internal static bool TryMorphExpression(ActivityWithResult originalExpression, bool isLocation, Type targetType,
EditingContext context, out ActivityWithResult morphedExpression)
{
bool succeeded = false;
morphedExpression = null;
if (originalExpression != null)
{
Type resultType = originalExpression.ResultType;
if ((isLocation) && (ExpressionHelper.IsGenericLocationExpressionType(originalExpression) && (targetType == resultType.GetGenericArguments()[0])) ||
(!isLocation) && (resultType == targetType))
{
//no need to morph
succeeded = true;
morphedExpression = originalExpression;
}
else
{
Type expressionType = originalExpression.GetType();
if (expressionType.IsGenericType)
{
expressionType = expressionType.GetGenericTypeDefinition();
}
ExpressionMorphHelperAttribute morphHelperAttribute = ExtensibilityAccessor.GetAttribute <ExpressionMorphHelperAttribute>(expressionType);
if (morphHelperAttribute != null)
{
ExpressionMorphHelper morphHelper = Activator.CreateInstance(morphHelperAttribute.ExpressionMorphHelperType) as ExpressionMorphHelper;
if (morphHelper != null)
{
succeeded = morphHelper.TryMorphExpression(originalExpression, isLocation, targetType, context, out morphedExpression);
if (succeeded && morphedExpression != null)
{
string editorName = ExpressionActivityEditor.GetExpressionActivityEditor(originalExpression);
if (!string.IsNullOrWhiteSpace(editorName))
{
ExpressionActivityEditor.SetExpressionActivityEditor(morphedExpression, editorName);
}
}
}
}
}
}
else
{
succeeded = true;
}
return(succeeded);
}
// this method may has side effect, it may modify model.
internal static bool TryInferReturnType(ActivityWithResult expression, EditingContext context, out Type returnType)
{
bool succeeded = false;
returnType = null;
Type expressionType = expression.GetType();
if (expressionType.IsGenericType)
{
expressionType = expressionType.GetGenericTypeDefinition();
ExpressionMorphHelperAttribute morphHelperAttribute = ExtensibilityAccessor.GetAttribute <ExpressionMorphHelperAttribute>(expressionType);
if (morphHelperAttribute != null)
{
ExpressionMorphHelper morphHelper = Activator.CreateInstance(morphHelperAttribute.ExpressionMorphHelperType) as ExpressionMorphHelper;
if (morphHelper != null)
{
succeeded = morphHelper.TryInferReturnType(expression, context, out returnType);
}
}
}
return(succeeded);
}
