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c# - 保存并加载我的 listview/observablecolletion 到 txt

问题描述

当我打开和关闭应用程序时，我需要保存并加载一个 listview / observablecollection。

我在这里和其他地方搜索过，并尝试了一些东西，但似乎没有任何效果。

我已经粘贴了我发现的代码，我认为它可以解决问题。也许它确实有一些变化。

//This one is for adding items, and it works fine.

try
                {

                    Tanknings.Add(new Tankning { Date = Dato.Date.ToString("dd-MM-yyyy"),
                        KmTaeller = KmTaeller.Text,
                        LiterTanket = Math.Round(Convert.ToDouble(LiterTanket.Text), 2).ToString(),
                        Pris = Math.Round(Convert.ToDouble(Pris.Text), 2).ToString(),
                        KmKoert = (Convert.ToInt32(KmTaeller.Text) - Convert.ToInt32(AktuelKmTaeller.Text)).ToString(),
                        PrisPrLiter = Math.Round((Convert.ToDouble(Pris.Text) / Convert.ToDouble(LiterTanket.Text)), 2).ToString(),
                        KmPrLiter = Math.Round(((Convert.ToDouble(KmTaeller.Text) - (Convert.ToDouble(AktuelKmTaeller.Text))) / Convert.ToDouble(LiterTanket.Text)), 2).ToString() });
            }
                catch
                {
                }

//This i what i tried to save and load the items.

private async void saveTankninger()
        {
            XmlSerializer xs = new XmlSerializer(typeof(ObservableCollection<Tankning>));

            using (StreamWriter wr = new StreamWriter("Files/Tankninger.xml"))
            {
                xs.Serialize(wr, Tanknings);
            }

            /* Firstly we will use StorageFolder class from the Windows.Storage namespace
            to get path to the LocalFolder for our application: */
            StorageFolder storageFolder = ApplicationData.Current.LocalFolder;

            /* Then we need to have reference to the file where we can store notes:
            Note that if file exists we do not want to create another one: */
            StorageFile notesFile = await storageFolder.CreateFileAsync("Tankninger.txt", CreationCollisionOption.OpenIfExists);

            // Now we want to serialize list with the notes to save it in the JSON format ine the file:
            var serializedNotesList = JsonConvert.SerializeObject(Tanknings);

            // Last step is to write serialized list with notes to the text file:
            await FileIO.WriteTextAsync(notesFile, serializedNotesList);
        }

        private async void loadTankninger()
        {
            /* Firstly we will use StorageFolder class from the Windows.Storage namespace
            to get path to the LocalFolder for our application: */
            StorageFolder storageFolder = ApplicationData.Current.LocalFolder;

            /* Then we need to have reference to the file where we can store notes:
            Note that if file exists we do not want to create another one: */
            StorageFile notesFile = await storageFolder.CreateFileAsync("Tankninger.txt", CreationCollisionOption.OpenIfExists);

            // Read serialized notes list from the file:
            string serializedNotesList = await FileIO.ReadTextAsync(notesFile);

            // Deserialize JSON list to the ObservableCollection:
            if (serializedNotesList != null)
            {
                Tanknings = JsonConvert.DeserializeObject<ObservableCollection<Tankning>>(serializedNotesList);
                tankningTable.ItemsSource = Tanknings;
            }
        }

标签： c#

解决方案

假设您正在使用 newtonsoft JSON 库并已填充 List

序列化：

using Newtonsoft.Json;

List<Class_name> aList = getListFromSomehwere();
string json = JsonConvert.SerializeObject(aList);
// Do whatever you want with string, e.g. save to file

反序列化：

using Newtonsoft.Json;
string json = ReadFile(); // Your function to read all text from file

List<Class_name> aList = (JsonConvert.DeserializeObject<IEnumerable<Class_name>>(json)).ToList();
// Do whatever you want with this list

要在关闭时保存 - 只需将事件添加到您的应用程序关闭事件、序列化列表并将其保存到文件中。

要在加载时打开 - 添加 window_loaded 事件（或显示的表单或您喜欢的任何内容），读取所有文件，反序列化 json。有很多方法可以解决这个问题，您可以决定要做什么。

编辑：JSON.NET DeserializeObject 到对象列表可能会有所帮助

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