ValueTypeFieldReference<TOperand,TResult> Class

Definition

Namespace:

System.Activities.Expressions

Assembly:

System.Activities.dll

Represents a field on a value type that can be used as an l-value in an expression.

generic <typename TOperand, typename TResult>
public ref class ValueTypeFieldReference sealed : System::Activities::CodeActivity<System::Activities::Location<TResult> ^>

public sealed class ValueTypeFieldReference<TOperand,TResult> : System.Activities.CodeActivity<System.Activities.Location<TResult>>

type ValueTypeFieldReference<'Operand, 'Result> = class
    inherit CodeActivity<Location<'Result>>

Public NotInheritable Class ValueTypeFieldReference(Of TOperand, TResult)
Inherits CodeActivity(Of Location(Of TResult))

Type Parameters

TOperand

The value type.

TResult

The field type.

Inheritance

Object

Activity

ActivityWithResult

Activity<TResult>

CodeActivity<Location<TResult>>

ValueTypeFieldReference<TOperand,TResult>

Examples

The following code example uses ValueTypeFieldReference<TOperand,TResult> in an Assign activity to assign an integer value to a field and prints the field value to the console. The Assign activity is equivalent to the following statement when using the struct defined in the following example. myStructVariable.AField = 1;.

Note

Instead of instantiating the ValueTypeFieldReference<TOperand,TResult> l-value expression activity directly, it is strongly recommended that you call ConvertReference, which provides a higher level of abstraction and enables you to implement your workflow more intuitively.

// Define a struct with a field named AField.  
struct StructWithField  
{  
    public int AField;  
}  

public static void ValueTypeFieldReferenceSample()  
{  
    // Create a variable of type StructWithField to store the property.  
    var swfvar = new Variable<StructWithField>("swfvar", new StructWithField());  

    Activity myActivity = new Sequence  
    {  
        Variables = { swfvar },  
        Activities =   
        {                      
            // Create an Assign activity to assign a value to the AField field.  
            new Assign<int>  
            {  
                To = new ValueTypeFieldReference<StructWithField, int>()  
                {  
                    OperandLocation = swfvar,  
                    FieldName = "AField",  
                },  
                // Assign an integer value to AField.  
                Value = 1,  
            },  
            // Print the new field value to the console.  
            new WriteLine()  
            {  
                Text = ExpressionServices.Convert<string>(ctx => swfvar.Get(ctx).AField.ToString()),  
            }  
        }  
    };  

    // Invoke the Sequence activity.  
    WorkflowInvoker.Invoke(myActivity);  
}  

Constructors

ValueTypeFieldReference<TOperand,TResult>()

Initializes a new instance of the ValueTypeFieldReference<TOperand,TResult> class.

Properties

CacheId	Gets the identifier of the cache that is unique within the scope of the workflow definition. (Inherited from Activity)
Constraints	Gets a collection of Constraint activities that can be configured to provide validation for the Activity. (Inherited from Activity)
DisplayName	Gets or sets an optional friendly name that is used for debugging, validation, exception handling, and tracking. (Inherited from Activity)
FieldName	Gets or sets the name of the field.
Id	Gets an identifier that is unique in the scope of the workflow definition. (Inherited from Activity)
Implementation	Not supported. (Inherited from CodeActivity<TResult>)
ImplementationVersion	Gets or sets the implementation version of the activity. (Inherited from CodeActivity<TResult>)
OperandLocation	Gets or sets the instance of the value type that contains the field.
Result	Gets or sets the result argument for the Activity<TResult>. (Inherited from Activity<TResult>)
ResultType	When implemented in a derived class, gets the type of an activity OutArgument. (Inherited from ActivityWithResult)

Methods

CacheMetadata(ActivityMetadata)	Not implemented. Use CacheMetadata(CodeActivityMetadata) instead. (Inherited from CodeActivity<TResult>)
CacheMetadata(CodeActivityMetadata)	Creates and validates a description of the activity's arguments, variables, child activities, and activity delegates. (Inherited from CodeActivity<TResult>)
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
Execute(CodeActivityContext)	When implemented in a derived class, performs the execution of the activity. (Inherited from CodeActivity<TResult>)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
OnCreateDynamicUpdateMap(UpdateMapMetadata, Activity)	Raises an event when creating a map for the dynamic update. (Inherited from CodeActivity<TResult>)
ShouldSerializeDisplayName()	Indicates whether the DisplayName property should be serialized. (Inherited from Activity)
ToString()	Returns a String that contains the Id and DisplayName of the Activity. (Inherited from Activity)