Question

I’m getting mad with this piece of code:

for (int h = 0; h < invocations; h++)
{
    Filter newFilter = new Filter();
    newFilter = customFilter;
    newFilter.DateFrom = customFilter.DateFrom.AddDays(h*8);
    newFilter.DateTo = newFilter.DateTo.AddDays(8).AddSeconds(-1);

customFilter is an object of type Filter
customFilter is as an object which has about 10 properties inside it correctly filled. I need to create a new object but I’ve to change just two of these 10: DateFrom and DateTo.
The problem is that after the assignment of newFilter.DateFrom and newFilter.DateTo, also the customFilter.DateFrom and customFilter.DateTo change.
Could someone help me?

Bye
M.

Answer 1

newFilter simply a variable. I’m assuming Filter is a class; in which case, when you do this:

Filter newFilter = new Filter();
newFilter = customFilter;

you can forget about the new Filter() – you’ve just dropped that somewhere on the floor, inaccessible from anwhere: you have set newFilter to be a reference to the existing object, via the existing reference customFilter.

newFilter and customFilter are now references to the same object.

I suspect you just need to remove the line:

newFilter = customFilter;

leaving just:

Filter newFilter = new Filter();
// set all properties on newFilter

or make it cloneable:

Filter newFilter = customFilter.Clone();
// set just the properties that need changing on newFilter