[DXCategory("DragDrop")]
public event DragDropEventHandler DragDrop

<DXCategory("DragDrop")>
Public Event DragDrop As DragDropEventHandler

using DevExpress.Utils.DragDrop;

//The code below assumes that you are moving data from a tree list to a grid.
//Create new grid rows, and populate them with data from tree list nodes.
private void dragDropEvents1_DragDrop(object sender, DragDropEventArgs e) {
    List<TreeListNode> list = e.Data as List<TreeListNode>;
    foreach (TreeListNode node in list) {
        gridView1.AddNewRow();
        gridView1.SetRowCellValue(GridControl.NewItemRowHandle, gridView1.Columns["DEPARTMENT"], node.GetValue(colDEPARTMENT1));
    }
    e.Handled = true;
}

Imports DevExpress.Utils.DragDrop

'The code below assumes that you are moving data from a tree list to a grid.
'Create new grid rows, and populate them with data from tree list nodes.
Private Sub dragDropEvents1_DragDrop(ByVal sender As Object, ByVal e As DevExpress.Utils.DragDrop.DragDropEventArgs) _
    Handles dragDropEvents1.DragDrop
    Dim list As List(Of TreeListNode) = TryCast(e.Data, List(Of TreeListNode))
    For Each node As TreeListNode In list
        gridView1.AddNewRow()
        gridView1.SetRowCellValue(GridControl.NewItemRowHandle, gridView1.Columns("DEPARTMENT"), node.GetValue(colDEPARTMENT1))
    Next node
    e.Handled = True
End Sub

using DevExpress.Utils.DragDrop;
using DevExpress.XtraGrid.Views.Grid;

dragDropEvents1.DragDrop += Behavior_DragDrop;

private void Behavior_DragDrop(object sender, DragDropEventArgs e) {
   DragDropGridEventArgs args = DragDropGridEventArgs.GetDragDropGridEventArgs(e);
   //You can also cast DragDropEventArgs to DragDropGridEventArgs.
   //DragDropGridEventArgs args = (DragDropGridEventArgs)e;
}

Imports DevExpress.Utils.DragDrop
Imports DevExpress.XtraGrid.Views.Grid

AddHandler DragDropEvents1.DragDrop, AddressOf Behavior_DragDrop
Private Sub Behavior_DragDrop(ByVal sender As Object, ByVal e As DragDropEventArgs)
   Dim args As DragDropGridEventArgs = DragDropGridEventArgs.GetDragDropGridEventArgs(e)
   'You can also cast DragDropEventArgs to DragDropGridEventArgs.
   'Dim args As DragDropGridEventArgs = CType(e, DragDropGridEventArgs)
End Sub

using DevExpress.Utils.DragDrop;
using DevExpress.XtraGrid.Views.Grid;

gridView1.OptionsBehavior.Editable = false;
gridView1.OptionsSelection.MultiSelect = true;
gridControl1.DataSource = CreateDataTable();
gridControl1.ViewRegistered += GridControl1_ViewRegistered;

private void dragDropEvents1_DragDrop(object sender, DragDropEventArgs e) {
    GridView masterView = e.Source as GridView;
    // Cast the event arguments to the DragDropGridEventArgs type
    // or call the static (Shared in VB) DragDropGridEventArgs.GetDragDropGridEventArgs method
    // to get grid-specific event arguments.
    DragDropGridEventArgs realArgs = (DragDropGridEventArgs)e;
    GridView sourceView = realArgs.Source as GridView;
    GridView targetView = realArgs.Target as GridView;

    var view1 = gridControl1.GetViewAt(gridControl1.PointToClient(e.Location));
    if(sourceView != null && targetView != null) {
        // Get the processed child row's parent ID.
        var newParentId = masterView.GetRowCellValue(targetView.SourceRowHandle, "Id");
        foreach(DataRowView dataRow in realArgs.DataRows) {
            // Update the processed child row's parent ID.
            dataRow.Row["ParentId"] = newParentId;
        }
        e.Handled = true;
    }
}

