C 定义类

Question

`我需要有关 IPropertyChanged 的帮助，如何操作才能正常工作。

`C# 如何使用 IPropertyChanged 创建对象类？

我尝试在课堂上执行此操作，但它不起作用，我需要以某种方式更改它或添加一些方法。我正在尝试在 Employee 类中实现 INotifyPropertyChanged 接口，但无法使其正常工作。我需要确保正确通知财产变更。以下是我的实施细节：

员工类别： 此类代表具有姓名、职位、电话等属性的员工。 我已经实现了 INotifyPropertyChanged 来通知这些属性的更改。

    public string? Name { get; set; }
    public string? Position { get; set; }
    public string? Phone { get; set; }
    public string? Email { get; set; }
    public string? Room { get; set; }
    public string? MainWorkplace { get; set; }
    public string? Workplace { get; set; }

    public event PropertyChangedEventHandler? PropertyChanged;

Here is how it works, maybe i forgot to put some brackets. There are 3 classes, each represents some object, i need to apply inotifychanged to it EmployeeList Class: This class represents a collection of employees and provides methods to load from and save to a JSON file. It also includes methods to search employees and get distinct positions and workplaces.

public class EmployeeList : ObservableCollection<Employee>
{
    public static EmployeeList? LoadFromJson(FileInfo jsonFile)
    {
        if (!jsonFile.Exists)
            throw new FileNotFoundException("Súbor typu JSON neexistuje !", jsonFile.FullName);

        string jsonText = File.ReadAllText(jsonFile.FullName);
        EmployeeList? employeeList = JsonConvert.DeserializeObject<EmployeeList>(jsonText);

        return employeeList;
    }

    `public void SaveToJson(FileInfo jsonFile)
    {
        string jsonText = JsonConvert.SerializeObject(this, Formatting.Indented);
        File.WriteAllText(jsonFile.FullName, jsonText);
    }
    public IEnumerable<string?> GetPositions() => this.Select(employee => employee.Position).Distinct().OrderBy(p => p);
    public IEnumerable<string?> GetMainWorkplaces() => this.Select(employee => employee.MainWorkplace).Distinct().OrderBy(wp => wp);

    public SearchResult Search(string? name, string? position, string? mainWorkplace)
    {
        IEnumerable<Employee> emps = this.AsEnumerable();
        List<Employee> filteredEmps = new();

        foreach (var e in emps)
        {
            bool matchOfMW = true;
            bool matchOfP = true;
            bool matchOfN = true;

            if (!string.IsNullOrEmpty(mainWorkplace))
                matchOfMW = e.MainWorkplace?.IndexOf(mainWorkplace, StringComparison.OrdinalIgnoreCase) >= 0;

            if (!string.IsNullOrEmpty(position))
                matchOfP = e.Position?.IndexOf(position, StringComparison.OrdinalIgnoreCase) >= 0;

            if (!string.IsNullOrEmpty(name))
                matchOfN = e.Name?.IndexOf(name, StringComparison.OrdinalIgnoreCase) >= 0;

            if (matchOfMW && matchOfP && matchOfN)
                filteredEmps.Add(e);
        }

        Console.WriteLine($"Počet ľudí: {emps.Count()}");
        Console.WriteLine($"Z toho spĺňajúci: {filteredEmps.Count} \n");
        return new SearchResult(filteredEmps.ToArray());
    }
}`

`public class SearchResult
{
    public Employee[] Employees { get; }

    public SearchResult(Employee[] employees)
    {
        Employees = employees;
    }
    public void SaveToCsvFile(string filePath, string delimiter = "\t")
    {
        if (Employees == null)
            return;

        using (StreamWriter writer = new StreamWriter(filePath, false, Encoding.UTF8))
        {
            writer.Write("\uFEFF");
            writer.WriteLine($"Name{delimiter}Position{delimiter}Phone{delimiter}Email{delimiter}Room{delimiter}MainWorkplace{delimiter}Workplace");
            foreach (Employee e in Employees)
            {
                writer.WriteLine($"{e.Name}{delimiter}{e.Position}{delimiter}{e.Phone}{delimiter}{e.Email}" + $"{delimiter}{e.Room}{delimiter}{e.MainWorkplace}{delimiter}{e.Workplace}");
            }
        }

    }
    public int GetEmployeeCount()
    {
        return Employees.Length;
    }`

Here is how it works, maybe i forgot to put some brackets. There are 3 classes, each represents some object, i need to apply inotifychanged to it.

Answer 1

我会这样做

public class Employee : INotifyPropertyChanged
{
    private string _name = string.Empty;
    private string _position = string.Empty;
    private string? _mainWorkplace;
    private string _email = string.Empty;
    private string? _room;
    private string? _phone;
    private string? _workplace;

    public string Name { get => _name;
        set
        {
            if (_name != value)
            {
                _name = value;
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(Name));
            }
        }
    }
    public string Position { get => _position;
        set
        {
            if (_position != value)
            {
                _position = value;
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(Position));
            }
        }
    }
    public string? Phone { get => _phone;
        set
        {
            if (_phone != value)
            {
                _phone = value;
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(Phone));
            }
        }
    }

    public string Email { get => _email;
        set
        {
            if (_email != value)
            {
                _email = value;
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(Email));
            }
        }
    }

    public string? Room { get => _room;
        set
        {
            if (_room != value)
            {
                _room = value;
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(Room));
            }
        }
    }

    public string? MainWorkplace { get => _mainWorkplace;
        set
        {
            if (_mainWorkplace != value)
            {
                _mainWorkplace = value;
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(MainWorkplace));
            }
        }
    }

    public string? Workplace { get => _workplace; 
        set { 
            if (_workplace != value) { 
                _workplace = value;
                PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(Workplace));
            }
        }
        
    }






    public event PropertyChangedEventHandler? PropertyChanged;



}

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