Forum Discussion

hrothrock's avatar
hrothrock
Contributor
5 years ago

lazy loading - objects not yet in memory

I am working with an application that uses lazy loading. In one of my tests, I am accessing a row that is visible on a normal monitor. Today I am working on my small laptop and the row is not only no...
  • tristaanogre's avatar
    tristaanogre
    5 years ago

    FindChild by itself still won't overcome the lazy-load... that's why my PseudoCode had the PageDown call in a while loop.  I'd re-write your code as follows.

     

    function findRow()
{
var Row = 8;
var List = Aliases.pageDispatch.ListDispatchJobs;
var child = List.FindChild("Name", "Panel(" + (Row -1) + ")", 1, true);
while (!child.Exists) {
    List.Keys("[PageDown]");
    child = List.FindChild("Name", "Panel(" + (Row -1) + ")", 1, true);
}
Log.Message(child.contentText);
}

    This will check to see if the child exists.  If not, it sends a page down keystroke to scroll the list and then checks again.  When it does exist, it exits the while loop and the child object is now the desired object.

hrothrock's avatar
hrothrock
Contributor

tristaanogre :

 

Thanks for the reply. Here is what I was trying before:

 

function GridCellCheckboxClick(List, Row, Column)
{
   var Row = List.Panel(Row - 1).Panel(0);
   if (! (Row.Exists = true))

       {

           Row.scrollIntoViewIfNeeded();

        }
}

 

Unnecessary parts of the function were removed. I knew I would need to clean up my if statement but because the row was not even in memory yet it was failing on the declaration of the variable, which is where I think your suggestion might also fail.

tristaanogre's avatar
tristaanogre
Esteemed Contributor
5 years ago

My code was pseudcode, by no means fully fleshed out or tested. It was intended to present concept.

 

So, basically, replace you "ScrollIntoView" with sending a PageDown keystroke to the table that needs to scroll.  Then write some code to check to see if the desired row is on screen.  FindChild works well for this.  It will return a stub object with Exists = false if not found or it will return an actual object which you can then return as the result of the function if so desired.  

  • tristaanogre's avatar
    tristaanogre
    Esteemed Contributor
    5 years ago

    Just as a note, your test for "Row Exists" will fail immediately because if the object does not exist, how can you test the value of the property of the non-existing object?  ALWAYS, when testing for "existence", you should use a method that will return some object with the Exists property.  FindChild, FindChildren, WaitChild, WaitAliasChild, etc., will all return a "stub" with the Exists property as false.  Your code COULD work if you replace that logic and replace the ScrollIntoView with a PageDown.

    • hrothrock's avatar
      hrothrock
      Contributor
      5 years ago

      tristaanogre 

      I have been experimenting with the find child (which i have used successfully in other places) and it will not return a stub object. Maybe I am using it incorrectly. Here is my code:

       

      function findRow()
      {
      var Row = 8;
      var List = Aliases.pageDispatch.ListDispatchJobs;
      var child = List.FindChild("Name", "Panel(" + (Row -1) + ")", 1, true);
      Log.Message(child.contentText);
      }

       

      Row 7 does not exist yet as I haven't scrolled that far. If I run it without the Log.Message line, it passes with no details at all. With the Log.Message, I get this message: "The object does not exist. See details..." and the details say "You are trying to call the "contentText' method or property of an object that does not exist." It does not give me a stub object. I also tried entering a row number that does exist and it returned the correct content text.

      • tristaanogre's avatar
        tristaanogre
        Esteemed Contributor
        5 years ago

        FindChild by itself still won't overcome the lazy-load... that's why my PseudoCode had the PageDown call in a while loop.  I'd re-write your code as follows.

         

        function findRow()
{
var Row = 8;
var List = Aliases.pageDispatch.ListDispatchJobs;
var child = List.FindChild("Name", "Panel(" + (Row -1) + ")", 1, true);
while (!child.Exists) {
    List.Keys("[PageDown]");
    child = List.FindChild("Name", "Panel(" + (Row -1) + ")", 1, true);
}
Log.Message(child.contentText);
}

        This will check to see if the child exists.  If not, it sends a page down keystroke to scroll the list and then checks again.  When it does exist, it exits the while loop and the child object is now the desired object.