# Drag and Drop using RadDragDropService

This article will guide you through the process of achieving drag and drop functionality from **RadListView** to **RadGridView** and vice versa. For this purpose, we will use the **RadDragDropService**, supported by both of the controls. Let’s assume that the **RadListView**  is in unbound mode and the **ViewType** property is set to *DetailsView*. The **RadGridView** is bound to a DataTable with identical columns as the manually added ones to the **RadListView**.

#### Populating with data

```C#
DataTable gridViewDataTable = new DataTable();

public DragDropRadDragDropService()
{
    InitializeComponent();
    
    this.radListView1.Columns.Add("Id");
    this.radListView1.Columns.Add("Title");
    this.radListView1.ViewType = Telerik.WinControls.UI.ListViewType.DetailsView;
    
    List<string> products = new List<string>()
    {
        "Telerik UI for WinForms",
        "Telerik UI for Silverlight",
        "Telerik UI for WPF",
        "Telerik UI for ASP.NET AJAX"
    };
    for (int i = 0; i < products.Count; i++)
    {
        ListViewDataItem item = new ListViewDataItem();
        this.radListView1.Items.Add(item);
        item["Id"] = Guid.NewGuid().ToString();
        item["Title"] = products[i];
    }
    
    gridViewDataTable.Columns.Add("Id", typeof(string));
    gridViewDataTable.Columns.Add("Title", typeof(string));
    gridViewDataTable.Rows.Add(Guid.NewGuid().ToString(), "Kendo UI");
    gridViewDataTable.Rows.Add(Guid.NewGuid().ToString(), "Telerik UI for iOS");
    gridViewDataTable.Rows.Add(Guid.NewGuid().ToString(), "Telerik UI for Android");
    gridViewDataTable.Rows.Add(Guid.NewGuid().ToString(), "Telerik UI for Windows Phone");
    this.radGridView1.DataSource = gridViewDataTable;
}

```

```VB.NET
Private gridViewDataTable As New DataTable()
Sub New()

    InitializeComponent()
    Me.RadListView1.Columns.Add("Id")
    Me.RadListView1.Columns.Add("Title")
    Me.RadListView1.ViewType = Telerik.WinControls.UI.ListViewType.DetailsView

    Dim products As New List(Of String)() From { _
        "Telerik UI for WinForms", _
        "Telerik UI for Silverlight", _
        "Telerik UI for WPF", _
        "Telerik UI for ASP.NET AJAX" _
    }
    For i As Integer = 0 To products.Count - 1
        Dim item As New ListViewDataItem()
        Me.RadListView1.Items.Add(item)
        item("Id") = Guid.NewGuid().ToString()
        item("Title") = products(i)
    Next

    gridViewDataTable.Columns.Add("Id", GetType(String))
    gridViewDataTable.Columns.Add("Title", GetType(String))
    gridViewDataTable.Rows.Add(Guid.NewGuid().ToString(), "Kendo UI")
    gridViewDataTable.Rows.Add(Guid.NewGuid().ToString(), "Telerik UI for iOS")
    gridViewDataTable.Rows.Add(Guid.NewGuid().ToString(), "Telerik UI for Android")
    gridViewDataTable.Rows.Add(Guid.NewGuid().ToString(), "Telerik UI for Windows Phone")
    Me.RadGridView1.DataSource = gridViewDataTable
End Sub
```

## Drag and Drop from RadGridView to RadListView

> caption Figure 1: Drag and Drop from RadGridView to RadListView

![WinForms RadListView Drag and Drop from RadGridView to RadListView](https://www.telerik.com/products/winforms/documentation/assets/f81bd3a4f6391fa3c6676348606f4781/listview-drag-and-drop-drag-and-drop-using-raddragdropservice001.gif)

1\. The first thing we need to do is to start the **RadGridView**’s drag and drop service when a user clicks on a row with the left mouse down. For this purpose, we should create a custom [grid behavior](https://www.telerik.com/products/winforms/documentation/controls/gridview/visual-elements/rows/row-behaviors):

#### Starting a drag and drop operation

```C#
//initiates drag and drop service for clicked rows
public class CustomRowGridBehavior : GridDataRowBehavior
{
    protected override bool OnMouseDownLeft(MouseEventArgs e)
    {
        GridDataRowElement row = this.GetRowAtPoint(e.Location) as GridDataRowElement;
        if (row != null)
        {
            RadGridViewDragDropService svc = this.GridViewElement.GetService<RadGridViewDragDropService>();
            svc.Start(row);
        }
        return base.OnMouseDownLeft(e);
    }
}

```

```VB.NET
'initiates drag and drop service for clicked rows

Public Class CustomRowGridBehavior
    Inherits GridDataRowBehavior
    Protected Overrides Function OnMouseDownLeft(e As MouseEventArgs) As Boolean
        Dim row As GridDataRowElement = TryCast(Me.GetRowAtPoint(e.Location), GridDataRowElement)
        If row IsNot Nothing Then
            Dim svc As RadGridViewDragDropService = Me.GridViewElement.GetService(Of RadGridViewDragDropService)()
            svc.Start(row)
        End If
        Return MyBase.OnMouseDownLeft(e)
    End Function
End Class

