Question

Given the following two cases, which one is preferable (If they’re both bad, doing it a completely different way is an option too)?

Convert.ToInt32 called in Where:

 var items = GetItems();
 if (aDropDownList.SelectedIndex > 0) 
 {
     items = items.Where(x => 
             x.IntProperty == Convert.ToInt32(aDropDownList.SelectedValue));
 }

Convert.ToInt32 called before Where:

var items = GetItems();
 if (aDropDownList.SelectedIndex > 0) 
 {
     int selectedDropDownValue = Convert.ToInt32(aDropDownList.SelectedValue);
     items = items.Where(x => x.IntProperty == selectedDropDownValue);
 }

Answer 1

I would prefer the second. It does only one conversion, instead of many.

But unless this is a performance-critical piece of code (unlikely; it seems like GUI code), you won’t notice a difference.