ActivityValidator.Validate(ValidationManager, Object) Method

Definition

Namespace:

System.Workflow.ComponentModel.Compiler

Assembly:

System.Workflow.ComponentModel.dll

Verifies that the given activity is valid.

public:
 override System::Workflow::ComponentModel::Compiler::ValidationErrorCollection ^ Validate(System::Workflow::ComponentModel::Compiler::ValidationManager ^ manager, System::Object ^ obj);

public override System.Workflow.ComponentModel.Compiler.ValidationErrorCollection Validate (System.Workflow.ComponentModel.Compiler.ValidationManager manager, object obj);

override this.Validate : System.Workflow.ComponentModel.Compiler.ValidationManager * obj -> System.Workflow.ComponentModel.Compiler.ValidationErrorCollection

Public Overrides Function Validate (manager As ValidationManager, obj As Object) As ValidationErrorCollection

Parameters

manager

ValidationManager

The ValidationManager associated with validation.

obj

Object

The Activity to be validated.

Returns

ValidationErrorCollection

A ValidationErrorCollection object that contains any errors or warnings that occurred during validation.

Examples

The following example shows how to override the Validate method for an ActivityValidator used for a custom activity that has a single dependency property named Msg of type String. The custom validator ensures that the Msg property is set. If it is not set, the compiler displays an error when the Validate method is called on the ActivityValidator and the compilation fails.

public override ValidationErrorCollection Validate(ValidationManager manager, object obj)
{
    // Invoke the base class method implementation to
    // perform default validation.
    ValidationErrorCollection errors = base.Validate(manager, obj);

    // Make sure there is an activity instance.
    ConsoleWriteLineActivity crw = obj as ConsoleWriteLineActivity;
    if (crw == null)
    {
        throw new InvalidOperationException();
    }

    // If the activity has no parent then this validation
    // is occurring during the compilation of the activity
    // and not during the hosting or creation of an
    // activity instance.
    if (crw.Parent == null)
    {
        // Can skip the rest of the validation because
        // it deals with the hosting and the creation
        // of the activity.
        return errors;
    }

    // Msg is required. Add a validation error if there is no
    // Msg specified or Msg is not bound to another property.
    if (string.IsNullOrEmpty(crw.Msg) &&
        crw.GetBinding(ConsoleWriteLineActivity.MsgProperty) == null)
    {
        errors.Add(new ValidationError("Msg is required", 100, false, "Msg"));
    }

    return errors;
}

Public Overrides Function Validate( _
    ByVal manager As System.Workflow.ComponentModel.Compiler.ValidationManager, _
    ByVal obj As Object) As System.Workflow.ComponentModel.Compiler.ValidationErrorCollection

    'Invoke the base class method implementation to
    'perform default validation.
    Dim errors As ValidationErrorCollection = MyBase.Validate(manager, obj)

    'Make sure there is an activity instance.
    Dim crw As ConsoleWriteLineActivity = CType(obj, ConsoleWriteLineActivity)
    If crw Is Nothing Then
        Throw New InvalidOperationException()
    End If

    'If the activity has no parent then this validation
    'is occurring during the compilation of the activity
    'and not during the hosting or creation of an
    'activity instance.
    If crw.Parent Is Nothing Then
        'Can skip the rest of the validation because
        'it deals with the hosting and the creation
        'of the activity.
        Return errors
    End If

    'Msg is required. Add a validation error if there is no
    'Msg specified or Msg is not bound to another property.
    If String.IsNullOrEmpty(crw.Msg) And _
        crw.GetBinding(ConsoleWriteLineActivity.MsgProperty) Is Nothing Then

        errors.Add(New ValidationError("Msg is required", 100, False, "Msg"))

    End If

    Return errors
End Function

Remarks

This method calls ValidateProperties to validate the properties of the Activity.

This method only validates the uniqueness of the Name for the Activity if the Activity is not a root Activity.