```

2\. Next, we should register this behavior in our grid:

#### Register the custom row behavior

```C#
//register the custom row behavior
BaseGridBehavior gridBehavior = this.radGridView1.GridBehavior as BaseGridBehavior;
gridBehavior.UnregisterBehavior(typeof(GridViewDataRowInfo));
gridBehavior.RegisterBehavior(typeof(GridViewDataRowInfo), new CustomRowGridBehavior());

```

```VB.NET
'register the custom row behavior
Dim gridBehavior As BaseGridBehavior = TryCast(Me.RadGridView1.GridBehavior, BaseGridBehavior)
gridBehavior.UnregisterBehavior(GetType(GridViewDataRowInfo))
gridBehavior.RegisterBehavior(GetType(GridViewDataRowInfo), New CustomRowGridBehavior())

```

3\. It is necessary to subscribe to the **PreviewDragStart**, **PreviewDragOver** and **PreviewDragDrop** events of the grid’s **RadDragDropService**. The **PreviewDragStart** event is fired once the drag and drop service on the grid is started. We should notify the service that the drag and drop operation can move forward. In the **PreviewDragOver**  event you can control on what targets to allow dropping the dragged row. The **PreviewDragDrop** event performs the actual move of the row from the **RadGridView** to the **RadListView**.

#### Handling the RadDragDropService's events

```C#
private void svc_PreviewDragStart(object sender, PreviewDragStartEventArgs e)
{
    e.CanStart = true;
}

private void svc_PreviewDragOver(object sender, RadDragOverEventArgs e)
{
    if (e.DragInstance is GridDataRowElement)
    {
        e.CanDrop = e.HitTarget is DetailListViewDataCellElement ||
                    e.HitTarget is DetailListViewElement;
    }
}

private void svc_PreviewDragDrop(object sender, RadDropEventArgs e)
{
    DetailListViewDataCellElement targetCell = e.HitTarget as DetailListViewDataCellElement;
    DetailListViewElement targetElement = e.HitTarget as DetailListViewElement;
    GridDataRowElement draggedRow = e.DragInstance as GridDataRowElement;
    
    if (draggedRow == null)
    {
        return;
    }
    ListViewDataItem item = new ListViewDataItem();            
    DataRow draggedDataBoundItem = ((DataRowView)draggedRow.RowInfo.DataBoundItem).Row;
    if (targetElement != null)
    {
        ((RadListViewElement)targetElement.Parent).Items.Add(item) ;
    }
    if (targetCell != null)
    {
        BaseListViewVisualItem targetVisualItem = targetCell.RowElement;
        
        int insertIndex = targetCell.Row.ListView.Items.IndexOf(targetVisualItem.Data);
        if (insertIndex > -1)
        {
            targetCell.Row.ListView.Items.Insert(insertIndex, item);
        }
    }
    item["Id"] = draggedDataBoundItem["Id"];
    item["Title"] = draggedDataBoundItem["Title"];
    
    gridViewDataTable.Rows.Remove(draggedDataBoundItem);
}

```

```VB.NET
Private Sub svc_PreviewDragStart(sender As Object, e As PreviewDragStartEventArgs)
    e.CanStart = True
End Sub

Private Sub svc_PreviewDragOver(sender As Object, e As RadDragOverEventArgs)
    If TypeOf e.DragInstance Is GridDataRowElement Then
        e.CanDrop = TypeOf e.HitTarget Is DetailListViewDataCellElement OrElse TypeOf e.HitTarget Is DetailListViewElement
    End If
End Sub

Private Sub svc_PreviewDragDrop(sender As Object, e As RadDropEventArgs)
    Dim targetCell As DetailListViewDataCellElement = TryCast(e.HitTarget, DetailListViewDataCellElement)
    Dim targetElement As DetailListViewElement = TryCast(e.HitTarget, DetailListViewElement)
    Dim draggedRow As GridDataRowElement = TryCast(e.DragInstance, GridDataRowElement)

    If draggedRow Is Nothing Then
        Return
    End If
    Dim item As New ListViewDataItem()
    Dim draggedDataBoundItem As DataRow = DirectCast(draggedRow.RowInfo.DataBoundItem, DataRowView).Row
    If targetElement IsNot Nothing Then
        DirectCast(targetElement.Parent, RadListViewElement).Items.Add(item)
    End If
    If targetCell IsNot Nothing Then
        Dim targetVisualItem As BaseListViewVisualItem = targetCell.RowElement

        Dim insertIndex As Integer = targetCell.Row.ListView.Items.IndexOf(targetVisualItem.Data)
        If insertIndex > -1 Then
            targetCell.Row.ListView.Items.Insert(insertIndex, item)
        End If
    End If
    item("Id") = draggedDataBoundItem("Id")
    item("Title") = draggedDataBoundItem("Title")

    gridViewDataTable.Rows.Remove(draggedDataBoundItem)
End Sub

```

## Drag and Drop from RadListView to RadGridView

> caption Figure 2: Drag and Drop from RadListView to RadGridView

![WinForms RadListView Drag and Drop from RadListView to RadGridView](https://www.telerik.com/products/winforms/documentation/assets/b58d982e06d3d649aae6aad469f5681b/listview-drag-and-drop-drag-and-drop-using-raddragdropservice002.gif)

1\. In order to enable dragging an item from the **RadListView** and dropping it onto the **RadGridView**, it is necessary to set the RadListView.**AllowDragDrop** property to *true*.

