I have an if that checks for a querystring,
If this equals "All" then collect everything into rep collection,
If this equals (A certain item collection name) then collect only those that match into rep collection,
Then do a for loop for the amount of items in the collection,
Then do foreach for each item in collection.

Because I'm declaring the var rep inside an if statement, it's saying rep does not exist when I get to the for loop. I have tried to declare it outside (and from what I've read, this is considered anti-C#), but now I'm stuck.

Any help, greatly appreciated.

@using umbraco.MacroEngines
@inherits umbraco.MacroEngines.DynamicNodeContext

string collect = String.Format("{0}", Request.QueryString["QueryName"]);
      
if (!string.IsNullOrEmpty(Request.QueryString["QueryName"])) {
   if (collect == "All") {
        var rep = CurrentModel.DescendantsOrSelf().Items.SingleOrDefault();
   } else {
      var rep = CurrentModel.DescendantsOrSelf().Items.SingleOrDefault(x => x.Name == collect);
  }
          
   int i;
 for (i = 0; i < rep.Children.Count() / numInRow; i++) {
        // for loop required for positioning purposes        
       foreach (var node in rep.Children) {
            //do stuff with each node
        }
    }
}