实现保存/加载功能的方法是什么？

Question

我正在尝试为Windows窗体应用程序实现加载/保存功能.

我有以下组件:

• 树视图
• 几个列表视图
• 几个文本框
• 一些对象(包含大型词典列表)

我想实现一种将所有这些保存到文件中的方法,并在以后恢复/加载它.

最好的方法是什么？

我认为XML序列化是可行的方法,但我不太确定如何或从哪里开始.或者它需要一个非常复杂的解决方案才能做到这一点？

Answer 1

理想情况下,您不应该持久保持UI状态; 你应该坚持表示你的数据的某个对象模型的状态.除了之外TreeView,使用数据绑定将对象模型绑定到UI是相当简单的.这可以是DataTable基于a 的方法,也可以是自定义类层次结构(我的偏好).

从UI分离数据后,保存数据非常简单.有很多例子XmlSerializer等等.

Answer 2

这是一个将对象和一些祖先绑定到UI的示例; 这里使用C#3.0纯粹是为了简洁 - 一切都适用于C#2.0.

这里的大多数代码都是设置表单和/或处理属性更改通知 - 重要的是,没有任何代码专门用于从对象模型更新UI,或者从UI更新对象模型.

另请注意,IDE可以为您执行大量数据绑定代码,只需将BindingSource放到表单上,并通过属性网格中的对话框将DataSource设置为类型.

请注意,提供属性更改通知(PropertyChanged)并不是必需的 - 但是,如果您实现此功能,大多数双向UI绑定将更好地工作.并不是说PostSharp有一些有趣的方法可以用最少的代码完成这项工作.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.IO;
using System.Windows.Forms;
using System.Xml.Serialization;
static class Program { // formatted for vertical space
    [STAThread]
    static void Main() {
        Application.EnableVisualStyles();

        Button load, save, newCust;
        BindingSource source = new BindingSource { DataSource = typeof(Customer) };
        XmlSerializer serializer = new XmlSerializer(typeof(Customer));
        using (Form form = new Form {
            DataBindings = {{"Text", source, "Name"}}, // show customer name as form title
            Controls = {
                new DataGridView { Dock = DockStyle.Fill, // grid of orders
                    DataSource = source, DataMember = "Orders"},
                new TextBox { Dock = DockStyle.Top, ReadOnly = true, // readonly order ref
                    DataBindings = {{"Text", source, "Orders.OrderRef"}}},
                new TextBox { Dock = DockStyle.Top, // editable customer name
                    DataBindings = {{"Text", source, "Name"}}},
                (save = new Button { Dock = DockStyle.Bottom, Text = "save" }),
                (load = new Button{ Dock = DockStyle.Bottom, Text = "load"}),
                (newCust = new Button{ Dock = DockStyle.Bottom, Text = "new"}),   
            }
        })
        {
            const string PATH = "customer.xml";
            form.Load += delegate {
                newCust.PerformClick(); // create new cust when loading form
                load.Enabled = File.Exists(PATH);
            };
            save.Click += delegate {
                using (var stream = File.Create(PATH)) {
                    serializer.Serialize(stream, source.DataSource);
                }
                load.Enabled = true;
            };
            load.Click += delegate {
                using (var stream = File.OpenRead(PATH)) {
                    source.DataSource = serializer.Deserialize(stream);
                }
            };
            newCust.Click += delegate {
                source.DataSource = new Customer();
            };
            Application.Run(form);
        } 
    }
}

[Serializable]
public sealed class Customer : NotifyBase {
    private int customerId;
    [DisplayName("Customer Number")]
    public int CustomerId {
        get { return customerId; }
        set { SetField(ref customerId, value, "CustomerId"); }
    }

    private string name;
    public string Name {
        get { return name; }
        set { SetField(ref name, value, "Name"); }
    }

    public List<Order> Orders { get; set; } // XmlSerializer demands setter

    public Customer() {
        Orders = new List<Order>();
    }
}

[Serializable]
public sealed class Order : NotifyBase {
    private int orderId;
    [DisplayName("Order Number")]
    public int OrderId  {
        get { return orderId; }
        set { SetField(ref orderId, value, "OrderId"); }
    }

    private string orderRef;
    [DisplayName("Reference")]
    public string OrderRef {
        get { return orderRef; }
        set { SetField(ref orderRef, value, "OrderRef"); }
    }

    private decimal orderValue, carriageValue;

    [DisplayName("Order Value")]
    public decimal OrderValue {
        get { return orderValue; }
        set {
            if (SetField(ref orderValue, value, "OrderValue")) {
                OnPropertyChanged("TotalValue");
            }
        }
    }

    [DisplayName("Carriage Value")]
    public decimal CarriageValue {
        get { return carriageValue; }
        set {
            if (SetField(ref carriageValue, value, "CarriageValue")) {
                OnPropertyChanged("TotalValue");
            }
        }
    }

    [DisplayName("Total Value")]
    public decimal TotalValue { get { return OrderValue + CarriageValue; } }
}

[Serializable]
public class NotifyBase { // purely for convenience
    [field: NonSerialized]
    public event PropertyChangedEventHandler PropertyChanged;

    protected bool SetField<T>(ref T field, T value, string propertyName) {
        if (!EqualityComparer<T>.Default.Equals(field, value)) {
            field = value;
            OnPropertyChanged(propertyName);
            return true;
        }
        return false;
    }
    protected virtual void OnPropertyChanged(string propertyName) {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
    }
}