wpf mvvm displaying observable collection in datagrid

问题

I need to display all the information of an object in a DataGrid

ItemsCollectionA, ItemsCollectionB and ItemsCollectionC are all ObservableCollections.

I have a datagrid:

<DataGrid ItemsSource="{Binding Path=itemscollectionA}" HeadersVisibility="All" />

This displays all properties in grid format but the ItemsCollectionB and ItemsCollectionC are appearing as (collection).

How can I get ItemsCollectionB and ItemsCollectionC to expand the grid downward and out to show their properties as well

回答1:

If you can specify the columns instead of auto-generating them, this could be very easy.

Here's an example:

<DataGrid ItemsSource="{Binding Employees}" AutoGenerateColumns="False">
    <DataGrid.Columns>
        <DataGridTextColumn Binding="{Binding EmployeeName}"/>
        <!-- Displays the items of the first collection-->
        <DataGridTemplateColumn>
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <ListBox ItemsSource="{Binding Dogs}"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>

        <!-- Displays the items of the second collection-->
        <DataGridTemplateColumn>
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <ListBox ItemsSource="{Binding Cats}"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>

ViewModel:

public class MainWindowViewModel : NotificationObject
{
    public MainWindowViewModel()
    {
        Employees = new ObservableCollection<Employee>
        {
            new Employee { EmployeeName = "Steven"},
            new Employee { EmployeeName = "Josh"},
        };
    }

    public ObservableCollection<Employee> Employees { get; set; }
}

Models:

public class Employee
{
    public Employee()
    {
        Dogs = new ObservableCollection<Dog>
        {
            new Dog { Gender = 'M'},
            new Dog { Gender = 'F'},
        };
        Cats = new ObservableCollection<Cat>
        {
            new Cat { Name = "Mitzy" , Kind = "Street Cat"},
            new Cat { Name = "Mitzy" , Kind = "House Cat"}
        };
    }

    public string EmployeeName { get; set; }

    public ObservableCollection<Dog> Dogs { get; set; }

    public ObservableCollection<Cat> Cats { get; set; }
}

public class Dog
{
    public char Gender { get; set; }

    public override string ToString()
    {
        return "Dog is a '" + Gender + "'";
    }
}

public class Cat
{
    public string Name { get; set; }

    public string Kind { get; set; }

    public override string ToString()
    {
        return "Cat name is " + Name + " and it is a " + Kind;
    }
}

Consider ItemsCollectionA as Employees and ItemsCollectionB and ItemsCollectionC as Dogs and Cats. It still uses the ToString to display the Dogs and Cats object's that I overridden, But you can simply set a DataTemplate to the listBox's within the columns to decide how to display your models. Also notice the AutoGenerateColumns="False" on the DataGrid to avoid creating the columns twice.

Hope this helps

回答2:

A DataGrid can only manage one item source. Everything is row based and the columns are not that intelligent.

Two ways:

• to combine your data into a new object with both sets of fields (would be the easiest).
• synchronise 2 datagrids side-by-side.

回答3:

Ok it seems like datagrid was entirely the wrong thing I needed here. I made a stackpanel of listbox with the itemssource set to each binding and it's displaying fine

<StackPanel Background="white" HorizontalAlignment="Stretch"  Margin="0">
        <ListBox Background="white" x:Name="BetsListBox"  VerticalAlignment="Stretch" BorderThickness="0" 
                     ItemsSource="{Binding Path=ItemsCollectionA}" Margin="0" Width="Auto" HorizontalAlignment="Stretch" >
            <ListBox.Resources>
                <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="#F0F0F0"/>
                <SolidColorBrush x:Key="{x:Static SystemColors.ControlBrushKey}" Color="#F0F0F0"/>
                <SolidColorBrush x:Key="{x:Static SystemColors.HighlightTextBrushKey}" Color="Black"/>
            </ListBox.Resources>
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel >
                        <ListBox ItemsSource="{Binding Path=ItemsCollectionB}">
                            <ListBox.ItemTemplate>
                                <DataTemplate>
                                    <StackPanel Orientation="Horizontal">
                                        <TextBlockText="{Binding Path=varA}" />
                                        <TextBlockText="{Binding Path=varB}" />
                                        <TextBlockText="{Binding Path=varC}" />
                                    </StackPanel>
                                </DataTemplate>
                            </ListBox.ItemTemplate>
                        </ListBox>
                        <ListBox BorderThickness="0" ItemsSource="{Binding Path=ItemsCollectionC}" >
                            <ListBox.ItemTemplate>
                                <DataTemplate>
                                    <StackPanel  Orientation="Horizontal" >
                                        <TextBlock Text="{Binding Path=VarA}" ToolTip="{Binding Name}"/>
                                        <TextBlock Text="{Binding Path=VarB}" ToolTip="{Binding Name}"/>
                                        <TextBlock Text="{Binding Path=VarC}" ToolTip="{Binding Name}"/>
                                    </StackPanel>
                                </DataTemplate>
                            </ListBox.ItemTemplate>
                        </ListBox >
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </StackPanel>

来源：https://stackoverflow.com/questions/19768550/wpf-mvvm-displaying-observable-collection-in-datagrid