WPF Datagrid允许用户添加行

Question

I want to allow the user to add rows in a datagrid. I know the Datagridview from WinForms and there is allways on the bottom of the Datagrid a empty line that i can fill with data.

<DataGrid x:Name="dgv" 
          Grid.ColumnSpan="4" 
          Grid.Row="1" 
          CanUserAddRows="True" 
          CanUserDeleteRows="True" 
          SelectionUnit="FullRow" 
          AutoGenerateColumns="False" 
          ItemsSource="{Binding Entries}">
        <DataGrid.Columns>
            <DataGridComboBoxColumn Header="Anrede" Width="1*"></DataGridComboBoxColumn>
            <DataGridTextColumn Header="Vorname" Width="2*" Binding="{Binding Vorname}" />
            <DataGridTextColumn Header="Nachname" Width="2*" Binding="{Binding Nachname}" />
        </DataGrid.Columns>
    </DataGrid>

Code behind:

public ObservableCollection<Mitreisender> Entries { get; }

public aufenthaltsWindow()
{
    InitializeComponent();
    Entries = new ObservableCollection<Mitreisender>();
}

The Class

public class Mitreisender
{
    public int MitreisenderID { get; set; }
    public Gast.AnredeTyp Anrede { get; set; }
    public string Titel { get; set; }
    public string Vorname { get; set; }
    public string Nachname { get; set; }

    public virtual Aufenthalt Aufenthalt { get; set; }

    public Mitreisender()
    {

    }
}

Answer 1

You need to set the DataGrid.ItemsSource to a modifyable collection. Suppose your DataContext contains a property

public ObservableCollection<EntryViewModel> Entries { get; }

with

class EntryViewModel // probably derive some ViewModelBase and implement INotifyPropertyChanged
{
    public string Vorname { get; set; }
    // ... other properties
}

Then bind the collection from datacontext to itemssource.

<DataGrid x:Name="dgv" ItemsSource="{Binding Entries}" ...>

With a modifyable collection and your settings, an extra line for new items will be available. You will still need to bind the columns to the actual item properties, I'm not addressing this part here.

Answer 2

Make sure that the Mitreisender class has a parameterless constructor:

public Mitreisender()
{

}

This is required for the blank "add" row to show up.

Also make sure that the binding works and that you have set the DataContext of the DataGrid or its parent window to an instance of the class where the Entries property is defined:

public aufenthaltsWindow()
{
    InitializeComponent();
    Entries = new ObservableCollection<Mitreisender>();
    DataContext = this;
}