How to programmatically select AND focus a cell in the new WPF Datagrid

Question

It's easy to select and focus a ListViewItem within a WPF ListView using the following code:

...
myListView.SelectedItem = myListView.Items[index];
myListView.ScrollIntoView(myListView.Items[index]);
ListViewItem listViewItem = myListView.ItemContainerGenerator.ContainerFromIndex(index) as ListViewItem;
listViewItem.Focus();
...

How would you do exactly the same for the new WPF DataGrid, i.e. programmatically select a cell within the WPF DataGrid and then programmatically put the focus on that cell, so that you can then navigate through the DataGrid with the arrow keys on the keyboard? Part of the code for selecting would be:

...
myDataGrid.SelectedItem = myDataGrid.Items[index];
myDataGrid.ScrollIntoView(myDataGrid.Items[index]);
...

However, what is the code for putting the focus on the selected WPF DataGrid Cell? Thanks for any help!

Answer 1

Here is one way to set focus to a particular cell programmatically:
 
DataGridCell cell = GetCell(rowIndex, colIndex);
cell.Focus;

See, http://forums.msdn.microsoft.com/en-US/wpf/thread/63974f4f-d9ee-45af-8499-42f29cbc22ae for the implementation of GetCell().

Answer 2

Oh Great! Vincent, thank you very much for this solution that will also be helpful in other situations.

Meanwhile, I also found another way to set the focus. Perhaps this is also helpful for somebody else:

...
int index = 11;
myDataGrid.SelectedItem = myDataGrid.Items[index];
myDataGrid.ScrollIntoView(myDataGrid.Items[index]);
DataGridRow dgrow = (DataGridRow)myDataGrid.ItemContainerGenerator.ContainerFromItem(myDataGrid.Items[index]);
dgrow.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
...

Answer 3

In one approach like it I must select and highlight the row in DataGrid.
It doesn't function with dgrow.MoveFocus, but functions well with dgrow.IsSelected=True.
But if any other rows where selected before, they stay selected.
if you want to have only one row selected, you must do something like:

1.     foreach (object _rowitem in MyDataGrid.Items) {
2.         DataGridRow _visualItem = (DataGridRow)MyDataGrid.ItemContainerGenerator.ContainerFromItem(_rowitem);
3.         _visualItem.IsSelected = false;

One another problem: if ItemContainerGenerator returns Nothing. It can happen, if items where not really generated.
In the case ItemContainerGenerator.Status=NotStarted. 
For example, you create a new datagrid. It is not generated after InitializeComponent(), but only after DataGrid.Loaded event.
Then you can call your selection routine in or after DataGrid.Loaded.

Answer 4

I would like to navigate between the GridView Cells using directional keys. when user clicks on a cell and press the arrow keys then the focus has to be moved on to the next cell. I could find the Coordinates of the next cell, now with this coordinates I would like to set focus on that cell. Please help me with the code.
       

Answer 5

I haven't had much luck the other ways, so i use this workaround

//first focus the grid
grid.Focus();
//then create a new cell info, with the item we wish to edit and the column number of the cell we want in edit mode
DataGridCellInfo cellInfo = new DataGridCellInfo(itemToSelect, grid.Columns[0]);
//set the cell to be the active one
grid.CurrentCell = cellInfo;
//scroll the item into view
grid.ScrollIntoView(itemToSelect);
//begin the edit
grid.BeginEdit();

this works for me. (it would make a nice little static method too :)

Answer 6

hello everyone!

i have this probelm with programmically selecting a cell in WPF DataGrid too.
i'm using .NET 4.0 Beta 2.

i have MainWindow with DataGrid in it, for example such markup:

        <DataGrid
Name="myDataGrid"
AutoGenerateColumns="False"
GridLinesVisibility="None"
IsReadOnly="True"
SelectionUnit="Cell"
SelectionMode="Single">           
            <DataGrid.Columns>
                <!-- some columns -->               
            </DataGrid.Columns>           
        </DataGrid>

important thing is that in my DataGrid i need:

SelectionUnit="Cell"
SelectionMode="Single"

all solutions i've found (including in this thread) not works,
so i tried to do some stuff by myself, and this is what i got.

i've experimented with various proerties of DataGrid, it's event handlers, etc.

and finnaly, i looked at the property "myDataGrid.SelectedCells", in debug i find out,
that if i select only one cell, in "myDataGrid.SelectedCells" will be 1 item of type
"DataGridCellInfo", and it's "Column" proprty is not null!

so when you working with individual cells (like in my case),
all other properties like:
SelectedIndex, SelectedItem, CurrentCell, CurrentColumn, Items.*, ItemContainerGenerator.*, etc.
are useless, so you need to work with the prperty "SelectedCells" even if you are
working with a single cell.

