I need a load more button to control the repeater shown content.
Here is my steps in the back end after load more button was clicked:
Repeater bind data (Full data/All rows).
Keep the maximum items count (static) from the repeater.
Set total row to show (static) + 1 and initialize the value to select top N row as the limit.
Repeater bind data again (The amount to show only).
Check if repeater items count is less than maximum items count, if not then hide the load more button.
Suppose these steps can give me the expected output?
//Declaration
public static int max = 0;
public static int totalShow = 0;
//SetupControl()
if(!IsPostBack){
rptItems.ClassName = "Blog";
rptItems.Path = "/Shared/%"
rptItems.DataBind();
max = rptItems.Items.Count();
}
//This part is put under a new function
totalShow += 1;
rptItems.SelectTopN = totalShow;
rptItems.DataBind();
lbnLoadMore.Visible = rptItems.Items.Count() < max;
Besides, I'm confusing about the functions as shown below:
Both are from the class CMSRepeater, what's the different? Which one should I use in order to set the limits?
Using static members is definitely not a good approach. Their values would be shared by all users of the application. There are better ways of storing user-specific data:
session (server-side)
JS (client-side) and passing them to the server via query string or hidden field
Regarding TopN and SelectTopN, they do the same thing. It's probably because of backward compatibility.
From the algorithmical point of view, there's no need to bind data multiple times nor to make more than one round-trip to the database. You just need to initialize the datasource/repeater with correct values.
I'd recommend you reading the following articles to get some inspiration:
Turn a Kentico repeater web part into an infinite scroll / lazy loader by Laura Frese
Dynamic jQuery AJAX viewer by Jan Hermann
Related
Take a windowed virtual list with the capability of loading an arbitrary range of rows at any point in the list, such as in this following example.
The virtual list provides a callback that is called anytime the user scrolls to some rows that have not been fetched from the backend yet, and provides the start and stop indexes, so that, in an offset based pagination endpoint, I can fetch the required items without fetching any unnecessary data.
const loadMoreItems = (startIndex, stopIndex) => {
fetch(`/items?offset=${startIndex}&limit=${stopIndex - startIndex}`);
}
I'd like to replace my offset based pagination with a cursor based one, but I can't figure out how to reproduce the above logic with it.
The main issue is that I feel like I will need to download all the items before startIndex in order to receive the cursor needed to fetch the items between startIndex and stopIndex.
What's the correct way to approach this?
After some investigation I found what seems to be the way MongoDB approaches the problem:
https://docs.mongodb.com/manual/reference/method/cursor.skip/#mongodb-method-cursor.skip
Obviously he same approach can be adopted by any other backend implementation.
They provide a skip method that allows to skip an arbitrary amount of items after the provided cursor.
This means my sample endpoint would look like the following:
/items?cursor=${cursor}&skip=${skip}&limit=${stopIndex - startIndex}
I then need to figure out the cursor and the skip values.
The following code could work to find the closest available cursor, given I store them together with the items:
// Limit our search only to items before startIndex
const fragment = items.slice(0, startIndex);
// Find the closest cursor index
const cursorIndex = fragment.length - 1 - fragment.reverse().findIndex(item => item.cursor != null);
// Get the cursor
const cursor = items[cursorIndex];
And of course, I also have a way to know the skip value:
const skip = items.length - 1 - cursorIndex;
I has to display a list of books that containes more than 50 000 book.
I want to display paged list where for each page i invoke a method that gives me 20 books.
List< Books > Ebooks = Books.GetLibrary(index);
But using PagedList doesnt match with my want because it creates a subset of the collection of objects given and accesse to each subset with the index. And refering to the definition of its methode, i had to charge the hole list from the begining.
I also followed this article
var EBooks = from b in db.Books select b;
int pageSize = 20;
int pageNumber = (page ?? 1);
return View(Ebooks.ToPagedList(pageNumber, pageSize));
But doing so, i has to invoke (var Books = from b in db.Books select b; ) on each index
**EDIT****
I'm searching for indications to achieve this
List< Books > Ebooks = Books.GetLibrary(index);
and of course i has the number of all the books so i know the number of pages
So i'm searching for indication that leads me to achieve it: for each index, i invoke GetLibrary(index)
any suggestions ?
Have you tried something like:
var pagedBooks = Books.GetLibrary().Skip(pageNumber * pageSize).Take(pageSize);
This assumes a 0-based pageNumber.
If that doesn't work, can you add a new method to the Books class that gets a paged set directly from the data source?
Something like "Books.GetPage(pageNumber, pageSize);" that way you don't get the entire collection every time.
Other than that, you may have to find a way to cache the initial result of Books.GetLibrary() somewhere.
The following code is a script object on an XPage in it I loop through an array of all the forms in a database, looking for all the forms that contain the field "ACIncludeForm". My method works but it takes 2 - 3 seconds to compute which really slows the load of the XPage. My question is - is there a better method to accomplish this. I added code to check to see if the sessionScope variable is null and only execute if needed and the second time the page loads it does so in under a second. So my method really consumes a lot of processor time.
var forms:Array = database.getForms();
var rtn = new Array;
for (i=0 ; i<forms.length; ++i){
var thisForm:NotesForm = forms[i];
var a = thisForm.getFields().indexOf("ACIncludeForm");
if (a >= 0){
if (!thisForm.isSubForm()) {
if (thisForm.getAliases()[0] == ""){
rtn.push(thisForm.getName() + "|" + thisForm.getName() );
}else{
rtn.push(thisForm.getName() + "|" + thisForm.getAliases()[0] );
}
}
}
thisForm.recycle()
}
sessionScope.put("ssAllFormNames",rtn)
One approach would be to build an index of forms by yourself. For example, create an agent (LotusScript or Java) that gets all forms and for each form, create a document with for example a field "form" containing the form name and and a field "fields" containing all field names (beware of 32K limit).
