I have report view where a bunch of controls located, there is an example code:
#Html.DevExpress().DropDownEdit(
settings =>{
settings.Name = "SomeList";
settings.Width = 100;
settings.SetDropDownWindowTemplateContent(c =>{
#Html.DevExpress().ListBox(
...
).BindList(ViewData["SomeList"]).Render();
some code...
).GetHtml()
When it render first time it works fine, but in business logic there is another drop down let's call it dropdown #2. When user select some values in dropdown#2 JS handle this action send request to the server to get actual value for first dropdown, then clear all rendered values from dropdown #1 and insert new items.
And problem in performance lies in how devexpress create new items on client side. From backend there is now 8000 new items can be added to dropdown #1 and it keep growing. And user must wait 5-10 seconds when browser render it. I tried to research what is happening when new item is creating but there are a lot of devexpress function which call another functions.
JS code look's like:
SomeList.BeginUpdate();
l = data.SomeList.length;
while (x < l) {
SomeList.AddItem(data.SomeList[x].Name, data.SomeList[x].Id);
x++;
}
SomeList.EndUpdate();
BeginUpdate and EndUpdate is devexpress functions that prohibbit browser render control while adding new items. Without this function it takes eternity to finish adding new items.
I know start point of problem it is - item creating code SomeList.AddItem(...).
So my question: is there way to do something like console.trace(SomeList.AddItem(...)) and see full trace which will be executed on first code pass?
Also is there way to determine which function call take alot of time to execute?
Related
I have an Angular 4 application in which I need to add the following functionality:
There is a component with a list of objects. When the user double clicks on one of them, the app retrieves from a DB a list of objects and it should scroll to where the object appears.
I'd like to know how I could move to the desired position in the data once that it has been displayed in the browser. Right now, I have the following code:
let objElement = document.querySelector("#object_"+searchItem._objectID);
if (objElement){
objElement.scrollIntoView();
console.log("****** SCROLLING TO OBJECT");
}
The problem is that, the first time that I load the data from the DB, it seems that 'document.querySelector' returns null, as if the HTML wasn't 100% constructed yet, so it doesn't scroll to the position. If I try to locate the element again, it scrolls perfectly (as it doesn't reload the data from the DB).
Is there a "more Angular" way of doing this? I'm trying to find an example like this in the Angular Router documentation but I can't find anything...
EDIT:
To make things clearer, this is the pseudo-code that I run when the user selects an object:
if(selectedObject IS IN currentLoadedObjects) {
scrollTo(selectedObject); // This function runs the code above
}
else { // The object is in a different list, so retrieve it from the DB
ObjectService.getObjectListFromDB(selectedObject)
.subscribe((returnedList) => {
displayObjectList(returnedList); // Basically, this function parses the returned data, which is displayed in the template using an *ngFor loop
scrollTo(selectedObject);
});
}
As you can see, I try to scroll to the object inside the 'subscribe' method, once that I have the data from the database and after I've parsed it. The object list is pretty big, so it takes 1-2 seconds to be displayed in the browser.
Thanks!
I have a not too big grid (30x20) with numbers in cells. I have to display all, calculate them in different ways (by columns, rows, some cells, etc.) and write values to some cells. This data is also written and read from db table fields. Everything is working, excluding simple (theoretically) mask tools.
In time of e.g. writing data to the field in the table I try to start mask and close it on finish. I used such a “masks” very often but only in this situation I have a problem and can’t solve it.
I prepare this mask the following way:
msk = new Ext.LoadMask(Ext.getBody(), { msg: "data loading ..." });
msk.show();
[writing data loops]
msk.hide();
msk.destroy();
I also tried to use grid obiect in place of Ext.getBody(), but without result.
I found also that the program behaves in a special way – loops which I use to write data to the table field are "omitted" by this mask, and it looks like loops are working in the background (asynchronously).
Would you be so kind as to suggest something?
No, no, no, sorry guys but my description isn’t very precise. It isn’t problem of loading or writing data to the database. Let’s say stores are in the memory but my problem is to calculate something and write into the grid. Just to see this values on the screen. Let me use my example once again:
msk = new Ext.LoadMask(Ext.getBody(), { msg: "data loading ..." });
msk.show();
Ext.each(dataX.getRange(), function (X) {
Ext.each(dataY.getRange(), function (Y) {
…
X.set('aaa', 10);
…
}
msk.hide();
msk.destroy();
And in such a situation this mask isn’t visible or is too fast to see it.