#### Subscribing to the RadDragDropService's events

```C#
this.radListView1.ListViewElement.DragDropService.PreviewDragOver += DragDropService_PreviewDragOver;
this.radListView1.ListViewElement.DragDropService.PreviewDragDrop += DragDropService_PreviewDragDrop;
    
```

```VB.NET
AddHandler Me.RadListView1.ListViewElement.DragDropService.PreviewDragOver, AddressOf DragDropService_PreviewDragOver
AddHandler Me.RadListView1.ListViewElement.DragDropService.PreviewDragDrop, AddressOf DragDropService_PreviewDragDrop

```

2\. To implement drag and drop functionality for this scenario, we will use the ListViewElement.**DragDropService**, which is a derivative of the **RadDragDropService** . Subscribe to its **PreviewDragOver**  and **PreviewDragDrop** events. In the **PreviewDragOver** event allow dropping over a row element or over the table element. The **PreviewDragDrop** event performs the actual inserting of the dragged item into the **RadGridView**’s data source:

#### Handling the RadDragDropService's events

```C#
private void DragDropService_PreviewDragOver(object sender, RadDragOverEventArgs e)
{
    e.CanDrop = e.HitTarget is GridTableElement ||
                e.HitTarget is GridDataRowElement;
}

private void DragDropService_PreviewDragDrop(object sender, RadDropEventArgs e)
{
    BaseListViewVisualItem draggedItem = e.DragInstance as BaseListViewVisualItem;
    GridDataRowElement rowElement = e.HitTarget as GridDataRowElement;
    GridTableElement tableElement = e.HitTarget as GridTableElement;
    
    if (rowElement == null && tableElement == null)
    {
        return;
    }
    e.Handled = true;           
    DataRow newRow = gridViewDataTable.NewRow();
    if (tableElement != null)
    {
        gridViewDataTable.Rows.Add(newRow);
    }
    if (rowElement != null)
    {
        GridViewRowInfo targetRow = rowElement.RowInfo;
        
        int insertIndex = this.radGridView1.Rows.IndexOf(targetRow);
        if (insertIndex > -1)
        {
            gridViewDataTable.Rows.InsertAt(newRow, insertIndex);
        }
    }
    newRow["Id"] = draggedItem.Data["Id"];
    newRow["Title"] = draggedItem.Data["Title"];
    
    this.radListView1.Items.Remove(draggedItem.Data);
}

```

```VB.NET
Private Sub DragDropService_PreviewDragOver(sender As Object, e As RadDragOverEventArgs)
    e.CanDrop = TypeOf e.HitTarget Is GridTableElement OrElse TypeOf e.HitTarget Is GridDataRowElement
End Sub

Private Sub DragDropService_PreviewDragDrop(sender As Object, e As RadDropEventArgs)
    Dim draggedItem As BaseListViewVisualItem = TryCast(e.DragInstance, BaseListViewVisualItem)
    Dim rowElement As GridDataRowElement = TryCast(e.HitTarget, GridDataRowElement)
    Dim tableElement As GridTableElement = TryCast(e.HitTarget, GridTableElement)

    If rowElement Is Nothing AndAlso tableElement Is Nothing Then
        Return
    End If
    e.Handled = True
    Dim newRow As DataRow = gridViewDataTable.NewRow()
    If tableElement IsNot Nothing Then
        gridViewDataTable.Rows.Add(newRow)
    End If
    If rowElement IsNot Nothing Then
        Dim targetRow As GridViewRowInfo = rowElement.RowInfo

        Dim insertIndex As Integer = Me.RadGridView1.Rows.IndexOf(targetRow)
        If insertIndex > -1 Then
            gridViewDataTable.Rows.InsertAt(newRow, insertIndex)
        End If
    End If
    newRow("Id") = draggedItem.Data("Id")
    newRow("Title") = draggedItem.Data("Title")

    Me.RadListView1.Items.Remove(draggedItem.Data)
End Sub

```

## See Also

* [Drag and Drop in bound mode](https://www.telerik.com/products/winforms/documentation/controls/listview/drag-and-drop/drag-and-drop-in-bound-mode)
* [Drag and Drop from another control](https://www.telerik.com/products/winforms/documentation/controls/listview/drag-and-drop/drag-and-drop-from-another-control)
* [Combining RadDragDropService and OLE drag-and-drop](https://www.telerik.com/products/winforms/documentation/controls/listview/drag-and-drop/combining-raddragdropservice-and-ole-drag-and-drop)