How can I display array elements in a WPF DataGrid?

Question

I'm trying to display a series of rows in a WPF DataGrid where each row contains an array of booleans (the number of which is the same for all rows, it's not a jagged 2D array) that I want to display as individual columns, eg.

Name            | Day 1 | Day 2 | Day 3 | Day 4 | Day 5 | Day 6 |
-----------------------------------------------------------------
Bring out Trash |   X   |       |   X   |       |       |   X   |
Pay Bills       |       |       |       |       |   X   |       |
Commit Suicide  |       |       |       |       |       |   X   |

Currently, I'm using this class for my DataGrid rows:

private class GridRow {
  public string Name { get; set; }
  public char Day1 { get; set; }
  public char Day2 { get; set; }
  public char Day3 { get; set; }
  public char Day4 { get; set; }
  public char Day5 { get; set; }
  public char Day6 { get; set; }
  public char Day7 { get; set; }
  public char Day8 { get; set; }
  public char Day9 { get; set; }
}

In the real world case, make that 128 booleans. It gets the job done for the time being (for as long as nobody creates cyclic plans with a length over 128 days) but it's a rather ugly solution.

Can I somehow feed an array of booleans into the DataGrid? I've taken a look various articles on implementing ValueConverters, but I'm not sure that's what I need.

Photosynthesis

Can you not put them in a collection and then use the datagrid's databinding? – Resilience

@Tony: That is precisely what I'm trying to do. I just didn't know how to tell the WPF DataGrid how to display an element from a collection/array/whatever. – Photosynthesis

Answer 1

I think you'll have to deal with code behind for this...

Example:

Test class:

public class TestRow
{
    private bool[] _values = new bool[10];
    public bool[] Values
    {
        get { return _values; }
        set { _values = value; }
    }

    public TestRow(int seed)
    {
        Random random = new Random(seed);
        for (int i = 0; i < Values.Length; i++)
        {
            Values[i] = random.Next(0, 2) == 0 ? false : true;
        }
    }
}

How to generate test data & columns:

DataGrid grid = new DataGrid();
var data = new TestRow[] { new TestRow(1), new TestRow(2), new TestRow(3) };
grid.AutoGenerateColumns = false;
for (int i = 0; i < data[0].Values.Length; i++)
{
    var col = new DataGridCheckBoxColumn();
    //Here i bind to the various indices.
    var binding = new Binding("Values[" + i + "]");
    col.Binding = binding;
    grid.Columns.Add(col);
}
grid.ItemsSource = data;

What that looks like (lacks headers and everything of course)

---

Edit: To make the above code cleaner you should expose a static property in your items-class which is used uniformly when creating the arrays, using data[0].Values.Length when creating the columns could obviously throw an exception if the data collection is empty.

Inconsolable

Outch, so the binding syntax allows me to specify an array index in a plain C#-like syntax. While googling I came across some other post saying it would be nice if WPF could bind to an array index and thus didn't even try the most obvious thing! – Photosynthesis

Thanks by the way for the style tips and verbose answer (with screenshot!). I have already written my share of code over the years, but I guess I'd better not complain after posting a code snippet containing an unrolled array :o) – Photosynthesis