ValueTypeFieldReference<TOperand, TResult> Class
Represents a field on a value type that can be used as an l-value in an expression.
System.Activities::Activity
System.Activities::ActivityWithResult
System.Activities::Activity<Location<TResult>>
System.Activities::CodeActivity<Location<TResult>>
System.Activities.Expressions::ValueTypeFieldReference<TOperand, TResult>
Assembly: System.Activities (in System.Activities.dll)
The ValueTypeFieldReference<TOperand, TResult> type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | ValueTypeFieldReference<TOperand, TResult> | Initializes a new instance of the ValueTypeFieldReference<TOperand, TResult> class. |
| Name | Description | |
|---|---|---|
![]() | 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>.) |
![]() | 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.) |
| Name | Description | |
|---|---|---|
![]() | 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 | When implemented in a derived class, performs the execution of the activity. (Inherited from CodeActivity<TResult>.) |
![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() | GetHashCode | Serves as a hash function for a particular type. (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.) |
![]() | 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.) |
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<TResult>(Expression<Func<ActivityContext, TResult>>), 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);
}
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
