WPF DataGrid组合框更改选择问题

Question

I have a DataGrid with one column that has a ComboBox in it:

    DataGridTemplateColumn colDataType = new DataGridTemplateColumn();
    colDataType.Header = "Type";
    var cboFactoryDT = new FrameworkElementFactory(typeof(ComboBox));
    cboFactoryDT.SetValue(ComboBox.ItemsSourceProperty, Enum.GetValues(typeof(BuilderDataTypes)).Cast<BuilderDataTypes>());
    b = new Binding("Value[1]");
    b.Converter = new ObjectToDataTypeConverter();
    b.UpdateSourceTrigger = UpdateSourceTrigger.LostFocus;
    b.Mode = BindingMode.TwoWay;
    cboFactoryDT.SetBinding(ComboBox.SelectedIndexProperty, b);
    cboFactoryDT.SetValue(ComboBox.IsSynchronizedWithCurrentItemProperty, true);
    DataTemplate dtDT = new DataTemplate { VisualTree = cboFactoryDT };
    colDataType.CellTemplate = dtDT;

And my Converter class is:

public class ObjectToDataTypeConverter : IValueConverter
{
    public object Convert(object value, Type targetType,
        object parameter, CultureInfo culture)
    {
        try
        {
            return int.Parse(value.ToString());
        }
        catch { return 0; }
    }

    public object ConvertBack(object value, Type targetType,
        object parameter, CultureInfo culture)
    {
        try
        {
            return value;
        }
        catch { return 0; }
    }
}

Now, the problem is when I change the selection in one of the rows, all the comboboxes in all the rows are changed to the same selection as well.

What could be the problem?

Answer 1

Seeing exception handling like yours is a pet-pevee of mine. Your code has the abiltiy to swallow Fatal Exceptions, wich is a deadly sin of Exception handling. You should read these articles on proper exception handling:

http://blogs.msdn.com/b/ericlippert/archive/2008/09/10/vexing-exceptions.aspx http://www.codeproject.com/Articles/9538/Exception-Handling-Best-Practices-in-NET

What wonders me even more, is that you do that faulty handling to Parse. If you do not want the Vexing Exceptions, there is TryParse just for that. The only reason to not use it, is if you somehow are below Framework Version 2.0, where it was introduced. I have repalcement code for that case, but with WPF that seems unlikely.