private void GridControl1_ViewRegistered(object sender, DevExpress.XtraGrid.ViewOperationEventArgs e) {
    if(e.View.IsDetailView) {
        // It is assumed that the Behavior Manager is placed
        // to the component tray in the Visual Studio Designer.
        behaviorManager1.Attach<DragDropBehavior>(e.View);
    }
}

public DataTable CreateDataTable() {
    masterTable = new DataTable();
    masterTable.Columns.Add("Id", typeof(int));
    masterTable.Columns.Add("Name");
    masterTable.Columns.Add("IsActive", typeof(bool));
    masterTable.Columns.Add("OrderCount", typeof(int));
    masterTable.Columns.Add("RegistrationDate", typeof(DateTime));

    for(int i = 0; i < 10; i++) {
        masterTable.Rows.Add(i, "Name" + i, i % 2 == 0, i * 10, DateTime.Now.AddDays(i));
    }

    DataTable childTable = new DataTable();
    childTable.Columns.Add("ParentId", typeof(int));
    childTable.Columns.Add("Id", typeof(int));
    childTable.Columns.Add("Name");

    for(int i = 0; i < 20; i++) {
        childTable.Rows.Add(i % 10, i, "Name" + i);
    }

    DataSet set = new DataSet();
    set.Tables.Add(masterTable);
    set.Tables.Add(childTable);
    set.Relations.Add(masterTable.Columns["Id"], childTable.Columns["ParentId"]);

    return masterTable;
}

Imports DevExpress.Utils.DragDrop
Imports DevExpress.XtraGrid.Views.Grid

gridView1.OptionsBehavior.Editable = False
gridView1.OptionsSelection.MultiSelect = True
gridControl1.DataSource = CreateDataTable()
AddHandler gridControl1.ViewRegistered, AddressOf GridControl1_ViewRegistered

Private Sub dragDropEvents1_DragDrop(ByVal sender As Object, ByVal e As DragDropEventArgs) Handles dragDropEvents1.DragDrop
    ' Cast the event arguments to the DragDropGridEventArgs type
    ' or call the static (Shared in VB) DragDropGridEventArgs.GetDragDropGridEventArgs method
    ' to get grid-specific event arguments.
    Dim masterView As GridView = TryCast(e.Source, GridView)
    Dim realArgs As DragDropGridEventArgs = CType(e, DragDropGridEventArgs)
    Dim sourceView As GridView = TryCast(realArgs.Source, GridView)
    Dim targetView As GridView = TryCast(realArgs.Target, GridView)

    Dim view1 = gridControl1.GetViewAt(gridControl1.PointToClient(e.Location))
    If sourceView IsNot Nothing AndAlso targetView IsNot Nothing Then
        ' Get the processed child row's parent ID.
        Dim newParentId = masterView.GetRowCellValue(targetView.SourceRowHandle, "Id")
        For Each dataRow As DataRowView In realArgs.DataRows
            ' Update the processed child row's parent ID.
            dataRow.Row("ParentId") = newParentId
        Next dataRow
        e.Handled = True
    End If
End Sub

Private Sub GridControl1_ViewRegistered(ByVal sender As Object, ByVal e As DevExpress.XtraGrid.ViewOperationEventArgs)
    If e.View.IsDetailView Then
        ' It is assumed that the Behavior Manager is placed
        ' to the component tray in the Visual Studio Designer.
        behaviorManager1.Attach(Of DragDropBehavior)(e.View)
    End If
End Sub

Public Function CreateDataTable() As DataTable
    masterTable = New DataTable()
    masterTable.Columns.Add("Id", GetType(Integer))
    masterTable.Columns.Add("Name")
    masterTable.Columns.Add("IsActive", GetType(Boolean))
    masterTable.Columns.Add("OrderCount", GetType(Integer))
    masterTable.Columns.Add("RegistrationDate", GetType(Date))
    For i As Integer = 0 To 9
        masterTable.Rows.Add(i, "Name" & i, i Mod 2 = 0, i * 10, Date.Now.AddDays(i))
    Next i

