ASP NET Core --- HTTP 翻页、过滤、排序

参照 草根专栏- ASP.NET Core + Ng6 实战：https://v.qq.com/x/page/v07647j3zkq.html

翻页, 过滤, 排序等 – 如何传递参数?

Query String

• http://localhost:5000/api/country?pageIndex=12&pageSize=10&orderBy=id

使用抽象父类 QueryParameters, 包含常见参数:

• PageIndex, PageSize, OrderBy …

 

一、翻页：

 1、在Core.Entity 中添加 QueryParameters.cs 类

namespace BlogDemo.Core.Entities
{
    public abstract class QueryParameters : INotifyPropertyChanged
    {
        private const int DefaultPageSize = 10;
        private const int DefaultMaxPageSize = 100;

        private int _pageIndex;
        public int PageIndex
        {
            get => _pageIndex;
            set => _pageIndex = value >= 0 ? value : 0;
        }

        private int _pageSize = DefaultPageSize;
        public virtual int PageSize
        {
            get => _pageSize;
            set => SetField(ref _pageSize, value);
        }

        private string _orderBy;
        public string OrderBy
        {
            get => _orderBy;
            set => _orderBy = value ?? nameof(IEntity.Id);
        }

        private int _maxPageSize = DefaultMaxPageSize;
        protected internal virtual int MaxPageSize
        {
            get => _maxPageSize;
            set => SetField(ref _maxPageSize, value);
        }

        public string Fields { get; set; }

        public event PropertyChangedEventHandler PropertyChanged;

        protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

        protected bool SetField<T>(ref T field, T value, [CallerMemberName] string propertyName = null)
        {
            if (EqualityComparer<T>.Default.Equals(field, value))
            {
                return false;
            }
            field = value;
            OnPropertyChanged(propertyName);
            if (propertyName == nameof(PageSize) || propertyName == nameof(MaxPageSize))
            {
                SetPageSize();
            }
            return true;
        }

        private void SetPageSize()
        {
            if (_maxPageSize <= 0)
            {
                _maxPageSize = DefaultMaxPageSize;
            }
            if (_pageSize <= 0)
            {
                _pageSize = DefaultPageSize;
            }
            _pageSize = _pageSize > _maxPageSize ? _maxPageSize : _pageSize;
        }
    }
}

View Code