In the mean time I find (I think) a good description of my problem but still can’t find a solution for me. When I use e.g. alert() function I see this mask, when I use delay anyway, mask is too fast. Explanation is the following:
The reason for that is quite simple - JS is single threaded. If you modify DOM (for example by turning mask on) the actual change is made immediately after current execution path is finished. Because you turn mask on in beginning of some time-consuming task, browser waits with DOM changes until it finishes. Because you turn mask off at the end of method, it might not show at all. Solution is simple - invoke store rebuild after some delay.*
I have no idea how is your code looks in general but this is some tip that you could actually use.
First of all loading operations are asynchronously so you need to make that mask show and then somehow destroy when data are loaded.
First of all check if in your store configuration you have autoLoad: false
If yes then we can make next step:
Since Extjs is strongly about MVC design pattern you should have your controller somewhere in your project.
I suppose you are loading your data on afterrender or on button click event so we can make this:
In function for example loadImportantData
loadImportantData: function(){
var controller = this;
var store = controller.getStore('YourStore'); //or Ext.getStore('YourStore'); depends on your configuration in controller
var myMask = new Ext.LoadMask(Ext.getBody(), {msg:"Please wait..."});
myMask.show();
store.load({
callback: function (records, operation, success) {
//this callback is fired when your store load all data.
//then hide mask.
myMask.hide();
}
});
}
When data is loaded your mask will disappear.
If you have a reference to the grid, you can simply call grid.setLoading(true) to display a loading mask over the grid at any time.
I was asked to develop a tab panel with 6 tabs, each having 30 to 40 elements. Each tab is acting as a form in accumulating the details of a person and the last tab is a Summary page which displays all the values entered in the first five tabs. I was asked to provide summary as a tab because, the user can navigate to summary tab at any instance and look at the details entered by him/ or glace the summary. i am following ExtJs MVC pattern. Payload is coming from / going to Spring MVC Application. (JSON)
Using tab change event in controller and if the newtab is summary I am rendering the page with show hide functionality.
Method 1 :In controller I have used Ext.getCmp('id of each element inside the tabs') and show hide the components in summary tab based on the value entered by the user. This killed my app in IE8 popping a message saying that the "script is slow and blah blah..." i had to click on NO for 5 to 6 times for the summary tab to render and display the page.
Method 2 :In controller I used ref and selectos to acccess all the items in tabs. I have used itemId for each and every field in summary tab. like this.getXyz().show(). I thought it would be fast. Yes it was in Google chrome. but my app in IE8 is slow compared to goolge chrome/firefox
Any suggestions regarding this and plan to decrease page render time. The summary page has more than 1000 fields. Please feel free to shed ur thoughts or throw some ideas on this.
thank you!!
I've got a few suggestions you can try. First, to answer your title, I think the fastest simple way to lookup components in javascript is to build a hash map. Something like this:
var map = {};
Ext.each(targetComponents, function(item) {
map[item.itemId] = item;
});
// Fastest way to retrieve a component
var myField = map[componentId];
For the rendering time, be sure that the layout/DOM is not updated each time you call hide or show on a child component. Use suspendLayouts to do that:
summaryTabCt.suspendLayouts();
// intensive hide-and-seek business
// just one layout calculation and subsequent DOM manipulation
summaryTabCt.resumeLayouts(true);
Finally, if despite your best efforts you can't cut on the processing time, do damage control. That is, avoid freezing the UI the whole time, and having the browser telling the user your app is dead.
You can use setTimeout to limit the time your script will be holding the execution thread at once. The interval will let the browser some time to process UI events, and prevent it from thinking your script is lost into an infinite loop.
Here's an example:
var itemsToProcess = [...],
// The smaller the chunks, the more the UI will be responsive,
// but the whole processing will take longer...
chunkSize = 50,
i = 0,
slice;
function next() {
slice = itemsToProcess.slice(i, i+chunkSize);
i += chunkSize;
if (slice.length) {
Ext.each(slice, function(item) {
// costly business with item
});
// defer processing to give time
setTimeout(next, 50);
} else {
// post-processing
}
}
// pre-processing (eg. disabling the form submit button)
next(); // start the loop
up().down().action....did the magic. I have replaced each and every usage of Ext.getCmp('id'). Booooha... it's fast and NO issues.
this.up('tabpanel').down('tabName #itemIdOfField').actions.
actions= hide(), show(), setValues().
