Question

I have a data structure as follows: I have a list of objects with properties that i want to search for and then when i have found all the objects matching my search query, i want to update another property for all the found objects. Here is an example of the object’s properties:

Name: Sean Aston
City: Toronto
Eye Color: Blue
Warnings: 4

Name: Cole Anderson
City: New York City
Eye Color: Black
Warnings: 1

Name: Polly Smith
City: Toronto
Eye Color: Blue
Warnings: 3

My search woluld be select all those objects in the list whose properties eye color is blue and city is toronto. It should return me objects one and three. Then i should be able to update the warnings property of the first and third object to increment by 1.

How can i achieve this?
Thanks in advance.

Answer 1

To match your exact request would look like this:

foreach (var item in MyObjectList.Where(o => o.EyeColor == "Blue" && o.City == "Toronto"))
{
    item.Warnings ++;
}

But I suspect the criteria is entirely determined by the user, and so you don’t know what you’re looking for at compile time like this. In that case:

var search = (IEnumerable<MyObject>)MyObjectList;

if (!string.IsNullOrEmpty(txtCity.Text))
{
    search = search.Where(o => o.City == txtCity.Text);
}

if (!string.IsNullOrEmpty(txtEyeColor.Text))
{
    search = search.Where(o => o.EyeColor == txtEyeColor.Text);
}

// similar checks for name or warning level could go here

foreach(var item in search) {item.Warnings++;}