static bool TryEvaluateExpression(
string expressionString,
Type locationValueType, // Non null for Reference type (location)
LocationReferenceEnvironment locationReferenceEnvironment,
CodeActivityContext context,
out object result)
{
expressionString = string.Format(CultureInfo.InvariantCulture, "[{0}]", expressionString);
Type activityType;
if (locationValueType != null)
{
activityType = typeof(Activity <>).MakeGenericType(typeof(Location <>).MakeGenericType(locationValueType));
}
else
{
activityType = typeof(Activity <object>);
}
// General expression.
ActivityWithResultConverter converter = new ActivityWithResultConverter(activityType);
ActivityWithResult expression = converter.ConvertFromString(
new TypeDescriptorContext {
LocationReferenceEnvironment = locationReferenceEnvironment
},
expressionString) as ActivityWithResult;
if (locationValueType != null)
{
Type locationHelperType = typeof(LocationHelper <>).MakeGenericType(locationValueType);
LocationHelper helper = (LocationHelper)Activator.CreateInstance(locationHelperType);
return(helper.TryGetValue(expression, locationReferenceEnvironment, context, out result));
}
else
{
return(TryEvaluateExpression(expression, locationReferenceEnvironment, context, out result));
}
}