Search function with unknown indata

Question

Hello everyone! I'd like to make a search function that takes indata from 5 textboxes, Name, gender,ID, animal category and animal. The diffrances between animal category and animal is for eg. animal category = mammal and animal = bear. So these are optional to the user, when he/she hits the button it should search for the given parameters. The data is saved in an genereic list with the Animal type. eg. ListanimalCollection

I tried to use linq, my query ->

    ienumerable<Animal> result= 
    from a in animalCollection where a.Name== myParameterName
    &&
    a.Gender == myParameterGender
    select a;

the problem comes to when user wants to have one or more than two parameters cus i don't know how to make the query depending on user input. Do i have to make a bunch of if-statements to check user input? I hope there is another way!

Im asking you smart experts for help with this! Hope i made myself clear enough.

Daniel, sweden

Answer 1

Assuming that your parameters are all strings then you could do something like this:

var result = from a in animalCollection
             where (string.IsNullOrEmpty(myParameterName) || a.Name == myParameterName)
                && (string.IsNullOrEmpty(myParameterGender) || a.Gender == myParameterGender)
                && (string.IsNullOrEmpty(myParameterID) || a.ID == myParameterID)
                && (string.IsNullOrEmpty(myParameterCategory) || a.Category == myParameterCategory)
                && (string.IsNullOrEmpty(myParameterAnimal) || a.Animal == myParameterAnimal)
             select a;