WPF DataGrid Navision functionality

Question

I'm working on creating a DataGrid with the same functionality as Microsoft Dynamic Nav.
This is almost like a Excel spreadsheet.

The idea is that you can start editing a cell. After you are done there are some steps:

The content of the cell is validated against a list.
1.1 If the list contains the given string (Not case sensitive), then the content in the DataGrid is replaced with the string from the list (aka the one where the case is right).
1.2 If the list doesn't contain the string it will show a new form with possibilities, and then use the one that the user selects to replace the one already typed into the DataGrid.
If the user has typed something right or selected a correct value from the list, then the DataGrid will automatic fill some columns with pre-set string

If we look at an example: If the user types z in column 1 then i want column 2 to become "x" and the focus to move to colum3

DataGrid: (Before enter/Tab pressed)

[Column1] [Column2] [Column3] [Column4]
[  "a"  ] [  "b"  ] [  "c"  ] [  "d"  ]
[  "z"  ] [       ] [       ] [       ]
(focused)

DataGrid: (Afture enter/tab pressed
[Column1] [Column2] [Column3] [Column4]
[  "a"  ] [  "b"  ] [  "c"  ] [  "d"  ]
[  "z"  ] [  "x"  ] [       ] [       ]
                    (focused)

Here I encounter some problems:

I use the CellEditEnding event to validate the text input. If I find the correct text then I edit the currentItem at the correct variable. But now I need to call dataGrid1.Items.Refresh(); and than can't be done while in edit mode.

MyCode:

FormTest.xaml

...
<DataGrid.Columns>
    <DataGridTextColumn Header="C1" 
        Binding="{Binding c1,UpdateSourceTrigger=LostFocus}"/>
    <DataGridTextColumn Header="C2" 
        Binding="{Binding c2,UpdateSourceTrigger=LostFocus}"/>
    <DataGridTextColumn Header="C3" 
        Binding="{Binding c3,UpdateSourceTrigger=LostFocus}"/>
    <DataGridTextColumn Header="C4" 
        Binding="{Binding c4,UpdateSourceTrigger=LostFocus}"/>
    <DataGridTextColumn Header="C5" 
        Binding="{Binding c5,UpdateSourceTrigger=LostFocus}"/>
</DataGrid.Columns>
...

FormTest.xaml.cs

public FormTest()
{
    InitializeComponent();
    loadMockData();
}
private void loadMockData()
{
    dataItems = new DataItems();
    dataItems.Add(new DataItem() { c1 = "a", c2 = "b", c3 = "c", c4 = "d", c5 = "e" });
    dataItems.Add(new DataItem() { c1 = "a", c2 = "b", c3 = "c", c4 = "d", c5 = "e" });
    dataItems.Add(new DataItem() { c1 = "a", c2 = "b", c3 = "c", c4 = "d", c5 = "e" });
    dataItems.Add(new DataItem() { c1 = "a", c2 = "b", c3 = "c", c4 = "d", c5 = "e" });
    dataItems.Add(new DataItem() { c1 = "a", c2 = "b", c3 = "c", c4 = "d", c5 = "e" });

    dataGrid1.ItemsSource = dataItems;
}
private void dataGrid1_CellEditEnding(object sender, DataGridCellEditEndingEventArgs e)
{
    TextBox editElement = e.EditingElement as TextBox;
    DataItem di = dataGrid1.CurrentItem as DataItem;
    DataGridCellInfo cell = dataGrid1.CurrentCell;
    if (e.Column.DisplayIndex == 0)
    {
        if (editElement.Text == "z")
        {
            editElement.Text = "Z"; 
            di.c1 = "Z";
            di.c2 = "X";
        }
    }
}
private void dataGrid1_PreviewKeyDown(object sender, KeyEventArgs e)
{
    if (e.Key == Key.Enter || e.Key == Key.Tab)
    {
        dataGrid1.CommitEdit();
        DataItem di = dataGrid1.CurrentItem as DataItem;
        dataGrid1.CancelEdit();
        dataGrid1.Items.Refresh();
     }
}

private class DataItems : List<DataItem> { }
private class DataItem
{
    public int recID { get; set; }
    public String c1 { get; set; }
    public String c2 { get; set; }
    public String c3 { get; set; }
    public String c4 { get; set; }
    public String c5 { get; set; }
}

The problems I encounter in this code are:

After the refresh is called, there is no selected cell. That means it is not possible to continue entering data without using the mouse to select a cell.
When I start typing a new item (aka the empty row), and press enter or tab, the dataGrid1.CancelEnding() will remove the new item, and the row is empty again.

The Questions

Is it possible to edit the content of the datagrid (The ItemSoure and what is displayed) without calling Items.Refresh() ?
If not is it possible to set a cell focus after the Items.Refresh() is done. ?
Or is there a better way of doing this ?

Luke Woodward Luke Woodward · Accepted Answer · 2011-07-20T13:19:12

I can answer your question about updating the content of the grid.

Normally, it's not necessary to refresh the entire grid following a change of one property. (It's also rather wasteful if you've got a lot of data in your grid.) If your class DataItem implements the INotifyPropertyChanged interface, and you fire a PropertyChanged event every time the value of one of its properties changes, WPF will update the data in the table automatically.

This page on MSDN contains an example of implementing this interface, and you can find a more complete example of the use of this interface here.

This should get rid of the need to use the dataGrid1_PreviewKeyDown event handler, which in turn gets rid of the problem with not being able to add a new row to the bottom of the grid.

You should also add Mode=TwoWay to the Bindings in your DataGridTextColumns. Otherwise, when you edit a cell, WPF won't update the relevant DataItem object with the values you enter in the grid.

I had a look at a number of approaches to 'tab' over the second column after entering a value in the first column, but alas I didn't manage to find anything that worked.

WPF DataGrid Navision functionality

The problems I encounter in this code are:

The Questions

1 Answers