I am attempting similar fate, but not having 100% success. The data binding path works and i get the correct values in the converter (and send the correct back), however, I never see them assigned to the cells in my grid.

I've tried removing every editor and existing format possible to see if there is an over-ride somewhere. I've found none.

Please view my code and let me know if you see any issues.

Thanks - Glenn

The Style:

 <Style x:Key="compareRegMWValues" TargetType="{x:Type igDP:CellValuePresenter}">
                                    <Setter Property="Background">
                                        <Setter.Value>
                                            <MultiBinding Converter="{StaticResource CompareRegMWValues}">
                                                <Binding Path="Record.Cells[CurregMW].Value" RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type igDP:DataRecordPresenter}}"/>
                                                <Binding Path="Record.Cells[RegMW].Value" RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type igDP:DataRecordPresenter}}"/>
                                            </MultiBinding>
                                        </Setter.Value>
                                    </Setter>
                                </Style>

The Field:

 <igDP:Field Name="RegAssignDelta" Label="Reg Assign Delta">
                                            <igDP:Field.Settings>
                                                <igDP:FieldSettings AllowEdit="False"  CellWidth="70" LabelWidth="70"
                                                                    CellValuePresenterStyle="{StaticResource compareRegMWValues}"
                                                                    LabelPresenterStyle="{DynamicResource GridLabelPresenterStyle}"
                                                                    LabelTextAlignment="Center" AllowSummaries="True" SummaryUIType="MultiSelect">
                                                    <igDP:FieldSettings.EditorStyle>
                                                        <Style TargetType="{x:Type igEditors:XamNumericEditor}"  >
                                                            <Setter Property="Format" Value="######0.0"/>                                                           
                                                        </Style>
                                                    </igDP:FieldSettings.EditorStyle>
                                                </igDP:FieldSettings>
                                            </igDP:Field.Settings>
                                        </igDP:Field> 

The Converter:

 public object Convert(object[] values, Type targetType,object parameter, CultureInfo culture)
        {
            decimal value1 = 0;
            decimal value2 = 0;

            if (values[0] == null || values[1] == null) { return Binding.DoNothing; }               

             // If Current RegMW > Reg MW Then Blue
            value1 = System.Convert.ToDecimal(values[0]);
            value2 = System.Convert.ToDecimal(values[1]);

Yes using this solved the issue - Cells[Field1].Value . Thanks.

The issue here is in the binding path :

<Binding Path="DataItem.Value"/>
<Binding Path="Field1" />
<Binding Path="Field2" />

The DataRecord does not expose Field1 and Field2 public properties. What you could do is :

DataItem.Property1 and DataItem.Property2 

or

Cells[Field1].Value and Cells[Field2].Value

Thanks for the reply. I implemented this in the similar way. In the BrushConverter class I am not getting the Values I am looking for.

For each row the background of Field3 will be set depending on the values in Field1, 2 and 3. Can you help me figure out what I am doing wrong.

<Style x:Key="BackgroundColorConverter" TargetType="{x:Type igDP:CellValuePresenter}">
                            <Setter Property="Background">
                                <Setter.Value>
                                    <MultiBinding Converter="{StaticResource ColorConverter}">
                                        <Binding Path="DataItem.Value"/>
                                        <Binding Path="Field1" />
                                        <Binding Path="Field2" />
                                    </MultiBinding>
                               </Setter.Value>                               
                              
                            </Setter>
                        </Style>

<igDP:XamDataGrid.FieldLayouts>
                        <igDP:FieldLayout IsDefault="True">
                            <igDP:FieldLayout.Fields>
                                <igDP:Field Name="Field1" Label="Field1">
                                    <igDP:Field.Settings>
                                        <igDP:FieldSettings AllowEdit="False" CellHeight="30" />
                                    </igDP:Field.Settings>
                                </igDP:Field>
                                <igDP:Field Name="Field2" Label="Field2" >
                                    <igDP:Field.Settings>
                                        <igDP:FieldSettings AllowEdit="False" AllowGroupBy="True"/>
                                    </igDP:Field.Settings>
                                </igDP:Field>

                                <igDP:Field Name="Field3" Label="Field3">
                                    <igDP:Field.Settings>
                                        <igDP:FieldSettings AllowEdit="True" CellMaxWidth="150" CellValuePresenterStyle="{StaticResource BackgroundColorConverter}" />
                                    </igDP:Field.Settings>
                                </igDP:Field>

                               
                            </igDP:FieldLayout.Fields>
                        </igDP:FieldLayout>
                    </igDP:XamDataGrid.FieldLayouts>

public class BrushConvertor: IMultiValueConverter
    {
        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
        {
            int a =(int) values[0];
            int b =(int) values[1];
            int c =(int) values[2];
            if (a > (b-c))
            {
                return Brushes.Yellow;
            }
            else
            {
                return Brushes.Red;
            }
           
        }

        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }

    }