来自命令/ viewmodel的WPF DataGridView键盘焦点

时间:2015-03-16 14:38:58

标签: .net wpf datagridview wpfdatagrid

网上到处都是类似的问题,我也搜索过(最接近:[1],[2],[3])。

到目前为止,我无法相信这个问题是丑陋/不平凡的。

我有一个DataGridView。我有其他控件(在这种情况下:在DataGridView的列标题中)。我想支持一个快速的“跳转到网格”命令。此命令需要将键盘焦点设置为网格,以便用户可以使用箭头键在行之间导航。

在下面的家中玩琐碎的测试包。在数据网格中选择一个元素非常容易,但似乎没有一种方法可以让它成为键盘焦点。除了代码隐藏操作,即使这样你似乎必须跳过篮球(见[2],玩杂耍让细胞容器设置键盘焦点,因为..网格和行似乎并不适用于所有我可以告诉)。

看起来很简单?

一些琐碎的模型:

public class Item
{
    public int DayOfMonth { get; set; }
    public string Weekday { get; set; }
}

匹配简单的viewmodel(假设你有一个RelayCommand实现,请参阅JumpToGrid~~ meat~):

public class MainViewModel : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    private IList<Item> m_items;
    public IList<Item> SampleItems
    {
        get { return m_items; }
        set { SetField(ref m_items, value, () => SampleItems); }
    }

    private Item m_currentItem;
    public Item CurrentItem
    {
        get { return m_currentItem; }
        set { SetField(ref m_currentItem, value, () => CurrentItem); }
    }

    public ICommand JumpToGridCommand { get; private set; }

    public MainViewModel()
    {
        JumpToGridCommand = new RelayCommand(p => JumpToGrid());

        var items = new List<Item>();
        var today = DateTime.Now;
        for (int i = 1; i <= DateTime.DaysInMonth(today.Year, today.Month); i++ )
        {
            items.Add(new Item { DayOfMonth = i, Weekday = new DateTime(today.Year, today.Month, i).DayOfWeek.ToString() });
        }
        SampleItems = items;
    }

    private void JumpToGrid()
    {
        // I can change the selection just fine
        CurrentItem = SampleItems[0];

        // But the keyboard focus is broken, up/down doesn't work as expected
    }

    protected bool SetField<T>(ref T field, T value, Expression<Func<T>> selectorExpression)
    {
        if (selectorExpression == null) throw new ArgumentNullException("selectorExpression");
        MemberExpression body = selectorExpression.Body as MemberExpression;
        if (body == null) throw new ArgumentException("The body must be a member expression");
        var fieldName = body.Member.Name;

        if (EqualityComparer<T>.Default.Equals(field, value)) return false;
        field = value;
        OnPropertyChanged(fieldName);
        return true;
    }

    protected void OnPropertyChanged(string propertyName)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

简单视图(除了加载的事件中的“DataContext = new MainViewModel()”之外,代码隐藏是空的): <Window x:Class="DataGridKeyboardFocus.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:DataGridKeyboardFocus" Loaded="Window_Loaded" Title="MainWindow" Height="350" Width="525"> <Grid> <DataGrid ColumnWidth="*" AutoGenerateColumns="False" Margin="1" ItemsSource="{Binding SampleItems}" SelectedItem="{Binding CurrentItem, Mode=TwoWay}" SelectionUnit="FullRow" IsReadOnly="True"> <DataGrid.Columns> <DataGridTextColumn Binding="{Binding DayOfMonth}"> <DataGridTextColumn.HeaderTemplate> <DataTemplate> <StackPanel Orientation="Vertical"> <TextBlock Text="Some label" /> <TextBox> <TextBox.InputBindings> <KeyBinding Modifiers="Control" Key="Tab" Command="{Binding DataContext.JumpToGridCommand, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type local:MainWindow}}}" /> </TextBox.InputBindings> </TextBox> </StackPanel> </DataTemplate> </DataGridTextColumn.HeaderTemplate> </DataGridTextColumn> <DataGridTextColumn Binding="{Binding Weekday}"> <DataGridTextColumn.HeaderTemplate> <DataTemplate> <StackPanel Orientation="Vertical"> <TextBlock Text="Another label" /> <TextBox> <TextBox.InputBindings> <KeyBinding Modifiers="Control" Key="Tab" Command="{Binding DataContext.JumpToGridCommand, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type local:MainWindow}}}" /> </TextBox.InputBindings> </TextBox> </StackPanel> </DataTemplate> </DataGridTextColumn.HeaderTemplate> </DataGridTextColumn> </DataGrid.Columns> </DataGrid> </Grid> </Window>

