Hello mrth,

You may find the index of the record using the below line of code

((Infragistics.Windows.DataPresenter.Record)(values[0])).RecordManager.Sorted.IndexOf((DataRecord)values[0]);

I have created a sample for your requirement and below is the code snippet for your reference and attached is the sample.

<igDP:UnboundField Name="Details">       
                            <igDP:Field.Settings>
                                <igDP:FieldSettings>
                                    <igDP:FieldSettings.CellValuePresenterStyle>
                                        <Style TargetType="{x:Type igDP:CellValuePresenter}" >
                                            <Setter Property="Template">
                                                <Setter.Value>
                                                    <ControlTemplate  TargetType="{x:Type igDP:CellValuePresenter}">
                                                        <TextBlock TextAlignment="Right">
                                                            <TextBlock.Text>
                                                                <MultiBinding Converter="{StaticResource runTotal}">
                                                                    <Binding Path="Record" RelativeSource="{RelativeSource Mode=TemplatedParent}"/>
                                                                    <Binding Path="DataItem.CurrentDueAmount"/>
                                                                </MultiBinding>
                                                                </TextBlock.Text>
                                                        </TextBlock>
                                                    </ControlTemplate>
                                                </Setter.Value>
                                            </Setter>
                                        </Style>
                                    </igDP:FieldSettings.CellValuePresenterStyle>
                                </igDP:FieldSettings>
                            </igDP:Field.Settings>

                        </igDP:UnboundField>

 class RunTotalValue: IMultiValueConverter
    {
        #region IMultiValueConverter Members

        public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {               

            if(values != null && values[0] != null)
            {
                if(values[0] == DependencyProperty.UnsetValue || values[1] == DependencyProperty.UnsetValue)
                    return "";

                double currentValue = 0;
                double previousValue = 0;
                Double.TryParse(values[1].ToString(),out currentValue);
                int v_index =((Infragistics.Windows.DataPresenter.Record)(values[0])).RecordManager.Sorted.IndexOf((DataRecord)values[0]);
                if(v_index > 1)
                {
                    int newIndex = v_index - 1;
                    DataRecord v_previousRecord = (((Infragistics.Windows.DataPresenter.Record)(values[0])).RecordManager.Sorted)[newIndex];
                    Double.TryParse(v_previousRecord.Cells["CurrentDueAmount"].Value.ToString(), out previousValue);
                }
               
                double newValue = currentValue + previousValue;
                return newValue.ToString();
            }
            else
                return null;
        }

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

Please let me know if you have any questions on this matter.

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