Question

first: we use infragistics xamdatagrid 11.1.20111.2053

our problem:

We use the grid with generic lists. So it’s very dynamic and must be prepared for any situation. We set for each field type theSortComparer, FilterComparer, the editor type, Edita type and style editor.
For some properties of a model, we use special TypeConverter.
For example, in a cell, some values ??can not be displayed.

0 = string.Empty
1 = 1
2 = 2

first solution, we only use the type converter and a special sort comparer:

public class HideZeroIntEntryConverter : Int32Converter
{
  public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) {
    if (value is int) {
      if (destinationType == typeof(string)) {
        return ((int)value != 0) ? value.ToString() : string.Empty;
      }
      return ((int)value != 0) ? value : Binding.DoNothing; // this is the best solution to tell the grid the cell is empty
    }
    return base.ConvertTo(context, culture, value, destinationType);
  }
}

this works perfect if we not decide to filter, but if we want to filter the values we see the ugly “Binding.DoNothing” in the filter drop down items (the sorting and filtering is also wrong).
also, we can not filter for “0” because we the converter says string.empty…

second solution, we use a special XamTextEditor:

public class HideZeroIntEntryTextEditor : XamTextEditor
{
  public HideZeroIntEntryTextEditor() {
    this.ValueToDisplayTextConverter = new HideZeroIntEntryValueConverter();
  }
}

public class HideZeroIntEntryValueConverter : IValueConverter
{
  public object Convert(object value, Type targetType, object parameter, CultureInfo culture) {
    if (value is int) {
      if (targetType == typeof(string)) {
        return ((int)value != 0) ? value.ToString() : string.Empty;
      }
      // this never happens
      return ((int)value != 0) ? value : Binding.DoNothing;
    }
    // this never happens
    return targetType == typeof(string) && value != null ? value.ToString() : value;
  }
}

and for the field settings

  field.Settings.EditAsType = typeof(int);

  field.Converter = null;
  field.Settings.EditorType = typeof(HideZeroIntEntryTextEditor);
  field.Settings.SortComparer = GenericComparer<int>.Instance;
  field.Settings.FilterComparer = GenericComparer<int>.Instance;
  field.Settings.GroupByComparer = GroupByRecordComparer<int>.Instance;

Now we can filter to “0”, even if this does not appear in the list.

But, in both cases, we can not filter by empty entries, because it actually does not exist!
We want to though!
In our opinion, this could be if we could make our own special filter. But this is unfortunately not so easy.
Yes, we can remove the special filter blanks and NonBlanks, BUT that applies to all grids.
A special filter to override is very complicated and does not even correct.

Ok, we want see empty cell, and want filter this cells, but the special filter doesn’t works correct!

What can we do, any ideas?

here is the question at infragistics

Answer 1

I answered this on the Infragistics forums right here with a sample.

You can use the RecordFilterDropDownPopulating event to remove the existing FilterDropDownItem for “(Blanks)” and replace it with a custom one for the value of 0 when the editor for the field is HideZeroIntEntryTextEditor. The following code accomplishes this:

void XamDataGrid1_RecordFilterDropDownPopulating(
  object sender, 
  //Infragistics.Windows.DataPresenter.Events.
  RecordFilterDropDownPopulatingEventArgs e) 
{
  if (e.Field.EditorTypeResolved == typeof(HideZeroIntEntryTextEditor)) {
    bool found = false;
    int index = 0;
    while (index < e.DropDownItems.Count && !found) {
      FilterDropDownItem item = e.DropDownItems[index];
      if (item.DisplayText == "(Blanks)") {
        e.DropDownItems.Remove(item);
        e.DropDownItems.Insert(index, new FilterDropDownItem(
          new ComparisonCondition(ComparisonOperator.Equals, 0), "(Blanks)"));
        found = true;
      }
      index++;
    }
  }
}