Update Readme file (new template)

Author: sergepilipchuk

Images/expanded-rows.jpg

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-*Files to look at*:
 
-* [GroupChildSelector.cs](./CS/GridGroupSelect/GroupChildSelector.cs) (VB: [GroupChildSelector.vb](./VB/GridGroupSelect/GroupChildSelector.vb))
+# WPF Data Grid – Select Child Rows When a User Clicks or Expands a Group Row
+
+This example selects all child rows in a group when a user expands a group row or clicks a group row.
+
+![Select Child Rows When a User Clicks or Expands a Group Row](./Images/expanded-rows.jpg)
+
+Use this technique when you need to:
+
+* Select all children after a group expands.
+* Select children on a group-row click.
+* Apply recursive selection in nested groups.
+
+## Implementation Details
+
+### Attached Behavior
+
+Specify the `GroupChildSelector.Mode` attached property for the [`TableView`](https://docs.devexpress.com/WPF/DevExpress.Xpf.Grid.TableView) and set the property to one of the following modes:
+
+* `None` — no selection.
+* `Child` — select direct children.
+* `Hierarchical` — select all descendants in expanded subgroups.
+
+The child-row selection logic works with two events: 
+
+* `PreviewMouseLeftButtonUp` - fires when a user clicks a group row. 
+* [`GroupRowExpanding`](https://docs.devexpress.com/WPF/DevExpress.Xpf.Grid.GridControl.GroupRowExpanding) - fires when a user expands a group. 
+
+When either event occurs, the child-row selection logic selects all child rows in that group and calls [`BeginSelection`](https://docs.devexpress.com/WPF/DevExpress.Xpf.Grid.DataControlBase.BeginSelection) and [`EndSelection`](https://docs.devexpress.com/WPF/DevExpress.Xpf.Grid.DataControlBase.EndSelection) methods to apply the changes in one step.
+
+```xaml
+<dxg:GridControl>
+  <dxg:GridControl.View>
+    <dxg:TableView
+      local:GroupChildSelector.Mode="Hierarchical" />
+  </dxg:GridControl.View>
+</dxg:GridControl>
+```
+
+### Selection Logic
+
+The `GroupChildSelector` calls the `SelectChild(grid, groupRowHandle)` method to select all child rows in a group. In `Hierarchical` mode, if a child row is an expanded group, the method calls itself to select that group’s child rows. The code calls the `BeginSelection` method before changes and the `EndSelection` method after changes to update the selection in a single step.
+
+### Data Setup
+
+In the `MainWindow` constructor, the `DataContext` is set to the collection returned by the `SampleDataRow.CreateRows()` method. This method creates 100 data rows with `Id`, `Group`, `Name`, and `HasFlag` fields.
+
+## Files to Review
+
 * [MainWindow.xaml](./CS/GridGroupSelect/MainWindow.xaml) (VB: [MainWindow.xaml](./VB/GridGroupSelect/MainWindow.xaml))
 * [MainWindow.xaml.cs](./CS/GridGroupSelect/MainWindow.xaml.cs) (VB: [MainWindow.xaml.vb](./VB/GridGroupSelect/MainWindow.xaml.vb))
+* [GroupChildSelector.cs](./CS/GridGroupSelect/GroupChildSelector.cs) (VB: [GroupChildSelector.vb](./VB/GridGroupSelect/GroupChildSelector.vb))
 * [SampleDataRow.cs](./CS/GridGroupSelect/SampleDataRow.cs) (VB: [SampleDataRow.vb](./VB/GridGroupSelect/SampleDataRow.vb))
-<!-- default file list end -->
-# WPF Grid - Select child rows when a user clicks or expands a group row
 
+## Documentation
 
-<p>This example demonstrates how to select all child rows in a group when a group row is expanded or clicked.</p>
+* [Data Grid](https://docs.devexpress.com/WPF/6084/controls-and-libraries/data-grid)
+* [GridControl](https://docs.devexpress.com/WPF/DevExpress.Xpf.Grid.GridControl)
+* [GridColumn](https://docs.devexpress.com/WPF/DevExpress.Xpf.Grid.BandBase.GridColumn)
+* [TableView](https://docs.devexpress.com/WPF/DevExpress.Xpf.Grid.TableView)
 
-<br/>
+## More Examples
 
+* [WPF Data Grid - Specify Custom Content for Headers Displayed in the Column Chooser](https://github.com/DevExpress-Examples/wpf-data-grid-custom-content-for-column-chooser-headers)
+* [WPF Data Grid - Bind to Dynamic Data](https://github.com/DevExpress-Examples/wpf-bind-gridcontrol-to-dynamic-data)
+* [Implement CRUD Operations in the WPF Data Grid](https://github.com/DevExpress-Examples/wpf-data-grid-implement-crud-operations)
+* [WPF Grid - Resize Rows Using a Splitter](https://github.com/sergepilipchuk/wpf-grid-resize-rows-using-splitter)
 
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