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Update pagination posts

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This commit is contained in:
Neil Brommer 2024-06-05 11:42:31 -07:00
parent f7f8399b63
commit 25f32cefbb
2 changed files with 107 additions and 77 deletions
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64
src/posts/CsPaginationTools.md
View file

@ -32,21 +32,11 @@ namespace ASIS.Shared;
[DataContract(IsReference = true)]
public class PaginationOptions
{
/// <summary>
/// This constructor exists so that MVC can instantiate the object before mapping is contents
/// </summary>
public PaginationOptions() { }
public PaginationOptions(int pageNumber, int? resultsPerPage)
{
this.PageNumber = pageNumber;
this.ResultsPerPage = resultsPerPage;
}
private int? _resultsPerPage;
private int _pageNumber;
/// <summary>The number of results per page</summary>
/// <remarks><c>null</c> for unlimited</remarks>
[DataMember]
public int? ResultsPerPage
{
@ -61,9 +51,7 @@ public class PaginationOptions
}
}
/// <summary>
/// The page number to get
/// </summary>
/// <summary>The page number to get</summary>
/// <remarks>One indexed</remarks>
[DataMember]
public int PageNumber
@ -78,8 +66,39 @@ public class PaginationOptions
this._pageNumber = value;
}
}
/// <summary>
/// This constructor exists so that MVC can instantiate the object before mapping is contents
/// </summary>
public PaginationOptions() { }
public PaginationOptions(int pageNumber, int? resultsPerPage)
{
this.PageNumber = pageNumber;
this.ResultsPerPage = resultsPerPage;
}
}
/// <summary>
/// This exists because <see cref="TagHelper"/>s can't be generic, so passing them an actual
/// <see cref="PaginatedResults{T}"/> wouldn't work
/// </summary>
public interface IPaginatedResults
{
public int PageNumber { get; }
public int LastPageNumber { get; }
public int? ResultsPerPage { get; }
public int CurrentPageResultsCount { get; }
public int TotalResultsCount { get; }
public int FirstResultNumber { get; }
public int LastResultNumber { get; }
public bool IsFirstPage { get; }
public bool IsLastPage { get; }
public int PreviousPageNumber { get; }
public int NextPageNumber { get; }
}
/// <summary>
/// An extension of <see cref="PaginationOptions"/> that contains the results from a query and uses
/// them to calculate additional pagination info
@ -89,7 +108,7 @@ public class PaginationOptions
/// </typeparam>
/// <typeparam name="U">The data type of the results</typeparam>
[DataContract(IsReference = true)]
public class PaginatedResults<T> : PaginationOptions where T : class
public class PaginatedResults<T> : PaginationOptions, IPaginatedResults where T : class
{
[JsonConstructor]
public PaginatedResults(int pageNumber, int? resultsPerPage, IEnumerable<T> results,
@ -118,21 +137,21 @@ public class PaginatedResults<T> : PaginationOptions where T : class
/// The number of results on the current page
/// </summary>
[DataMember]
public int? CurrentPageResultsCount { get => this.Results.Count(); }
public int CurrentPageResultsCount { get => this.Results.Count(); }
/// <summary>
/// The number of the first result on the current page. This is calculated using
/// <see cref="ResultsPerPage"/>, <see cref="PageNumber"/>, and <see cref="TotalResults"/>.
/// </summary>
[DataMember]
public int? FirstResultNumber
public int FirstResultNumber
{
get
{
if (this.ResultsPerPage is null)
return 1;
return (this.ResultsPerPage * (this.PageNumber - 1)) + 1;
return ((int)this.ResultsPerPage * (this.PageNumber - 1)) + 1;
}
}
@ -141,14 +160,14 @@ public class PaginatedResults<T> : PaginationOptions where T : class
/// <see cref="ResultsPerPage"/>, <see cref="PageNumber"/>, and <see cref="TotalResults"/>.
