Question

我正在开发一个WPF应用程序，其中包含一个DataGrid，其中包含姓名，姓氏，电子邮件等人员详细信息。

我使用ObservableCollection列表DataSource作为DataGrid：

public ObservableCollection<Persons> personsLists = new ObservableCollection<Person>(Controller.SelectAllPersons());

接下来我想要实现的目标是：

例如，当我更改名字或姓氏时，我将它保存到数据库，我想立即更新DataGrid。我尝试按照MSDN documentation：

实施INotifyPropertyChanged

public class Person : MyInherit, INotifyPropertyChanged
{
    #region Attributes
    private string _fullName;
    private int _townId;
    private string _firstName;
    private Town _town;
    private string _lastName;
    #endregion

    public event PropertyChangedEventHandler PropertyChanged;

    private void NotifyPropertyChanged(String propertyName = "")
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    #region Properties

    public Town Town
    {
        get { return _town; }
        set
        {
            _town = value;
            NotifyPropertyChanged("Town");
        }
    }
    public int TownId
    {
        get { return _townId; }
        set
        {
            _townId = value;
            NotifyPropertyChanged("TownId");
        }
    }

    public string FullName
    {
        get { return _fullName; }
        set
        {
            _fullName = value;
            NotifyPropertyChanged("FullName");
        }
    }

    public string FirstName
    {
        get { return _firstName; }
        set
        {
            _firstName = value;
            NotifyPropertyChanged("FirstName");
        }
    }

    public string LastName
    {
        get { return _lastName; }
        set
        {
            _lastName = value;
            NotifyPropertyChanged("LastName");
        }
    }
}

这就是我在UI表单上编辑人物对象的地方：

private void btnPersonEdit_Click(object sender, System.Windows.RoutedEventArgs e)
{
    Person selectedPerson = (Person)(dtgPersons.SelectedItem);

    if (selectedPerson != null)
    {
        //GetExistingPerson from DataGrid (gettin obj from list which is source to a DataGrid so it's same as getting it from DataGrid)
        var person = personsLists.Where(d => d.Id == selectedPerson.Id).FirstOrDefault();

        if (person != null)
        {
            person.FirstName = txtFirstName.Text;
            person.LastName = txtLastName.Text;

            person.Town = (Town)cmbTowns.SelectedItem;
            person.TownId = selectedPerson.Town.Id;

            //Apply changes to a database
            Person lastUpdated = Controller.UpdatePerson(person);

            dtgPersons.UnselectAll();
        }
    }

    //After this I thought the same item I edited should be updated immediately on a DataGrid but obviously I did something wrong
}

如何在不再设置源的情况下，使用此INotifyPropertyChanged接口更新DataGrid，因为我觉得做这样的事情对性能不利：

dtg.ItemsSource=null;
dtg.ItemsSource=  personsLists;

XAML：

<DataGrid Grid.Row="1" IsReadOnly="True" Name="dtgPersons" EnableColumnVirtualization = "True"
            EnableRowVirtualization ="True" SelectionUnit="FullRow" Background="White" Margin="0,5,0,0" 
            AutoGenerateColumns="False" RowHeaderWidth="0" MaxWidth="4000" MaxHeight="2000" HorizontalGridLinesBrush="#0091EA" 
            VerticalGridLinesBrush="#0091EA" CanUserAddRows="False" FontSize="{x:Static local:Globals.dataGridfontSizeContent}" 
            RowHeight="30" SelectionChanged="dtgPersons_SelectionChanged" >
    <DataGrid.CellStyle>
        <StaticResource ResourceKey="DataGridCentering"/>
    </DataGrid.CellStyle>
    <DataGrid.Resources>
        <Style TargetType="{x:Type DataGridColumnHeader}">
            <Setter Property="Background" Value="#0091EA"/>
            <Setter Property="Opacity" Value="1"/>
            <Setter Property="Foreground" Value="White"/>
            <Setter Property="HorizontalContentAlignment" Value="Center" />
            <Setter Property="FontSize" Value="{x:Static local:Globals.dataGridfontSizeHeader}"/>
            <Setter Property="FontFamily" Value="Arial"/>
            <Setter Property="Height" Value="40"/>
        </Style>
        <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="LightBlue"/>
    </DataGrid.Resources>   
    <DataGrid.Columns>
        <DataGridTextColumn Binding="{Binding FirstName}"   CellStyle="{StaticResource DataGridCenteringLeft}"  
            Header="First Name"   Foreground="Black" FontSize="16" FontFamily="Verdana" Width="*"  />
        <DataGridTextColumn Binding="{Binding LastName}"   CellStyle="{StaticResource DataGridCenteringLeft}"    
            Header="Last Name"   Foreground="Black" FontSize="16" FontFamily="Verdana" Width="*"  />
    </DataGrid.Columns>
</DataGrid>

Answer 1

为什么要在int集合中查找Person个对象？我想你想设置所选属性的属性：

listaselectedPerson

INotifyChanged接口没有按预期工作C＃Wpf（我第一次实现它）

1 个答案: