删除数据网格 Wpf MVVM 中的重复行?

Question

当我从文本框添加新元素时，我试图删除数据网格中的重复元素。 也许，任何人都知道如何解决它？

public class ShellViewModel : Screen
{
private string _input = string.Empty;
public ObservableCollection<Person> people;
public ShellViewModel()
{
}
public string Input
{
get
{
return _input;
}
set
{
_input = value;
NotifyOfPropertyChange(() => Input);
}
}       
public ObservableCollection<Person> People
{
get
{
return people;
}
set
{
people = value;
NotifyOfPropertyChange(() => People);
}
}
Person person = new Person();
ObservableCollection<Person> persons = new ObservableCollection<Person>();
public void Write()
{
person.name = Input;
persons.Add(person);         
People = persons;                     
}
}

我在向 DataGrid 添加元素时没有任何问题，但我不知道如何删除重复的元素。 提前谢谢你。

Answer 1

在将Person添加到集合之前，您必须检查该是否已存在。

我还修复了您的代码的一些问题。由于People是一个ObservableCollection您可以直接向其添加项目，视图将注册集合中的更改并立即更新。在
将Person添加到集合时，还应创建一个新的实例，否则将覆盖现有实例。您当前使用的是单个Person。字段应始终private。

public class ShellViewModel : Screen
{ 
public void ShellViewModel()
{
this.Input = string.Empty;
this.People = new ObservableCollection<People>();      
}
private string _input = string.Empty;
public string Input
{
get => _input;
set
{
_input = value;
NotifyOfPropertyChange(() => Input);
}
}       
private ObservableCollection<Person> people;
public ObservableCollection<Person> People
{
get => people;
set
{
people = value;
NotifyOfPropertyChange(() => People);
}
}
public void Write()
{
if (string.IsNullOrWhiteSpace(this.input) 
|| this.People.Any(person => person.name.Equals(this.Input, StringComparison.OrdinalIgnoreCase))
{
return;
}
Person newPerson = new Person() {name = this.Input};
this.People.Add(newPerson);      
}
}

Answer 2

您可以避免添加重复记录

public void Write()
{
person.name = Input;
if (!persons.Contains(person))
persons.Add(person);
People = persons;
}