MainWindow.xaml

<Window x:Class="How_to_Drag_and_Drop_Between_GridControls.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="500" Width="950">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition></ColumnDefinition>
            <ColumnDefinition></ColumnDefinition>
        </Grid.ColumnDefinitions>

        <dxg:GridControl Name="gridControl1" AutoGenerateColumns="AddNew" EnableSmartColumnsGeneration="True">
            <dxg:GridControl.View>
                <dxg:TreeListView KeyFieldName="ID" 
                                  ParentFieldName="ParentID" 
                                  AutoExpandAllNodes="True"
                                  AutoWidth="True" 
                                  AllowDragDrop="True" 
                                  DragRecordOver="OnDragRecordOver"/>
            </dxg:GridControl.View>
        </dxg:GridControl>

        <dxg:GridControl Name="gridControl2" Grid.Column="1" AutoGenerateColumns="AddNew" EnableSmartColumnsGeneration="True">
            <dxg:GridControl.View>
                <dxg:CardView AllowDragDrop="True" 
                              DragRecordOver="OnDragRecordOver"/>
            </dxg:GridControl.View>
        </dxg:GridControl>
    </Grid>
</Window>