so this is my solution wich i'm using now:

public partial class MainWindow {
    private DataGridCellInfo[,] dataGridAllCells; //here will be stored all cells, displayed in DataGrid, as 2D matrix of cells
...
        public MainWindow() {
            InitializeComponent();

//here goes important stuff, this needs to be done each time, "myDataGrid.ItemsSource" is changed and all cells are regenerated
            myDataGrid.ItemContainerGenerator.ItemsChanged += (sender, e) => {
        //init matrix of cells
        dataGridAllCells = new DataGridCellInfo[myDataGrid.Items.Count, myDataGrid.Columns.Count];
        //changing "SelectionUnit" to "CellOrRowHeader", so we can select all cells of our DataGrid
        myDataGrid.SelectionUnit = DataGridSelectionUnit.CellOrRowHeader;
        //selecting all cells
        myDataGrid.SelectAllCells();
        //getting all selected cells (with proper "Column" property)
        var allCellsArray = myDataGrid.SelectedCells.ToArray();//"ToArray()" is necessary, so we won't loose the cells during selection change
        //initialize items of our cell matrix
        for (int indexRow = 0, arrayCellsIndex = 0; indexRow < myDataGridt.Items.Count; indexRow++)           
            for (int indexColumn = 0; indexColumn < myDataGrid.Columns.Count; indexColumn++)
                dataGridAllCells[indexRow, indexColumn] = allCellsArray[arrayCellsIndex++];
        //setting back "SelectionUnit"
        myDataGrid.SelectionUnit = DataGridSelectionUnit.Cell;
            };
    }
...
        private void MoveToUpperCell_Click(object sender, RoutedEventArgs e) {
            if (myDataGrid.SelectedCells.Count == 1) {
                int indexRow = myDataGrid.Items.IndexOf(myDataGrid.SelectedCells[0].Item);//getting current selected row
                int indexColumn = myDataGrid.Columns.IndexOf(myDataGrid.SelectedCells[0].Column);//getting current selected column
                myDataGrid.SelectedCells.Clear();//clearing the selection
                myDataGrid.SelectedCells.Add(dataGridAllCells[Math.Max(--indexRow, 0), indexColumn]);//and setting new selection we need
            }
//selec some default cell if none is selected
            else myDataGrid.SelectedCells.Add(dataGridAllCells[0, 1]);
//scroll to current selection
        myDataGrid.ScrollIntoView(myDataGrid.SelectedCells[0].Item);
        }

        private void MoveToLowerCell_Click(object sender, RoutedEventArgs e) {
            if (myDataGrid.SelectedCells.Count == 1) {
                int indexRow = myDataGrid.Items.IndexOf(myDataGrid.SelectedCells[0].Item);
                int indexColumn = myDataGrid.Columns.IndexOf(myDataGrid.SelectedCells[0].Column);
                myDataGrid.SelectedCells.Clear();
                myDataGrid.SelectedCells.Add(dataGridAllCells[Math.Min(++indexRow, myDataGrid.Items.Count - 1), indexColumn]);
            }
            else myDataGrid.SelectedCells.Add(dataGridAllCells[0, 1]);
        myDataGrid.ScrollIntoView(myDataGrid.SelectedCells[0].Item);       
        }
...
}

so in this way you can programmicaly change selected cell as you need.

---

nya-nya!

Answer 7

When trying to implement the above in VB.Net 2008 with ToolKit with the following.  SetCellFocus is intended to set the focus to the designate row and column for the designated datagrid and allow input.

    Private Sub SetCellFocus(ByVal dgGrid As DataGrid, ByVal nRow As Integer, ByVal nCol As Integer)
        Dim dgCell As DataGridCell
        dgCell = GetCell(dgGrid, nRow, nCol)
        dgCell.Focus()
        dgGrid.BeginEdit()
    End Sub

    Private Function GetCell(ByRef dgGrid As DataGrid, ByVal nRow As Integer, ByVal nCol As Integer) As DataGridCell

        Dim dgRow As DataGridRow = GetRow(dgGrid, nRow)
        If dgRow IsNot Nothing Then
            Dim presenter As DataGridCellsPresenter
            presenter = GetVisualChild2(dgRow)

            Dim dgCell As DataGridCell
            dgCell = presenter.ItemContainerGenerator.ContainerFromIndex(nCol)
            If dgCell Is Nothing Then
                dgGrid.ScrollIntoView(dgRow, dgGrid.Columns(nCol))
                dgCell = presenter.ItemContainerGenerator.ContainerFromIndex(nCol)
            End If
            GetCell = dgCell
        Else
            GetCell = Nothing
        End If
    End Function

