如何从 DataGrid 在数据库中添加新行或删除行

Question

所以我在WPF 中有这个学校项目，我必须将DataGrid 绑定到SQLite DataBase。在XAML 我还有3 个buttons：Load（加载表格）、Update 和Cancel（取消所有更改并直接从ObservableCollection 重新加载DataGrid。 我在这里有XAML 行：

<DataGrid x:Name="dataGrid" AutoGenerateColumns="True" Canvas.Left="10" Canvas.Top="10" AlternatingRowBackground="LightGreen" Height="245" Width="500" ItemsSource="{Binding Userss.UserCol, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" DataContext="{Binding RelativeSource={RelativeSource Self}}"/>

我有一个UserssClass，在那里我创建了我的ObservableCollection，用于存储来自我的SQLitedatabase 的数据。

public class Userss : INotifyPropertyChanged
{
    public static SQLiteConnection m_dd = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;");

    private static ObservableCollection<Userss> userCol = new ObservableCollection<Userss>();

    public ObservableCollection<Userss> UserCol
    {
        get { return userCol; }
        set
        {
            userCol = value;
            RaisePropertyChanged();
        }
    }

    public int Id { get; set; }
    private string _name;
    public string Name
    {
        get { return _name; }
        set
        {
            _name = value;
            RaisePropertyChanged();
        }
    }

    private Sex _sex;
    public Sex Sex
    {
        get { return _sex; }
        set
        {
            _sex = value;
            RaisePropertyChanged();
        }
    }

    private Stations _station;
    public Stations Station
    {
        get { return _station; }
        set
        {
            _station = value;
            RaisePropertyChanged();
        }
    }

    private Jobs _job;
    public Jobs Job
    {
        get { return _job; }
        set
        {
            _job = value;
            RaisePropertyChanged();
        }
    }

    private DateTime _date;
    public DateTime Date
    {
        get { return _date; }
        set
        {
            _date = value;
            RaisePropertyChanged();
        }
    }

    public static ObservableCollection<Userss> GetValues()
    {
        m_dd.Open();
        string sql = "select id,name,sex,station,job,date from user";
        userCol.Clear();
        SQLiteCommand cmd = new SQLiteCommand(sql, m_dd);
        SQLiteDataReader reader = cmd.ExecuteReader();
        while (reader.Read())
        {
            string sex1 = reader["sex"].ToString();
            string station1 = reader["station"].ToString();
            string job1 = reader["job"].ToString();
            string data1 = reader["date"].ToString();
            userCol.Add(new Userss()
            {
                Id = Convert.ToInt32(reader["id"]),
                Name = reader["name"].ToString(),
                Sex = (Sex)Enum.Parse(typeof(Sex), sex1),
                Station = (Stations)Enum.Parse(typeof(Stations), station1),
                Job = (Jobs)Enum.Parse(typeof(Jobs), job1),
                Date = Convert.ToDateTime(data1)
            });
        }
        m_dd.Close();
        return userCol;
    }

    public event PropertyChangedEventHandler PropertyChanged;

    private void RaisePropertyChanged([CallerMemberName] string caller = "")
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(caller));
        }
    }
}

public enum Sex
{
    Male,
    Female
}
public enum Jobs
{
    Programmer,
    Designer,
    Manager,
    CTO,
    CEO,
}
public enum Stations
{
    Desktop,
    Laptop,
    Tablet
}}

这是我对 MainWindow 的实现

public partial class MainWindow : Window
{
    public SQLiteConnection m_db = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;");
    ObservableCollection<Userss> usersCollection = Userss.GetValues();
    public MainWindow()
    {
        InitializeComponent();
    }
    private void LoadButton_Click(object sender, RoutedEventArgs e)
    {
        try
        {
            dataGrid.ItemsSource = Userss.GetValues();

