C＃WPF KeyDown高亮显示+选中数据网格中的最后一行

Question

I'm working on application where user can add products to a datagrid, with simple informations like product name and price, and after that I would like to for example press F4 key on my keyboard and I would like to focus on last item in datagrid, that means select it and HIGHLIGHT that item!

So guys how could I achieve that, I've tried few solutions like setting selected index to my datagrid and smth like that, but it is not working

Thanks guys, Cheers

Answer 1

Programmatically highlighting a row or cell in a DataGrid is a bit more complicated than just setting the SelectedIndex or SelectedItem property.

It is however possible to select and focus a row in code and get the same behaviour as when using the mouse by accessing the visual user interface elements of the DataGrid control and calling the UIElement.Focus() method on a particular DataGridCell object as described in the following blog post.

How to programmatically select and focus a row or cell in a DataGrid in WPF: https://blog.magnusmontin.net/2013/11/08/how-to-programmatically-select-and-focus-a-row-or-cell-in-a-datagrid-in-wpf/

Here is an example:

public partial class MainWindow : Window
{
    public MainWindow
    {
        InitializeComponent();
        this.PreviewKeyDown += (s, e) => 
        {
            if(e.Key == Key.F4)
                SelectRowByIndex(dataGridProducts, dataGridProducts.Items.Count - 1);
        };

        //populate DataGrid etc...
    }

    private static void SelectRowByIndex(DataGrid dataGrid, int rowIndex)
    {
        if (!dataGrid.SelectionUnit.Equals(DataGridSelectionUnit.FullRow))
            throw new ArgumentException("The SelectionUnit of the DataGrid must be set to FullRow.");

        if (rowIndex < 0 || rowIndex > (dataGrid.Items.Count - 1))
            throw new ArgumentException(string.Format("{0} is an invalid row index.", rowIndex));

        dataGrid.SelectedItems.Clear();
        object item = dataGrid.Items[rowIndex];
        dataGrid.SelectedItem = item;

        DataGridRow row = dataGrid.ItemContainerGenerator.ContainerFromIndex(rowIndex) as DataGridRow;
        if (row == null)
        {
            /* bring the data item (Product object) into view
             * in case it has been virtualized away */
            dataGrid.ScrollIntoView(item);
            row = dataGrid.ItemContainerGenerator.ContainerFromIndex(rowIndex) as DataGridRow;
        }
        if (row != null)
        {
            DataGridCell cell = GetCell(dataGrid, row, 0);
            if (cell != null)
                cell.Focus();
        }
    }

    private static DataGridCell GetCell(DataGrid dataGrid, DataGridRow rowContainer, int column)
    {
        if (rowContainer != null)
        {
            System.Windows.Controls.Primitives.DataGridCellsPresenter presenter 
                = FindVisualChild<System.Windows.Controls.Primitives.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<System.Windows.Controls.Primitives.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;
    }

    private 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;
    }
}

Answer 2

You can use an InputBinding to recognize the pressed F4 Key.

<Window.InputBindings>
    <KeyBinding Key="F4"
                Command="{Binding SelectLastItemCommand}" />
</Window.InputBindings>

You can have a look here for how to select the item: WPF Binding SelectedItem in DataGrid

Answer 3

Where does your problem lie? With handling the button event or highlighting the row? It seems like its the latter, so have a look at this: https://www.codeproject.com/Tips/773382/Row-Highlighting-in-WPF-Grids