![xojo weblistbox xojo weblistbox](http://celestialfantasy.weebly.com/uploads/1/2/4/1/124198768/811908079.png)
#Xojo weblistbox code#
To make sure there isn’t a blank space in the UI while it is invisible, an identical blank Listbox can be put behind the Listbox in use, or a “please wait” image can be used instead, but you have to remember that the window may be resizable and the list may be resized too.Īnd don’t forget to use the Xojo Profiler to check your code performance when you see it needs some work. This is not necessary for most uses, but if you are populating a Listbox with a very large amount of data, this can bring a big performance improvement.
![xojo weblistbox xojo weblistbox](https://forum.xojo.com/uploads/default/original/2X/9/922e3ccd6382e6a524a08ae3abb06fb8e134552e.jpeg)
Although it is not as fast as the single line of code to add the row, it is still much faster than adding a blank row and then populating each cell one by one.Īnother tip is to make a Listbox invisible while rows are being added, and visible again when it is ready. This makes the code easier to read and edit. Take the following example, which may look familiar: If we can reduce inefficiencies in loop code, we can make significant performance improvements. Loops are used to repeat blocks of code over and over again. …you can store values in variables first: And if you don’t want long and hard to read lines of code like this… MyListbox.AddRow rs.Field(âvalue1â).StringValue, _ For a WebListbox on a WebPage it is a very noticeable difference. If your lists are long and have several columns you will see a difference. This works significantly faster and is less code to write. This is inefficient and can be improved by adding the entire row to the list in one go: MyListbox.Cell(MyListbox.LastIndex,3) = z MyListbox.Cell(MyListbox.LastIndex,2) = y MyListbox.Cell(MyListbox.LastIndex,1) = x MyListbox.Cell(MyListbox.LastIndex,0) = w I often see code like this to add rows to Listboxes: MyListbox.AddRow " " If you have a feature that processes a large volume of data, and various different methods get called from inside a loop, flattening the code would help improve performance. If the code within the CalculateTotals method were put directly into our loop instead, 5,000 calls to the method would be eliminated, so the loop code would run faster. In our tiny example above, the CalculateTotals method gets called 5,000 times. Xojo is great for building structured code using methods, but we can speed things up in a loop by reducing the number of calls to methods. If our Listbox had 5,000 rows, the loop would calculate this same value 5,000 times! We get improved performance by calculating it only once: Dim n As Integer = MyListbox.ListCount - 1 // or MyPopupMenu.ListCount-1 Here the For loop is calculating the value of (MyListbox.ListCount – 1) each time it goes around the loop. Also works with MyPopupMenu.ListCount-1įor i As Integer = 0 to MyListbox.ListCount - 1