/// </summary>
[DataMember]
public int? LastResultNumber
public int LastResultNumber
{
get
{
if (this.ResultsPerPage is null)
return this.Results.Count();
return (this.ResultsPerPage * (this.PageNumber - 1)) + this.CurrentPageResultsCount;
return ((int)this.ResultsPerPage * (this.PageNumber - 1)) + this.CurrentPageResultsCount;
}
}
@ -157,15 +176,14 @@ public class PaginatedResults<T> : PaginationOptions where T : class
/// <see cref="TotalResultsCount"/>
/// </summary>
[DataMember]
public int? LastPageNumber
public int LastPageNumber
{
get
{
if (this.ResultsPerPage is null)
return 1;
return (int)Math.Ceiling(this.TotalResultsCount
/ (double)this.ResultsPerPage);
return (int)Math.Ceiling(this.TotalResultsCount / (double)this.ResultsPerPage);
}
}

112
src/posts/PaginationTagHelpers.md
View file

@ -27,28 +27,36 @@ The query parameter given as `page-number-key` will be changed or added to each
The `pager-details` tag helper:
```csharp
using ASIS.SecretsManagement.Shared;
using ASIS.Shared;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.TagHelpers;
using Microsoft.AspNetCore.Razor.TagHelpers;
using System.Text.Encodings.Web;
namespace ASIS.Shared.TagHelpers;
/// <summary>
/// Displays details about pagination in the form "Showing results x - y of z" on the left and
/// "Page x of y" on the right
/// </summary>
public class PagerDetailsTagHelper : TagHelper
public class PaginationDetailsTagHelper : TagHelper
{
public PaginatedResults<object> Results { get; set; }
public required IPaginatedResults Results { get; set; }
/// <summary>
/// The name for the item to be displayed, e.g. <c>results</c>. This will be used in the format
/// "Showing <c>results</c> 1-10 of 100".
/// </summary>
public string ResultName { get; set; } = "results";
public override void Process(TagHelperContext context, TagHelperOutput output)
{
output.TagName = "div";
output.TagMode = TagMode.StartTagAndEndTag;
output.AddClass("paginationDetails", HtmlEncoder.Default);
output.AddClass("pagination-details", HtmlEncoder.Default);
TagBuilder resultsNumDetails = new("span");
resultsNumDetails.InnerHtml.Append("Showing results "
resultsNumDetails.InnerHtml.Append($"Showing {this.ResultName} "
+ $"{this.Results.FirstResultNumber} - {this.Results.LastResultNumber} "
+ $"of {this.Results.TotalResultsCount}");
output.Content.AppendHtml(resultsNumDetails);
@ -64,7 +72,6 @@ public class PagerDetailsTagHelper : TagHelper
And the `pager` tag helper:
```csharp
using ASIS.SecretsManagement.Shared;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using Microsoft.AspNetCore.Razor.TagHelpers;
@ -72,6 +79,8 @@ using Microsoft.AspNetCore.WebUtilities;
using Microsoft.Extensions.Primitives;
using System.Collections.Immutable;
namespace ASIS.Shared.TagHelpers;
/// <summary>
/// Creates a list of links to pages for the current list of data. This will replace the page number
/// parameter in the query string using the <see cref="PageNumberKey"/>.
@ -79,56 +88,64 @@ using System.Collections.Immutable;
/// <remarks>
/// Page 1 is assumed to be the default and the page number parameter will be excluded
/// </remarks>
public class PagerTagHelper : TagHelper
public class PaginationTagHelper : TagHelper
{
public required IPaginatedResults Results { get; set; }
/// <summary>The name of the page number parameter in the query string</summary>
public string PageNumberKey { get; set; }
public PaginatedResults<object> Results { get; set; }
public required string PageNumberKey { get; set; }
[ViewContext, HtmlAttributeNotBound]
public ViewContext ViewContext { get; set; }
public required ViewContext ViewContext { get; set; }
private string CurrentPagePath { get => this.ViewContext.HttpContext.Request.Path; }
private string CurrentPagePath
{
get => this.ViewContext.HttpContext.Request.PathBase
+ this.ViewContext.HttpContext.Request.Path;
}
private ImmutableDictionary<string, StringValues> QueryStringValues { get; set; }
= ImmutableDictionary.Create<string, StringValues>();
public override void Process(TagHelperContext context, TagHelperOutput output)
{
output.TagName = "nav";
output.TagMode = TagMode.StartTagAndEndTag;
output.AddClass("wsu-pagination", HtmlEncoder.Default);
output.Attributes.Add("aria-label", "pagination");
