Switch<T> Class

.NET Framework (current version)

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Selects one choice from a number of activities to execute, based on the value of a given expression of the type specified in this object’s type specifier.

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


generic<typename T>
public ref class Switch sealed : NativeActivity

Type Parameters


The type of the values provided in the Cases collection.


Creates a new instance of the Switch<T> class.


Creates a new instance of the Switch<T> class with the specified expression.

System_CAPS_pubmethodSwitch<T>(Expression<Func<ActivityContext^, T>^>^)

Creates a new instance of the Switch<T> class with the specified expression.


Creates a new instance of the Switch<T> class with the specified expression.


Gets the identifier of the cache that is unique within the scope of the workflow definition.(Inherited from Activity.)


Represents the dictionary of potential execution paths. Each entry contains a key and an activity that is executed when the result of the expression matches the key.


Represents the activity that is executed if no keys of entries in the P:System.Activities.Statements.Switch.Cases collection match the P:System.Activities.Statements.Switch.Expression property.


Gets or sets an optional friendly name that is used for debugging, validation, exception handling, and tracking.(Inherited from Activity.)


Gets the object to compare to the keys in the P:System.Activities.Statements.Switch.Cases collection.


Gets an identifier that is unique in the scope of the workflow definition.(Inherited from Activity.)


Gets or sets the implementation version of the activity.(Inherited from NativeActivity.)


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.)


Indicates whether the DisplayName property should be serialized.(Inherited from Activity.)


Returns a String that contains the Id and DisplayName of the Activity.(Inherited from Activity.)

Each case in the Cases dictionary consists of a value (serving as the key for the dictionary) and an activity (serving as the value for the dictionary). The P:System.Activities.Statements.Switch.Expression is evaluated and compared against the keys in the Cases dictionary. If a match is found, the corresponding activity is executed. Every key in the Cases dictionary must be unique according to the dictionary’s equality comparer.

The following code sample demonstrates creating a Switch<T> activity. This example is from the Using Procedural Activities sample.

// check if the number is ok...
new Switch<int>()
    DisplayName = "Verify Value from User",
    Expression = ExpressionServices.Convert<int>( env => numberFromUser.Get(env).CompareTo(numberToGuess.Get(env)) ),
    Cases = 
        { 0, new Assign<bool>()
                To = new OutArgument<bool>(finished),
                Value = true
        {  1, new WriteLine() { Text = "    Try a lower number number..." } }, 
        { -1, new WriteLine() { Text = "    Try a higher number" } }

.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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