How to set a DataTemplate for a column that is bound to System.Double Property?

[Kornelije]

I have a very specific problem, so please try to understand the issues it relates to.

I am logging activities for users accross dates.
An activity can be authorized and has a related value.

Take a look at this table:

        Mark        Jack        Kirk
1/1/2012    12 (A)      11 (A)
1/2/2012    18          15          4 (A)
1/3/2012    8 (A)       6 (A)       4

That means that on the the 3rd of January, Mark was active with a value of 8 and authorized, while Kirk was active with a value of 4, not authorized. On Jan 1, Kirk was not active at all. I hope the table makes sense.

The underlying data looks like this.

public class Activity
{
    public String User { get; set; }

    public DateTime Time { get; set; }
    public Double? Value { get; set; }

    public Boolean IsAuthorized { get; set; }
}

Therefore, there is an instance of the Activity for each Time-User pair.

Now, I am trying to show this data in a RadGridView with three specific and mandatory requirements:

1) The number of users must remain variable. In other words, I don't know exactly how many columns will I need at compile time.

2) I must be able to set a different background color for cells that are not authorized (IsAuthorized == false). I don't want to display (A) in results, that's only indicative for this example. I want the background color changed appropriately instead.

3) Data must be sortable by all columns, both by time and by any of the user column.sortable

I've tried to create a class that represents a Grid row, that has a dynamic number of values, something like this:

public class ActivitiesDataRow
{
    public DateTime TimeStamp { get; set; }

    public List<string> ColumnHeaders { get; set; }
    public List<double?> Values { get; set; }
}

Then I create rows from all the activities. I turn off the auto-generation of columns, and make them manually, setting them like this:

List<Activity> activities = new List<Activity>();
List<ActivitiesDataRow> activityRows = new List<ActivitiesDataRow>();

// ...
// ...

List<String> users = activities.Select(a => a.User).Distinct().ToList();

for (int i = 0; i < numberOfUsers; i++)
{
    GridViewDataColumn col = new GridViewDataColumn();

    // Get the names of the users, they are in the same order as
    // their values in ActivitiesDataRow
    col.Header = userNames[i];

    col.DataType = typeof(ActivitiesDataRow);
    Binding bnd = new Binding("Values");
    bnd.Converter = new ActivityDataRowCollectionConverter();
    bnd.ConverterParameter = i;
    col.DataMemberBinding = bnd;
    gridView.Columns.Add(col);
}

public class ActivityDataRowCollectionConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        // Since "Values" property is bound, the value is the List<Double?>
        return (value as List<Double?>)[(int)parameter];
    }
}

How can I make it so that background color is set depending on the IsAuthorized value?

If it can't be done by using this approach (List<Double?> + ValueConverter), what changes would I have to do to be able to satisfy all three requirements?

(I've seen the Telerik's video example that shows how to style the cell by using a DataTemplate and StyleSelectors, but it was binding to a known double property in DataTemplate. I don't have a known property that represents the value, but a list of them.)

[Kornelije]

I have change my question during writing but forgot to update the title, so it may be misleading. Unfortunately, I am unable to edit the post to change the title. My apologies.

[Nedyalko Nikolov]

Hi,

Am I missing something? You want to change the background of a double value cell depending on "IsAuthorized" property not the double property. So I think that you can do that with a StyleSelector. Keep in mind that you have a reference to the whole object not only value of the cell, so you can use any property of your data object. You can take a look at this online help topic as well.
Let me know if this does not help.

Regards,
Nedyalko Nikolov
the Telerik team