Personally, I'd just go with an extension that parses to nullable double: I agree that a nullable double is a neat way of representing it, but if the code annoys you so then try something different (a bool, for example: discount_given = true). You're just going to have to write the ugly code with a local non-nullable type or use another way of defining that there's no discount. If (Double.TryParse(txtDiscount.Text, out value))Įrrors.Add('Discount must be a double.') // discount will have null valueīut I'd moved all this logic to extension. If (!String.IsNullOrEmpty(txtDiscount.Text)) You can do parsing without extension method - just use local non-nullable value to pass it to TryParse method: So how can I deal with this situation without using extension method? But I actually don't like the code above, it seems to me pretty complicated for such a task but I can't think of something better. If (!double.TryParse(txtDiscount.Text, out _discount))Īnd then use my nullable discount to pass the value to the database. What I can think of is using another variable like so : I saw that many people are making extensions for this type of situations but for now I don't think it's necessary. So I get an error for invalid argument and obviously it's the discount which can not be nullable if I'm gonna use it in TryParse. If (!double.TryParse(txtDiscount.Text, out discount)) errors.Add('Discount must be a double.')

If (!string.IsNullOrEmpty(txtDiscount.Text)) On the back end I want to save the data so for now I have this: How to use double.TryParse when the output is allowed to be null? - c# In my application I have a textbox - txtDiscount where the admin can set a discount percentage for a certain user, or he may not.

Flash actionscript 3.0 tryparse