, gets the type of an activity OutArgument. (Inherited from ActivityWithResult.)
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  NameDescription
Protected methodCacheMetadataCreates and validates a description of the activity’s arguments, variables, child activities, and activity delegates. (Inherited from Activity.)
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodStatic memberFromValueReturns a Activity<TResult> expression that evaluates to the given value.
Public methodStatic memberFromVariable(Variable)Returns a Activity<TResult> expression that evaluates to the given Variable.
Public methodStatic memberFromVariable(Variable<TResult>)Returns a Activity<TResult> expression that evaluates to the given Variable<T>.
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Protected methodOnCreateDynamicUpdateMapRaises an event when creating dynamic update map. (Inherited from Activity.)
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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  NameDescription
Public operatorStatic memberImplicit(TResult to Activity<TResult>)Returns a Activity<TResult> expression that evaluates to the given value.
Public operatorStatic memberImplicit(Variable to Activity<TResult>)Returns a Activity<TResult> expression that evaluates to the given Variable.
Public operatorStatic memberImplicit(Variable<TResult> to Activity<TResult>)Returns a Activity<TResult> expression that evaluates to the given Variable<T>.
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Activity<TResult> is the base class in the activity type hierarchy. All other activity types with generic type definitions such as CodeActivity<TResult>, NativeActivity<TResult>, AsyncCodeActivity<TResult>, and DynamicActivity<TResult> derive from this class.

The following example shows how to derive a class from Activity<TResult>.

public sealed class AppendString : Activity<string>
{
    // Input argument.
    [RequiredArgument]
    public InArgument<string> Name { get; set; }

    public AppendString()
    {
        // Define the implementation of this activity. 
        this.Implementation = () => new Assign<string>
        {
            Value = new LambdaValue<string>(ctx => Name.Get(ctx) + " says hello world"),
            To = new LambdaReference<string>(ctx => Result.Get(ctx)),
        };
    }
}

.NET Framework

Supported in: 4.5, 4

.NET Framework Client Profile

Supported in: 4

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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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