WPF DataGrid 分组数据

Question

Here's an article I found on the web to hroupe datas in a WPF Datagrid: Grouping in DataGrid in WPF

I want to test it in a WPF application with data coming from an Entity Framework DataContext . First I want to check that data are correctly implemented in the DataGrid . But the DataGrid stays empty. Here's may xaml :

 <UserControl x:Class="GESTION_CONGELATION_V2.User_Controls.ViewPvi_UC" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignHeight="450" d:DesignWidth="800"> <DataGrid x:Name="Pvi_DT"> </DataGrid> </UserControl>

My .cs

public partial class ViewPvi_UC : UserControl
{
    ObservableCollection<VW_PVI_2> pvi = new ObservableCollection<VW_PVI_2>();
    public ViewPvi_UC()
    {
        InitializeComponent();
        ObservableCollection<VW_PVI_2> pvi = new ObservableCollection<VW_PVI_2>();
        Pvi_DT.ItemsSource = pvi;
    }
}

and my Entity Framework class

public partial class VW_PVI_2
{
    public int PVI_ID { get; set; }
    public string VE_NOM { get; set; }
    public string VD_VIRTUAL { get; set; }
    public string VE_OLD_NAME { get; set; }
    public string ST_LIB { get; set; }
    public string VE_COMM { get; set; }
    public string IMP_NOM { get; set; }
    public string IMP_IP { get; set; }
    public string IMP_MAC { get; set; }
    public string ST_LIB_IMP { get; set; }
    public string IMP_COMM { get; set; }
    public string SERV_NOM { get; set; }
    public string PO_NOM { get; set; }
}

and the result in the datagrid

Answer 1

You can change your the pvi declaration as following, to use the ICollectionView :

public partial class ViewPvi_UC : UserControl
{
    public ICollectionView pvi { get; set; }
    public ViewPvi_UC()
    {
        InitializeComponent();      
    }

    async private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        await Task<object>.Factory.StartNew(() =>
        {
            // Select all `VW_PVI_2` from your table here to be populate the `pvi`
            IList<VW_PVI_2> data= YourDbContext.YourTable.Select(r => r).ToList();
            pvi = new ObservableCollection<VW_PVI_2>(data);
            this.Dispatcher.Invoke(() => {  Pvi_DT.ItemsSource = pvi; });
            return Task.FromResult<object>(null);
        });
    }
}

Adding the Loaded event in the XAML:

<UserControl ...
    d:DesignHeight="450" d:DesignWidth="800"
    Loaded="Window_Loaded">
    <DataGrid x:Name="Pvi_DT">
        
    </DataGrid>
</UserControl>

Loading the data from a table is moved to the Loaded event handler and performing asynchronously. Because of loading data can take some time. Therefore is is possible to implement some logic to show a message that loading data is performing to indicate the user about this process.

In case you want to hide some columns (for example PVI_ID ) it is possible to use a custom attribute:

public class HiddenAttribute : Attribute
{
}

public partial class VW_PVI_2
{
    [Hidden]
    public int PVI_ID { get; set; }
    ...
}

Then add the AutoGeneratingColumn event handler declaration to the dataGrid to the XAML:

<DataGrid x:Name="dataGrid1" AutoGeneratingColumn="Pvi_DT_AutoGeneratingColumn"/>

And the handler declaration to hide some columns:

private void Pvi_DT_AutoGeneratingColumn(object sender, DataGridAutoGeneratingColumnEventArgs e)
{
    if (e.PropertyDescriptor is PropertyDescriptor prop && prop.Attributes.OfType<HiddenAttribute>().Any())
    {
        e.Cancel = true;
    }
}