    Dim childTable As New DataTable()
    childTable.Columns.Add("ParentId", GetType(Integer))
    childTable.Columns.Add("Id", GetType(Integer))
    childTable.Columns.Add("Name")

    For i As Integer = 0 To 19
        childTable.Rows.Add(i Mod 10, i, "Name" & i)
    Next i

    Dim dataSet As New DataSet()
    dataSet.Tables.Add(masterTable)
    dataSet.Tables.Add(childTable)
    dataSet.Relations.Add(masterTable.Columns("Id"), childTable.Columns("ParentId"))

    Return masterTable
End Function

using DevExpress.Data.Filtering;
using DevExpress.Utils.DragDrop;
using DevExpress.Xpo;
using DevExpress.Xpo.DB;
using DevExpress.Xpo.Metadata;
using DevExpress.XtraGrid.Views.Grid;
using DevExpress.XtraTreeList;
using DevExpress.XtraTreeList.Nodes;

private UnitOfWork treeListSession = new UnitOfWork();
private UnitOfWork gridSession = new UnitOfWork();

XpoDefault.DataLayer = new SimpleDataLayer(new InMemoryDataStore());
XpoDefault.Session = null;
if (Convert.ToInt32(treeListSession.Evaluate<Customer>(new AggregateOperand(null, null, Aggregate.Count, null), null)) == 0) {
    for (int i = 0; i <= 9; i++)
        new Customer(treeListSession) { Name = string.Format("Name {0}", i) };
    treeListSession.CommitChanges();
}
if (Convert.ToInt32(gridSession.Evaluate<Customer>(new AggregateOperand(null, null, Aggregate.Count, null), null)) == 0) {
    for (int i = 0; i <= 9; i++)
        new Customer(treeListSession) { Name = string.Format("Name {0}", i) };
    gridSession.CommitChanges();
}

XPClassInfo treeClassInfo = treeListSession.Dictionary.GetClassInfo(typeof(Customer));
treeList1.DataSource = new XPCollection(treeListSession, treeClassInfo);            
XPClassInfo gridClassInfo = gridSession.Dictionary.GetClassInfo(typeof(Customer));
gridControl1.DataSource = new XPCollection(gridSession, gridClassInfo);

private void dragDropEvents1_DragOver(object sender, DragOverEventArgs e) {
    if (object.ReferenceEquals(e.Source, e.Target))
        return;
    e.Default();
    e.Action = DragDropActions.Move;
    e.Cursor = Cursors.Arrow;
}

private void dragDropEvents1_DragDrop(object sender, DragDropEventArgs e) {
    GridView view = e.Source as GridView;
    TreeList treeList = e.Target as TreeList;
    if (view != null && treeList != null) {
        int[] rowHandles = e.Data as int[];
        Customer customer = view.GetRow(rowHandles[0]) as Customer;

        XPCollection xpCollection = treeList.DataSource as XPCollection;

        Customer cloneCustomer = new Customer(treeListSession);
        cloneCustomer.Name = customer.Name;
        customer.Delete();
        treeListSession.CommitChanges();
        gridSession.CommitChanges();
        xpCollection.Add(cloneCustomer);

        TreeListHitInfo hitInfo = treeList.CalcHitInfo(treeList.PointToClient(e.Location));
        TreeListNode targetNode = hitInfo.Node;
        TreeListNode newNode = treeList.FindNodeByFieldValue("Oid", cloneCustomer.Oid);

        switch (e.InsertType) {
            case InsertType.None:
            case InsertType.AsChild:
            case InsertType.After:
            case InsertType.Before:
                treeList.MoveNode(newNode, newNode.ParentNode, false, treeList.Nodes.IndexOf(targetNode));
                break;
        }
    }
}

class Customer : XPObject {
    [Size(SizeAttribute.DefaultStringMappingFieldSize)]
    public string Name {
        get {
            return name;
        }
        set {
            SetPropertyValue("Name", ref name, value);
        }
    }

    private string name;

    public Customer(Session session) : base(session) {
    }
}

Imports DevExpress.Data.Filtering
Imports DevExpress.Utils.DragDrop
Imports DevExpress.Xpo
Imports DevExpress.Xpo.DB
Imports DevExpress.Xpo.Metadata
Imports DevExpress.XtraGrid.Views.Grid
Imports DevExpress.XtraTreeList
Imports DevExpress.XtraTreeList.Nodes

