Collections
Structr.Collections package is intended to help organize search results collections into pagination-friendly arrays, which provide all needed data to display page control buttons in UI. Instance of package main class - PageList
- contains data about page number, page size, first and last pages of whole selection, etc.
Installation
Collections package is available on NuGet.
Usage
Let's imagine we have some set of goods gotten from database using search criteria "fruits":
But for some reason we could show only 3 items from search results per page. So, user will get totally 5 pages and currently will see one of them. Let it be the second one. Than after using all skips and takes in our SQL-query we'll get something like this:
Before sending this result to presentation level, it will be nice to send some pagination info along with fruits
-list to provide data you need for user control generation purpose. These are: buttons with page numbers, arrows, total count info. At this moment PagedList
comes to our help:
totalItems
parameter (which is 13) usually comes from first SQL COUNT(*)
-like query intended to get total count of elements in search before applying SKIP
and TAKE
operators. The second and third parameters here are: pageNumber
and pageSize
respectively. Based on such result
you can successfully create user interface or provide info about search results to you API-client.
Properties
Property name | Property type | Description |
---|---|---|
TotalItems |
| Gets declared total count of items in superset collection. |
PageNumber |
| Gets current page number. |
PageSize |
| Gets page size. |
TotalPages |
| Gets total count of pages. |
HasPreviousPage |
| Determines if there is a page before current. |
HasNextPage |
| Determines if there is a page after current. |
IsFirstPage |
| Determines whether current page is the first one. |
IsLastPage |
| Determines whether current page is the last one. |
FirstItemOnPage |
| Gets number of first item on page. |
LastItemOnPage |
| Gets number of last item on page. |
Count |
| Gets count of items on page. |
Static methods
Method name | Return type | Description |
---|---|---|
Empty |
| Creates an empty paged list. |
Extensions
To easily get a paged list from the original list use extension methods:
It is very common to convert an existing paged list of items of one type (Entities for example) into an paged list of items of another type (DTO for example).
For such conversion it is best to use AutoMapper extensions.
Use SerializablePagedList
class with ToSerializablePagedList()
and ToPagedList()
methods if you need serialize and deserialize a paged list (to JSON for example):
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