XAML将可观察的集合绑定到DataGrid

Question

I'm having trouble databinding based on other properties. My combobox is working fine, but the datagrids aren't. I'm was trying to bind the window to the codebehind using DataContext="{Binding RelativeSource={RelativeSource Self}}" so I could have design time Intellisense, but I sort of got it using x:Name:"_Window"

The model for HRRM has lots of entities, and I know that that the properties I'm trying to bind too are spelt correctly etc. But I can't figure out why the DataGrid won't show the employees. I've also ensured that the data is being placed in the observable collection, and I've tried binding the items source just to ListEmployees and SmsEmployees and nothing I've tried has worked. This is the last bit of code I have tried.

<Window x:Class="GUI.Employees.Misc.SendSms"
    x:Name="_Window"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Send SMS" Height="525" Width="1000" DataContext="{Binding ElementName=_Window}">

<Grid>

    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="270*" />
        <ColumnDefinition Width="150" />
        <ColumnDefinition Width="270*" />
    </Grid.ColumnDefinitions>
    <ComboBox Grid.Column="0" x:Name="cmbCompany" DisplayMemberPath="Name" ItemsSource="{Binding Path=Companies, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window}}"  Margin="10,10,10,0" VerticalAlignment="Top" SelectionChanged="cmbCompany_SelectionChanged"/>
    <DataGrid Grid.Column="0" x:Name="dgEmployees" Margin="10,37,10,10" IsReadOnly="True"  AutoGenerateColumns="False" ItemsSource="{Binding Path=ListEmployees, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window} }">
        <DataGrid.Columns>
            <DataGridTextColumn Header="Company" Binding="{Binding HRCo }"/>
            <DataGridTextColumn Header="First Name" Binding="{Binding FirstName}" />
            <DataGridTextColumn Header="Last Name" Binding="{Binding LastName}"/>
            <DataGridTextColumn Header="Craft" Binding="{Binding StdCraft}"/>
        </DataGrid.Columns>
    </DataGrid>
    <DataGrid x:Name="dgSendSms" Margin="10,37,10,10" IsReadOnly="True" Grid.Column="2" ItemsSource="{Binding  SmsEmployees, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window} }">
        <DataGrid.Columns>
            <DataGridTextColumn Header="Company" Binding="{Binding HRCo}"/>
            <DataGridTextColumn Header="First Name" Binding="{Binding FirstName}" />
            <DataGridTextColumn Header="Last Name" Binding="{Binding LastName}"/>
            <DataGridTextColumn Header="Craft" Binding="{Binding StdCraft}"/>
        </DataGrid.Columns>
    </DataGrid>
    <Button x:Name="cmdMoveAllHired" Content="&gt;&gt;" Margin="10,85,10,0" VerticalAlignment="Top" Grid.Column="1"
            Click="cmdMoveAllHired_Click" />
    <Button x:Name="cmdReturnSingleItem" Content="&gt;" Margin="10,122,10,0" VerticalAlignment="Top"
            Grid.Column="1"  Click="cmdReturnSingleItem_Click" />
    <Button x:Name="cmdMoveAllReturned" Content="&lt;&lt;" Margin="10,196,10,0" VerticalAlignment="Top"
            Grid.Column="1"  Click="cmdMoveAllReturned_Click" />
    <Button x:Name="cmdHireSingleItem" Content="&lt;" Margin="10,159,10,0" VerticalAlignment="Top" Grid.Column="1"
             Click="cmdHireSingleItem_Click" />
    <Button x:Name="cmdGenerate" Content="Generate" Grid.Column="1" Margin="10,0,10,10"
            VerticalAlignment="Bottom" Click="cmdGenerate_Click" Visibility="Collapsed" />
    <Button x:Name="cmdBack" Content="Back" Grid.Column="1" HorizontalAlignment="Left" Margin="10,249,0,0"
            VerticalAlignment="Top" Width="130" Click="cmdBack_Click" />

    <Button x:Name="cmdSendSMS" Content="Send SMS" Grid.Column="1" HorizontalAlignment="Left" Margin="10,316,0,0" VerticalAlignment="Top" Width="130" Click="cmdSendSMS_Click"/>

</Grid>

namespace GUI.Employees.Misc
{
public partial class SendSms
{
    public ObservableCollection<HQCO> Companies { get; set; }

    public ObservableCollection<HRRM> ListEmployees { get; set; }

    private ObservableCollection<HRRM> _smsEmployees;

    public ObservableCollection<HRRM> SmsEmployees {
        get { return _smsEmployees; }
        set { _smsEmployees = value;
        }
    }

    public SendSms()
    {
        InitializeComponent();
        Companies = new ObservableCollection<HQCO>(HQCO.GetActivePRCompanies());
        Companies.Insert(0, new HQCO { HQCo = 0, Name = "All" });
        // cmbCompany.SelectedItem = _companies.Single(x=>x.HQCo == 0);
        SmsEmployees = new ObservableCollection<HRRM>();
        ChangeCompany();
    }
    private void ChangeCompany()
    {
        if (((HQCO)cmbCompany.SelectedItem)?.HQCo == 0)
            foreach (var co in Companies)
                co.IsChecked = true;
        else
            foreach (var co in Companies)
                if (((HQCO)cmbCompany.SelectedItem) == co)
                    co.IsChecked = true;
                else
                    co.IsChecked = false;

        ListEmployees = new ObservableCollection<HRRM>(Facade.GetEmployeePhoneNumbers(Companies.ToList(), false).OrderBy(x => x.SortName));
    }
}

Answer 1

I don't believe your ListEmployees ItemsSource will update the DataGrid because it is not a DependencyProperty or you have not implemented INotifyPropertyChanged . It is not updating because you are assigning the property a new instance.

Instead try adding this to your constructor:

ListEmployees = new ObservableCollection<HRRM>();

And this to your ChangeCompany method:

foreach (var employee in Facade.GetEmployeePhoneNumbers(Companies.ToList(), false).OrderBy(x => x.SortName))
{
    ListEmployees.Add(employee);
}

The above will actually make use of the ObservableCollection and it should then update the UI.

Answer 2

I think your problem is how you assign the DataContext of your Window. In your XAML, add a reference to the namespace so the Window can find your SendSms viewmodel, and then either assign the DataContext property in XAML (see below), or in the code-behind of your Window. If you set the DataContext this way, you shouldnt need to use RelativeSource when binding to the SendSms viewmodel, but if you want see changes, you also need to make sure the classes your observable collections are populated with implements INotifyPropertyChanged.

<Window x:Name="_Window"
        xmlns:local="clr-namespace:GUI.Employees.Misc" >

 <!--  set the DataContext of this Window to an instance of SendSms  -->
<Window.DataContext>
    <local:SendSms />
</Window.DataContext>

<DataGrid ItemsSource="{Binding ListEmployees}">
   ...
</DataGrid>