oqtane.framework/Oqtane.Client/Modules/Controls/Pager.razor

@namespace Oqtane.Modules.Controls
@inherits ModuleBase
@typeparam TableItem

<p>
    @if(Format == "Table")
    {
    <table class="@Class">
        <thead>
            <tr>@Header</tr>
        </thead>
        <tbody>
            @foreach (var item in ItemList)
            {
                <tr>@Row(item)</tr>
                @if (Detail != null)
                {
                    <tr>@Detail(item)</tr>
                }
            }
        </tbody>
    </table>
    }
    @if(Format == "Grid")
    {
    <div class="@Class">
        <div class="row">@Header</div>
        @foreach (var item in ItemList)
        {
            <div class="row">@Row(item)</div>
            @if (Detail != null)
            {
                <div class="row">@Detail(item)</div>
            }
        }
    </div>
    }
    <div class="mx-auto text-center">
        @if (_page > _maxPages)
        {
            <button class="btn btn-secondary" @onclick=@(async () => SetPagerSize("back"))><span class="oi oi-media-skip-backward" title="back" aria-hidden="true"></span></button>
        }
        @if (_endPage > 1)
        {
            <button class="btn btn-secondary" @onclick=@(async () => NavigateToPage("previous"))><span class="oi oi-chevron-left" title="previous" aria-hidden="true"></span></button>            
            @for (int i = _startPage; i <= _endPage; i++)
            {
                var pager = i;
                <button class="btn @((pager == _page) ? "btn-primary" : "btn-link")" @onclick=@(async () => UpdateList(pager))>
                    @pager
                </button>
            }
            <button class="btn btn-secondary" @onclick=@(async () => NavigateToPage("next"))><span class="oi oi-chevron-right" title="next" aria-hidden="true"></span></button>
        }
        @if (_endPage < _pages)
        {
            <button class="btn btn-secondary" @onclick=@(async () => SetPagerSize("forward"))><span class="oi oi-media-skip-forward" title="forward" aria-hidden="true"></span></button>
        }
        @if (_endPage > 1)
        {
            <span class="btn btn-link disabled">Page @_page of @_pages</span>
        }
    </div>
</p>

@code {
    private int _pages = 0;
    private int _page = 1;
    private int _maxItems;
    private int _maxPages;
    private int _startPage;
    private int _endPage;

    [Parameter]
    public string Format { get; set; }

    [Parameter]
    public RenderFragment Header { get; set; }

    [Parameter]
    public RenderFragment<TableItem> Row { get; set; }

    [Parameter]
    public RenderFragment<TableItem> Detail { get; set; }

    [Parameter]
    public IEnumerable<TableItem> Items { get; set; }

    [Parameter]
    public string PageSize { get; set; }

    [Parameter]
    public string DisplayPages { get; set; }

    [Parameter]
    public string Class { get; set; }

    private IEnumerable<TableItem> ItemList { get; set; }

    protected override void OnParametersSet()
    {
        if (string.IsNullOrEmpty(Format))
        {
            Format = "Table";
        }
        
        if (string.IsNullOrEmpty(Class))
        {
            if (Format == "Table")
            {
                Class = "table table-borderless";
            }
            else
            {
                Class = "container";
            }
        }
        
        if (string.IsNullOrEmpty(PageSize))
        {
            _maxItems = 10;
        }
        else
        {
            _maxItems = int.Parse(PageSize);
        }
        
        if (string.IsNullOrEmpty(DisplayPages))
        {
            _maxPages = 5;
        }
        else
        {
            _maxPages = int.Parse(DisplayPages);
        }

        if (Items != null)
        {
            ItemList = Items.Skip((_page - 1) * _maxItems).Take(_maxItems);
            _pages = (int)Math.Ceiling(Items.Count() / (decimal)_maxItems);
        }

        SetPagerSize("forward");
    }

    public void UpdateList(int currentPage)
    {
        ItemList = Items.Skip((currentPage - 1) * _maxItems).Take(_maxItems);
        _page = currentPage;
        
        StateHasChanged();
    }

    public void SetPagerSize(string direction)
    {
        if (direction == "forward")
        {
            if (_endPage + 1 < _pages)
            {
                _startPage = _endPage + 1;
            }
            else
            {
                _startPage = 1;
            }

            if (_endPage + _maxPages < _pages)
            {
                _endPage = _startPage + _maxPages - 1;
            }
            else
            {
                _endPage = _pages;
            }
            
            StateHasChanged();
        }
        else if (direction == "back")
        {
            _endPage = _startPage - 1;
            _startPage = _startPage - _maxPages;
        }
    }

    public void NavigateToPage(string direction)
    {
        if (direction == "next")
        {
            if (_page < _pages)
            {
                if (_page == _endPage)
                {
                    SetPagerSize("forward");
                }
                _page += 1;
            }
        }
        else if (direction == "previous")
        {
            if (_page > 1)
            {
                if (_page == _startPage)
                {
                    SetPagerSize("back");
                }
                _page -= 1;
            }
        }
        
        UpdateList(_page);
    }
}