C# 如何为集合设计多个筛选器
我的模型:C# 如何为集合设计多个筛选器,c#,wpf,algorithm,data-structures,data-binding,C#,Wpf,Algorithm,Data Structures,Data Binding,我的模型: public class Person { public string Name { get; set; } public bool Sex { get; set; } public string Country { get; set; } } 在我的WPF应用程序中,我想将一个列表绑定到DataGridControl,该视图还支持按性别和国家筛选 我当前的解决方案是创建一个List PersonList来存储所有数据,并创建另一个List PersonBi
public class Person
{
public string Name { get; set; }
public bool Sex { get; set; }
public string Country { get; set; }
}
在我的WPF应用程序中,我想将一个列表绑定到DataGridControl,该视图还支持按性别和国家筛选
我当前的解决方案是创建一个List PersonList来存储所有数据,并创建另一个List PersonBindingList来存储UI中应该显示的数据。当用户检查过滤器并单击“确定”时,使用Linq从PersonList查询并将结果分配给PersonBindingList以更新UI
但这应该保留两个列表。另外,我不希望每次用户更改过滤条件时都加载数据,因为数据量非常大,加载速度非常慢。还有其他解决办法吗?还有一件事,性和国家可以自由结合
如果您想在客户端过滤数据,请多谢(尤其是)您想要的:
public class ViewModel
{
// this is a property for filtering
public bool Sex
{
get { ... }
set
{
if (_sex != value)
{
_sex = value;
OnPropertyChanged();
PersonListView.Refresh();
}
}
}
// this is a property for filtering too
public string Country
{
// call PersonListView.Refresh in setter, as in Sex property setter
}
// this is a property for binding to DataGrid
public ICollectionView PersonListView
{
get
{
if (_personListView == null)
{
_personList = LoadPersons();
_personListView = new ListCollectionView(_personList)
{
Filter = p => ShouldViewPerson((Person)p);
}
}
return _personListView;
}
}
private bool ShouldViewPerson(Person p)
{
// implement filtering logic here;
// e.g.:
return p.Country.StartsWith(Country) && p.Sex == Sex;
}
private ListCollectionView _personListView;
private List<Person> _personList;
}
嗨,丹尼斯,谢谢你的回复。在您的代码中,性别和国家是ViewModel中的两个属性,如果我的过滤器支持多选,我应该在哪里调用Refresh方法?例如,我想展示美国和英国的男性。
// this is a filter item
public class CountryFilterItem : INotifyPropertyChanged
{
public string CountryName { ... }
public bool IsChecked { ... }
}
public class ViewModel
{
// this property is a replacement for "Country";
// bind it to some ItemsControl is the filter view
public IEnumerable<CountryFilterItem> Countries
{
get { return _countries; }
}
// fill filter somewhere;
// when filling, subscribe on `PropertyChanged` event of each item;
// when user will change IsChecked for item, you'll update filter:
//
// var country = new Country { CountryName = "Zimbabwe" };
// country.PropertyChanged += (sender, args) =>
// {
// if (propertyName == "IsChecked")
// {
// PersonListView.Refresh();
// }
// };
// _countries.Add(country);
private List<CountryFilterItem> _countries;
// filtering logic
private bool ShouldViewPerson(Person p)
{
// implement filtering logic here;
// e.g.:
return _countries.Any(_ => _.IsChecked && _.CountryName == p.Country) && p.Sex == Sex;
}
// other code here...
}