Then create a view that displays all these documents and contains the value of the "fields" field in the first column so that each value of this field creates one line in this view.
Having such a view, you can simply make a #DbLookup from your XPage.
If your forms are changed, you only need to re-run the agent to re-build your index. The #DbLookup should be pretty fast.
Place the form list in a static field of a Java class. It will stay there for a long time (maybe until http boot). In my experience applicationScope values dissappear in 15 minutes.
I have a notes form with a series of fields such as city_1, city_2, city_3 etc.
I have an XPage and on that XPage I have a repeat.
The repeat is based on an array with ten values 1 - 10
var repArray = new Array() ;
for (var i=1;i<=10;i++) {
repArray.push(i) ;
}
return(repArray) ;
Within the repeat I have a custom control which is used to surface the fields city_1 through city_10
The repeat has a custom property docdatasource which is passed in
It also has a string custom property called cityFieldName which is computed using the repeat
collection name so that in the first repeat row it is city_1 and in the second it is city_2 etc..
The editable text field on the custom control is bound using the EL formula
compositeData.docdatasource[compositeData.cityFieldName]
This works fine but each time I add new fields I have to remember to create a new custom property and then a reference to it on the parent page.
I would like to be able to simply compute the data binding such as
compositeData.docdatasource['city_' + indexvar]
where indexvar is a variable representing the current row number.
Is this possible ? I have read that you cannot use '+' in Expression Language.
First: you wouldn't need an array for a counter. Just 10 would do (the number) - repeats 10 times too. But you could build an array of arrays:
var repArray = [];
for (var i=1;i<=10;i++) {
repArray.push(["city","street","zip","country","planet"]) ;
}
return repArray;
then you should be able to use
#{datasource.indexvar[0]}
to bind city,
#{datasource.indexvar[1]}
to bind street. etc.
Carries a little the danger of messing with the sequence of the array, if that's a concern you would need to dig deeper in using an Object here.
compute to javascript and use something like
var viewnam = "#{" + (compositeData.searchVar )+ "}"
return viewnam
make sure this is computed on page load in the custom control
I was never able to do the addition within EL but I have been very successful with simply computing the field names outside the custom control and then passing those values into the custom control.
I can send you some working code if you wish from a presentation I gave.
I have a SharePoint list column of type 'Single line of text'. Out of the box SharePoint only provides the ability to display a 'Count' total for this column type. I would like to be able to perform a custom aggregation on the data (specifically to sum numeric data held as text to overcome this deficiency).
I have found examples for doing something similar for calculated columns using XSLT and Javascript but I believe that both of these approaches fail where the data is paginated (only aggregating the subset of the list content displayed on screen).
I want to retain the functionality of the ListViewWebPart (rendering, sorting, filtering, view definition, action menus etc.) but add this functionality. How can I do this?
The only things you can do with totals are:
Average; Count; Max; Min; Sum; Standard Deviation; Variance
Not sure how to calculate anything else.
I've not had a chance to fully test it but this is the best I could come up with:
Create a WebPart which contains two controls:
A ViewToolBar with the context of the list/view to be displayed
A Literal containing the rendered HTML of the view to be displayed
This will then render as the original list/view.
On rendering the WebPart, get the items from the view, specifying the RowLimit as the maximum value so that all items in are retrieved (not just the first page).
Iterate over the items, calculating the total in a suitable data type to retain precision.
Render the total as a hidden value in the HTML and overwrite the rendered Count total with Javascript such as by the method described here.
A rough sketch of the code:
public sealed class TextAggregatingWebPart : WebPart {
protected override void CreateChildControls() {
base.CreateChildControls();
var web = SPContext.Current.Web;
var list = web.Lists[SourceList];
var view = list.Views[ViewOfSourceList];
var toolbar = new ViewToolBar();
var context = SPContext.GetContext(
Context, view.ID, list.ID, SPContext.Current.Web);
toolbar.RenderContext = context;
Controls.Add(toolbar);
var viewHtml = new Literal {Text = view.RenderAsHtml()};
Controls.Add(viewHtml);
}
protected override void Render(HtmlTextWriter writer) {
EnsureChildControls();
base.Render(writer);
var web = SPContext.Current.Web;
var list = web.Lists[SourceList];
var view = list.Views[ViewOfSourceList];
var items = list.GetItems(new SPQuery(view) {RowLimit = uint.MaxValue});
foreach (SPItem item in items) {
// Calculate total
}
// Render total and Javascript to replace Count
}
}
Note that this doesn't solve the problem with the Modify View screen only showing Count as a total for text columns. Also there is a possibility that changes to the list between the initial rendering by the view and the retrieval of the items for aggregation could produce discrepancies between the total and the displayed items.