Private treeListSession As New UnitOfWork()
Private gridSession As New UnitOfWork()

XpoDefault.DataLayer = New SimpleDataLayer(New InMemoryDataStore())
XpoDefault.Session = Nothing
If Convert.ToInt32(treeListSession.Evaluate(Of Customer)(New AggregateOperand(Nothing, Nothing, Aggregate.Count, Nothing), Nothing)) = 0 Then
    For i As Integer = 0 To 9
        Dim tempVar = New Customer(treeListSession) With {.Name = String.Format("Name {0}", i)}
    Next i
    treeListSession.CommitChanges()
End If
If Convert.ToInt32(gridSession.Evaluate(Of Customer)(New AggregateOperand(Nothing, Nothing, Aggregate.Count, Nothing), Nothing)) = 0 Then
    For i As Integer = 0 To 9
        Dim tempVar = New Customer(treeListSession) With {.Name = String.Format("Name {0}", i)}
    Next i
    gridSession.CommitChanges()
End If

Dim treeClassInfo As XPClassInfo = treeListSession.Dictionary.GetClassInfo(GetType(Customer))
treeList1.DataSource = New XPCollection(treeListSession, treeClassInfo)
Dim gridClassInfo As XPClassInfo = gridSession.Dictionary.GetClassInfo(GetType(Customer))
gridControl1.DataSource = New XPCollection(gridSession, gridClassInfo)

Private Sub dragDropEvents1_DragOver(ByVal sender As Object, ByVal e As DragOverEventArgs) Handles dragDropEvents1.DragOver
    If Object.ReferenceEquals(e.Source, e.Target) Then
        Return
    End If
    e.Default()
    e.Action = DragDropActions.Move
    e.Cursor = Cursors.Arrow
End Sub

Private Sub dragDropEvents1_DragDrop(ByVal sender As Object, ByVal e As DragDropEventArgs) Handles dragDropEvents1.DragDrop
    Dim view As GridView = TryCast(e.Source, GridView)
    Dim treeList As TreeList = TryCast(e.Target, TreeList)
    If view IsNot Nothing AndAlso treeList IsNot Nothing Then
        Dim rowHandles() As Integer = TryCast(e.Data, Integer())
        Dim customer As Customer = TryCast(view.GetRow(rowHandles(0)), Customer)

        Dim xpCollection As XPCollection = TryCast(treeList.DataSource, XPCollection)

        Dim cloneCustomer As New Customer(treeListSession)
        cloneCustomer.Name = customer.Name
        customer.Delete()
        treeListSession.CommitChanges()
        gridSession.CommitChanges()
        xpCollection.Add(cloneCustomer)

        Dim hitInfo As TreeListHitInfo = treeList.CalcHitInfo(treeList.PointToClient(e.Location))
        Dim targetNode As TreeListNode = hitInfo.Node
        Dim newNode As TreeListNode = treeList.FindNodeByFieldValue("Oid", cloneCustomer.Oid)

        Select Case e.InsertType
            Case InsertType.None, InsertType.AsChild, InsertType.After, InsertType.Before
                treeList.MoveNode(newNode, newNode.ParentNode, False, treeList.Nodes.IndexOf(targetNode))
        End Select
    End If
End Sub

Public Class Customer
    Inherits XPObject

    <Size(SizeAttribute.DefaultStringMappingFieldSize)>
    Public Property Name() As String
        Get
            Return _Name
        End Get
        Set(ByVal value As String)
            SetPropertyValue("Name", _Name, value)
        End Set
    End Property

    Private _Name As String

    Public Sub New(ByVal session As Session)
        MyBase.New(session)
    End Sub
End Class