        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.ToString());
        }
    }

    private void Update_Click(object sender, RoutedEventArgs e)
    {
        if (MessageBox.Show("Are you sure you want to make those changes?", "Please confirm", MessageBoxButton.YesNo) == MessageBoxResult.Yes)
        {
            try
            {
                m_db.Open();
                foreach (var user in usersCollection)
                {
                    string sql = "UPDATE user SET Name = @name, Sex = @sex, Station = @station, Job = @job, Date = @date WHERE Id = @id";
                    SQLiteCommand command = new SQLiteCommand(sql, m_db);
                    command.Parameters.Add(new SQLiteParameter("@name", user.Name));
                    command.Parameters.Add(new SQLiteParameter("@sex", user.Sex.ToString()));
                    command.Parameters.Add(new SQLiteParameter("@station", user.Station.ToString()));
                    command.Parameters.Add(new SQLiteParameter("@job", user.Job.ToString()));
                    command.Parameters.Add(new SQLiteParameter("@date", user.Date.ToString()));
                    command.Parameters.Add(new SQLiteParameter("@id", user.Id.ToString()));
                    command.ExecuteNonQuery();
                }
                m_db.Close();
                usersCollection = Userss.GetValues();
                dataGrid.Items.Refresh();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        else
            this.dataGrid.CancelEdit();
    }

    private void CancelClick(object sender, RoutedEventArgs e)
    {
        if (MessageBox.Show("Are you sure you want to cancel those changes?", "Please confirm", MessageBoxButton.YesNo) == MessageBoxResult.Yes)
        {
            dataGrid.ItemsSource = Userss.GetValues();
        }
        else
            this.dataGrid.CancelEdit();
    }
}

我遇到的问题是，当我按下 Update Button 时，我更改的值会在 database 中更新，但如果我尝试删除或添加一行，则不会发生更新在database。 注意：我尝试过使用DataSets 和Adapters，但没有成功（我相信是因为我将ComboBoxes 放入了DataGrid。 有什么想法可以在我的代码中更改吗？

Answer 1

您必须在 DataGrid 中实现特定事件。 例如：

<DataGrid ItemsSource="{Binding Userss.UserCol, Mode=TwoWay, 
          UpdateSourceTrigger=PropertyChanged}"
          DataContext="{Binding RelativeSource={RelativeSource Self}}"
          RowEditEnding="DataGrid_RowEditEnding">

所以在你的代码后面：

private void DataGrid_RowEditEnding(object sender, DataGridRowEditEndingEventArgs e)
{
    // Only act on Commit
    if (e.EditAction == DataGridEditAction.Commit)
    {
        //execute your update SQL
    }
}

对于删除很相似：

将此添加到 xlmns：

xmlns:ic="clr-namespace:System.Windows.Input;assembly=PresentationCore" 

所以在你的数据网格中：

<DataGrid 
    ItemsSource="{Binding Userss.UserCol, Mode=TwoWay, 
                     UpdateSourceTrigger=PropertyChanged}"
        DataContext="{Binding RelativeSource={RelativeSource Self}}"
        RowEditEnding="DataGrid_RowEditEnding"
        ic:CommandManager.PreviewExecuted="DataGrid_OnPreviewExecuted">

在代码隐藏中：

private void DataGrid_OnPreviewExecuted(object sender, ExecutedRoutedEventArgs e)
{
    if (e.Command == DataGrid.DeleteCommand)
    {
        // Show MessageBox and get result
        if (result == No)
        {
            // Cancel Delete command by setting Handled = true
            e.Handled = true;
        }
        else
        {
            // execute you delete SQL       
        }
    }
}

Answer 2

您只提供更新数据库中数据的更新命令，而不提供插入和删除命令。尝试以同样的方式使用 SQLiteDataAdapter：

        adapter = new SQLiteDataAdapter();

        selcmd = new SQLiteCommand();
        selcmd.CommandText = "...";
        adapter.SelectCommand = selcmd;

        upcmd = new SQLiteCommand();
        upcmd.CommandText = "...";
        adapter.UpdateCommand = upcmd;

        delcmd = new SQLiteCommand();
        delcmd.CommandText = "...";
        adapter.DeleteCommand = delcmd;

        inscmd = new SQLiteCommand();
        inscmd.CommandText = "...";
        adapter.InsertCommand = inscmd;