Try to check deferredRender is true. This should only render the active tab.
You also can try a different hideMode. Especially hideMode:'offsets ' sounds promising
Quote from the sencha API:
hideMode: 'offsets' is often the solution to layout issues in IE specifically when hiding/showing things
As I wrote in the comment, go through this performance guide: http://docs.sencha.com/extjs/4.2.2/#!/guide/performance
In your case, this will be very interesting for you:
{
Ext.suspendLayouts();
// batch of updates
// show() / hide() elements
Ext.resumeLayouts(true);
}
I need to do a simple pdf with some 3D objects for an oral presentation. I made several views, each one with a camera viewpoint, an object and a display mode.
To avoid the need to manually switch between the different viewpoints with the context menu, I would like the viewpoints to switch automatically with a Timer (each viewpoint staying for a few seconds). And I would like to not have to touch the mouse at all (nor the keyboard), so I would like to have the playback started as soon as the page appears.
I found the javascript command runtime.setView(N,x) to switch to the x'th view among N, but I don't know where to put it (I don't want to define a function which will be called when I press a button, since I want everything to be automated). Also, I don't know how to pause for a few seconds.
Any help ? Thanks !
I believe you're looking for setInterval(fn, time) which will call a function periodically at a time interval that you set. I'm not familiar with the setView() method you mentioned, but here's some pseudo code that you would put in tags at the end of the document body.
function startSwitcher()
var viewNum = 0;
var maxViews = 5; // you set this to how many views there are
setInterval(function() {
++viewNum;
if (viewNum >= maxViews) {
viewNum = 0;
}
runtime.setView(N, viewNum); // you will have to figure out this line
}, 2000);
}
startSwitcher();
The 2000 is 2000 milliseconds and is the time interval between executing the function. You can put any number of milliseconds there.
The runtime.setView(N, viewNum) line is something you will have to figure out as I am not familiar with whatever library you're trying to use there. The operative part of this code is the viewNum variable which configures which view in rotation should be next.
I think the runtime.SetView(..) Methods works with the name of the view as a string instead of the viewnumber. I have this function in a Dokument-level script and it works for me:
// view is the name of the view for example "TopView"
function setView(view){
console.println("Navigating to view: "+view);
var pageIndex = this.pageNum;
var annotIndex = 0;
var c3d = this.getAnnots3D( pageIndex )[ annotIndex ].context3D;
c3d.runtime.setView(view, true);
}
Combine this with the setInterval(..) from jfriend00´s answer und you should get what you need.
Best regards
I have a html page with 2 buttons on it and a big javascript function that is executed every 10 ms. Each click on each button executes a javascript function that changes some variables used by the big javascript function and change its behaviour. In time the code got very complex and time consuming and I would like to move the entire calculation of variables over to the server side. Or, better yet I would like to generate the entire function on the server.
How can I dynamically change the big javascript function when any of the 2 buttons is being pressed?
What you could do is once the button is pressed you make an Ajax request to the server side. There you generate the javascript code based on the button pressed and send it back. You can then eval the response and execute the appropriate function.
Grabbing a large script and executing it every 10 ms is bound to be slow.
Modifying a large script isn't that bad and then you only care about the execution plan of the script. (It doesn't matter how fast the server can generate the script the client will execute if you're sending it every 10 ms and it's super complicated. Client execution is going to cause the client to creep if not properly made.)
However have you considered just "fixing" your script so that it's a bit more compartmentalized. Surely the entirety of the function does not change every 10 ms? (On your site does it change from being a game of Pong to a looping weather radar graphic every 10 ms?)
compartimentalized javascript example (using jquery): Assumes you have two tags one with the class buttonA and one with the class buttonB. Clicking buttonA or buttonB changes internal values and then the script is executed.
var complicatedFunction = function(){
//private variables and methods
var a = 2, b = 3;
//public variables and methods
return {
exec: function(el){
//which button was pushed?
if($(el).is('.buttonA')){
a = 4;
b = 8;
} else {
a = 10;
b = 2;
}
alert('The result of a*b is ' +(a*b));
}
}
}();
$('.buttonA, .buttonB').click(function(){complicatedFunction.exec(this)});
Wish I could help more, if you post a code example maybe we can!