var paginationList = new TagBuilder("ul");
paginationList.AddCssClass("pagination");
TagBuilder paginationList = new("ul");
paginationList.AddCssClass("wsu-pagination__menu");
this.QueryStringValues = QueryHelpers
.ParseQuery(this.ViewContext.HttpContext.Request.QueryString.Value)
.ToImmutableDictionary()
.Remove(this.PageNumberKey);
paginationList.InnerHtml.AppendHtml(this.CreatePreviousPageItem());
foreach (int i in Enumerable.Range(1, this.Results.LastPageNumber))
{
paginationList.InnerHtml.AppendHtml(this.CreatePageItem(i, i.ToString()));
}
paginationList.InnerHtml.AppendHtml(this.CreateNextPageItem());
output.Content.AppendHtml(this.CreatePreviousPageItem());
output.Content.AppendHtml(paginationList);
output.Content.AppendHtml(this.CreateNextPageItem());
}
private TagBuilder CreatePageItem(int pageNumber, string linkText)
{
var listItem = new TagBuilder("li");
var link = new TagBuilder("a");
TagBuilder listItem = new("li");
listItem.AddCssClass("wsu-pagination__menu-page");
TagBuilder link = new("a");
link.Attributes.Add("aria-label", $"Goto Page {pageNumber}");
if (pageNumber == this.Results.PageNumber)
link.AddCssClass("currentPage");
link.Attributes.Add("aria-current", "true");
link.InnerHtml.AppendHtml(linkText);
// Leave off the number for page 1
var queryStringWithPageNumber = pageNumber == 1
ImmutableDictionary<string, StringValues> queryStringWithPageNumber = pageNumber == 1
? this.QueryStringValues
: this.QueryStringValues.Add(this.PageNumberKey, pageNumber.ToString());
@ -141,14 +158,18 @@ public class PagerTagHelper : TagHelper
private TagBuilder CreatePreviousPageItem()
{
var listItem = new TagBuilder("li");
var link = new TagBuilder("a");
TagBuilder link = new("a");
link.AddCssClass("wsu-pagination__previous");
link.AddCssClass("wsu-button");
link.AddCssClass("wsu-button--style-outline");
link.Attributes.Add("aria-label", "Goto Previous Page");
if (this.Results.IsFirstPage)
link.AddCssClass("disabled");
link.Attributes.Add("disabled", "disabled");
// Leave off the number for page 1
var queryStringWithPageNumber = this.Results.PreviousPageNumber == 1
ImmutableDictionary<string, StringValues> queryStringWithPageNumber =
this.Results.PreviousPageNumber == 1
? this.QueryStringValues
: this.QueryStringValues
.Add(this.PageNumberKey, this.Results.PreviousPageNumber.ToString());
@ -156,44 +177,35 @@ public class PagerTagHelper : TagHelper
link.Attributes.Add("href", QueryHelpers.AddQueryString(
this.CurrentPagePath, queryStringWithPageNumber));
link.InnerHtml.AppendHtml("«");
link.InnerHtml.AppendHtml("Previous");
listItem.InnerHtml.AppendHtml(link);
return listItem;
return link;
}
private TagBuilder CreateNextPageItem()
{
var listItem = new TagBuilder("li");
var link = new TagBuilder("a");
TagBuilder link = new("a");
link.AddCssClass("wsu-pagination__next");
link.AddCssClass("wsu-button");
link.AddCssClass("wsu-button--style-outline");
link.Attributes.Add("aria-label", "Goto Next Page");
if (this.Results.IsLastPage)
link.AddCssClass("disabled");
link.Attributes.Add("disabled", "disabled");
// Leave off the number for page 1
var queryStringWithPageNumber = this.Results.NextPageNumber == 1
ImmutableDictionary<string, StringValues> queryStringWithPageNumber =
this.Results.NextPageNumber == 1
? this.QueryStringValues
: this.QueryStringValues.Add(this.PageNumberKey, this.Results.NextPageNumber.ToString());
: this.QueryStringValues
.Add(this.PageNumberKey, this.Results.NextPageNumber.ToString());
link.Attributes.Add("href", QueryHelpers.AddQueryString(
this.CurrentPagePath, queryStringWithPageNumber));
link.Attributes.Add("href", QueryHelpers
.AddQueryString(this.CurrentPagePath, queryStringWithPageNumber));
link.InnerHtml.AppendHtml("»");
link.InnerHtml.AppendHtml("Next");
listItem.InnerHtml.AppendHtml(link);
return listItem;
}
}
public static class PaginatedResultsExtensions
{
/// <summary>Razor doesn't like casting, so use this instead</summary>
public static PaginatedResults<object> ToObjectPaginatedResults<T>(
this PaginatedResults<T> paginatedResults) where T : class
{
return new PaginatedResults<object>(paginatedResults.PageNumber,
paginatedResults.ResultsPerPage, paginatedResults.Results,
paginatedResults.TotalResultsCount);
return link;
}
}
```