Alex,

I tried your way but seems like it doesn't work...I attached my codes. can u pls take a look.

Thanks a lot.   

<igDP:XamDataGrid Grid.Row="1"
                        x:Name="xamDataGrid"
                        Theme="Aero"
                        AutoFit="False"
                        ContextMenu="{x:Null}"
                        SnapsToDevicePixels="True"
                        ScrollingMode="Immediate"
                        AllowDrop="True"
                        RecordContainerGenerationMode="Recycle"
                        CellContainerGenerationMode="Recycle"
                                RecordLoadMode="LoadOnDemand"
                        Background="Gray"
                       
                        DragOver="OnDragOver"
                        Drop="OnDataDrop"
                        PreviewMouseDown="OnXamDataGridPreviewMouseDown"
                        PreviewMouseMove="OnXamDataGridPreviewMouseMove"
                        PreviewMouseUp="OnXamDataGridPreviewMouseUp"
                        MouseDoubleClick="OnGridMouseDoubleClick"
                        MouseRightButtonDown="OnGridMouseRightButtonDown"
                        IsGroupByAreaExpanded="False">

        <igDP:XamDataGrid.Resources>
          <Style TargetType="{x:Type igDP:RecordSelector}">
            <Setter Property="Template">
              <Setter.Value>
                <ControlTemplate TargetType="{x:Type igDP:RecordSelector}">
                  <CheckBox
                    HorizontalAlignment="Center"
                    VerticalAlignment="Center"
                    IsChecked="{Binding Path=DataItem.IsChecked}"
                    Checked="OnChecked"
                    Unchecked="OnUnChecked"
                  >
                  </CheckBox>
                </ControlTemplate>
              </Setter.Value>
            </Setter>
          </Style>
          <Style TargetType="{x:Type igDP:DataRecordPresenter}">
            <Setter Property="Margin" Value="80,0,0,0"/>
          </Style>
        </igDP:XamDataGrid.Resources>
       
        <igDP:XamDataGrid.FieldLayoutSettings>
          <igDP:FieldLayoutSettings
                  DataRecordSizingMode="SizedToContentAndIndividuallySizable"
                  AutoGenerateFields="True"
                  RecordSelectorLocation="LeftOfCellArea"
                  ResizingMode="Default"
                 
                  SelectionTypeRecord="Extended"
                  SelectionTypeField="Extended"
                  DataRecordPresenterStyle="{StaticResource headerStyle}"
                  DataRecordCellAreaStyle="{StaticResource rowStyle}"
                  SelectionTypeCell="Extended"/>
        </igDP:XamDataGrid.FieldLayoutSettings>
        <igDP:XamDataGrid.FieldSettings>
          <igDP:FieldSettings
                      AllowEdit="False"
                      CellClickAction="SelectRecord"
                      CellMinWidth="0"
                      AllowCellVirtualization="true"
                      CellValuePresenterStyle="{StaticResource cellStyle}"
                      LabelPresenterStyle="{StaticResource columnStyle}"/>
          <!--CellValuePresenterStyle="{StaticResource cellStyle}"-->
        </igDP:XamDataGrid.FieldSettings>
      </igDP:XamDataGrid>

Alex,

Actually I meant (0,0,20,0) not (0,20,0,0). Sorry about confusing.

About your way (decrease the first column of child row) which point can I do this? I mean in XMAL or code-behide? If Code-behide any event-handler you suggest?

Many Thanks

If you will not be changing this cell's width, you can set it in the XAML. If you need to change it in runtime, you can use InitializeRecord event.

Alex.

I wrote handler as below...But it doesn't work...any idea?

Thanks

        void OnInitializeRecord(object sender, Infragistics.Windows.DataPresenter.Events.InitializeRecordEventArgs e)
        {
            DataRecord dr = e.Record as DataRecord;

            if (dr != null && dr.ParentRecord != null)
                dr.Cells[0].Field.Settings.LabelWidth = dr.Cells[0].Field.Settings.LabelWidth - 20;

        }

also tried cellwidth...no luck...guess the way i set width of cell is wrong?

Try changing both like CellWidht and LabelWidth

Note: make sure you have defined the fields and CellWidth and LabelWidth in the xaml, otherwise these numbers will be NaN and nothing will happen.

Alex.