Silverlight DataGrid Combobox Newbie Question

Question

Good Day,

I am working on a datagrid in silverlight. I have a WCF service that returns a List that works fine when I populate a datagrid. CoreEmployee returns properties of EmployeeId, FirstName, LastName, HourlyRate, HireDate. This is my XAML of the hourly rate:

<data:DataGridTemplateColumn Header="Hourly Rate">
    <data:DataGridTemplateColumn.CellTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding HourlyRate}" />
        </DataTemplate>
    </data:DataGridTemplateColumn.CellTemplate>
    <data:DataGridTemplateColumn.CellEditingTemplate>
        <DataTemplate>
            <!--ItemsSource="{Binding PayRateList, Source={StaticResource PayRateProvider}}"-->
            <ComboBox SelectedItem="{Binding HourlyRate}" 
                      ItemsSource="{Binding HourlyRates}"
                      local:ComboBoxService.ForceOpen="true"
                  />
        </DataTemplate>
    </data:DataGridTemplateColumn.CellEditingTemplate>
</data:DataGridTemplateColumn>

Here is what I am trying to accomplish: When the hourly rates for each employee is populated on the data grid, I also want a list of all the unique salary rates for each person in the data grid.

My code behind does do that:

private List<Decimal> _hourlyRates = new List<decimal>();
public List<Decimal> HourlyRates
{
    get { return _hourlyRates; }
}

void client_GetEmployeesCompleted(object sender, GetEmployeesCompletedEventArgs e)
{
    try
    {
        if (e.Result != null)
        {
            EmployeesGrid.ItemsSource = e.Result;

            // Convert an ObservableCollection<T> to a List<T>
            List<CoreEmployee> employees = e.Result.ToList<CoreEmployee>();

            // Generate a unique list
            // http://stackoverflow.com/questions/223400/checking-for-duplicates-in-a-complex-object-using-linq-or-lamda-expression
            var results = from item in employees
                          group item by item.HourlyRate into g
                          select g.First();

            foreach (CoreEmployee employee in results)
            {
                HourlyRates.Add(employee.HourlyRate);
            }

            _dataHasLoaded = true;
        }
    }
    catch (Exception exc)
    {
        // Eat the exception
    }
}

However, the problem occurs when I attempt to double click the textblock, the combo box does display, but without any data.

What am I doing wrong?

Answer 1

You should raise the PropertyChanged event on the HourlyRates property after populating the list in the foreach loop. Also, set the Mode of the ComboBox SelectedItem binding to TwoWay.