    Private Function GetRow(ByRef dgGrid As DataGrid, ByVal nRow As Integer) As DataGridRow
        Dim row As DataGridRow = dgGrid.ItemContainerGenerator.ContainerFromIndex(nRow)
        If row Is Nothing Then
            dgGrid.ScrollIntoView(dgGrid.Items(nRow))
            row = dgGrid.ItemContainerGenerator.ContainerFromIndex(nRow)
        End If
        GetRow = row
    End Function

    Function GetVisualChild2(ByRef dgRow As Visual) As DataGridCellsPresenter
        Dim v As Visual
        Dim nChildren As Integer
        Dim nChild As Integer
        Dim child As DataGridCellsPresenter

        child = Nothing
        nChildren = VisualTreeHelper.GetChildrenCount(dgRow)
        For nChild = 0 To nChildren - 1
            v = VisualTreeHelper.GetChild(dgRow, nChild)
            child = CType(v, DataGridCellsPresenter)
            If child Is Nothing Then
                child = GetVisualChild2(v)
            Else
                Exit For
            End If
        Next
        GetVisualChild2 = child
    End Function

Everything seems to be working except the GetVisualChild implementation.  The GetChildCount of dgRow returns 0.

Appreciate any help that can be provided.

Bob

Answer 8

Hello everybody

we have an important question about your solution.

Does myDataGrid.ScrollIntoView(dataObject) work in sync with UI Render Thread of WPF?

it means if we call myDataGrid.ScrollIntoView(dataObject) on the next line can we sure that ItemsContainerGenerator creates correspond DataGridRow for desired dataObject ?

it means ..

int index = 11;
myDataGrid.SelectedItem = myDataGrid.Items[index];
myDataGrid.ScrollIntoView(myDataGrid.Items[index]);
DataGridRow dgrow = (DataGridRow)myDataGrid.ItemContainerGenerator.ContainerFromItem(myDataGrid.Items[index]);

//always dgrow!=null?

 
dgrow.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));

 

thank you for your answers

http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/933b65b4-00ca-4fdd-8b15-615b8cc7c4ac/#3160bd4d-876a-4bd6-8b4b-b42d52626528

Answer 9

Thanks Aran, your solution worked for me

Answer 10

I haven't had much luck the other ways, so i use this workaround

//first focus the grid
grid.Focus();
//then create a new cell info, with the item we wish to edit and the column number of the cell we want in edit mode
DataGridCellInfo cellInfo = new DataGridCellInfo(itemToSelect, grid.Columns[0]);
//set the cell to be the active one
grid.CurrentCell = cellInfo;
//scroll the item into view
grid.ScrollIntoView(itemToSelect);
//begin the edit
grid.BeginEdit();

this works for me. (it would make a nice little static method too :)

Thanks. This works for me too. 

Answer 11

I haven't had much luck the other ways, so i use this workaround

//first focus the grid
grid.Focus();
//then create a new cell info, with the item we wish to edit and the column number of the cell we want in edit mode
DataGridCellInfo cellInfo = new DataGridCellInfo(itemToSelect, grid.Columns[0]);
//set the cell to be the active one
grid.CurrentCell = cellInfo;
//scroll the item into view
grid.ScrollIntoView(itemToSelect);
//begin the edit
grid.BeginEdit();

this works for me. (it would make a nice little static method too :)

Worked perfectly for me!! Thanks.

Answer 12

I have a new datagrid and when the user enters data in the first row the focus must be set to the beginning of second row first cell.  At this time the second row does not exist in the grid. It's added after the first row is comitted.  How can I achieve this using your code above.  Also, in your code could you explain what is itemToSelect will be?

Thanks

Ragu

Answer 13

DataGrid's CurrentCell (read/write) Property seemed the most obvious choice and surprise, surprise, actually worked for me!?!  Woo-hoo! 

NOTE: Unless you're dynamically generating the Columns, you should know, at compile time, the Name of the Column you want to Focus on.  If so, you should give that Column a non-blank Name Property (aka "x.Name" XAML Attribute) and reference it by that name in the code.  That way you avoid hard-coded Column Index Literals that are likely to break without letting you know at compile time, if you reorder / remove the Column.

FYI, I was doing this inside a Handler (inside the Code Behind of the View) of an Event Raised by an ICommand in the View Model bound to a Button in the View, so YMMV, if you're doing it using a different method.

<DataGrid x:Name="MyDatGrid"
    ...
    >
    ...
    <DataGridCheckboxColumn x:Name="TargDgCol"
        Header="Targ"
        ...
        >
        ...
    
    </DataGridCheckboxColumn> <!-- "TargDgCol" -->
    ...    
</DataGrid> <!-- "MyDatGrid" -->

With MyDatGrd 

    .CurrentCell = New DataGridCellInfo(
        .Items(TargRowIdxInt), 
        TargDgCol 
    ) 

End With ' -- MyDatGrd