1:Keyboard focus vs logical focus in WPF

2:Keyboard focus to DataGrid

3:WPF: Can't control keyboard focus

1 个答案:

答案 0 :(得分:4)

我为网格添加了选择更改事件并尝试选择一个单元格。请参阅以下代码。

 <DataGrid
            ColumnWidth="*" 
            AutoGenerateColumns="False"
            Margin="1"
            ItemsSource="{Binding SampleItems}" 
            SelectedItem="{Binding CurrentItem, Mode=TwoWay}"
            SelectionUnit="FullRow"
            IsReadOnly="True"
        SelectionChanged="DataGrid_SelectionChanged">
        <DataGrid.Columns>
            <DataGridTextColumn Binding="{Binding DayOfMonth}">
                <DataGridTextColumn.HeaderTemplate>
                    <DataTemplate>
                        <StackPanel Orientation="Vertical">
                            <TextBlock Text="Some label" />
                            <TextBox>
                                <TextBox.InputBindings>
                                    <KeyBinding Modifiers="Control" Key="T" Command="{Binding DataContext.JumpToGridCommand, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}" />
                                </TextBox.InputBindings>
                            </TextBox>
                        </StackPanel>
                    </DataTemplate>
                </DataGridTextColumn.HeaderTemplate>
            </DataGridTextColumn>
            <DataGridTextColumn Binding="{Binding Weekday}">
                <DataGridTextColumn.HeaderTemplate>
                    <DataTemplate>
                        <StackPanel Orientation="Vertical">
                            <TextBlock Text="Another label" />
                            <TextBox>
                                <TextBox.InputBindings>
                                    <KeyBinding Modifiers="Control" Key="T" Command="{Binding DataContext.JumpToGridCommand, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}" />
                                </TextBox.InputBindings>
                            </TextBox>
                        </StackPanel>
                    </DataTemplate>
                </DataGridTextColumn.HeaderTemplate>
            </DataGridTextColumn>
        </DataGrid.Columns>
    </DataGrid>

代码背后。

private void DataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        DataGrid dg = sender as DataGrid;
        SelectRowByIndex(dg, dg.SelectedIndex);
    }
    public static DataGridCell GetCell(DataGrid dataGrid, DataGridRow rowContainer, int column)
    {
        if (rowContainer != null)
        {
            DataGridCellsPresenter presenter = FindVisualChild<DataGridCellsPresenter>(rowContainer);
            if (presenter == null)
            {
                /* if the row has been virtualized away, call its ApplyTemplate() method
                 * to build its visual tree in order for the DataGridCellsPresenter
                 * and the DataGridCells to be created */
                rowContainer.ApplyTemplate();
                presenter = FindVisualChild<DataGridCellsPresenter>(rowContainer);
            }
            if (presenter != null)
            {
                DataGridCell cell = presenter.ItemContainerGenerator.ContainerFromIndex(column) as DataGridCell;
                if (cell == null)
                {
                    /* bring the column into view
                     * in case it has been virtualized away */
                    dataGrid.ScrollIntoView(rowContainer, dataGrid.Columns[column]);
                    cell = presenter.ItemContainerGenerator.ContainerFromIndex(column) as DataGridCell;
                }
                return cell;
            }
        }
        return null;
    }
    public static T FindVisualChild<T>(DependencyObject obj) where T : DependencyObject
    {
        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i++)
        {
            DependencyObject child = VisualTreeHelper.GetChild(obj, i);
            if (child != null && child is T)
                return (T)child;
            else
            {
                T childOfChild = FindVisualChild<T>(child);
                if (childOfChild != null)
                    return childOfChild;
            }
        }
        return null;
    }
    public static void SelectRowByIndex(DataGrid dataGrid, int rowIndex)
    {
        DataGridRow row = dataGrid.ItemContainerGenerator.ContainerFromIndex(rowIndex) as DataGridRow;
        if (row != null)
        {
            DataGridCell cell = GetCell(dataGrid, row, 0);
            if (cell != null)
                cell.Focus();
        }
    }

请参阅链接。 http://social.technet.microsoft.com/wiki/contents/articles/21202.wpf-programmatically-selecting-and-focusing-a-row-or-cell-in-a-datagrid.aspx