First of all we have to create a windows forms application. For many elements it is possible to activate the drag&drop functionality in three steps:

- Set the 'AllowDrop' property to true
- Handle the 'DragEnter' event to change the cursor to a drag&drop symbol
- Handle the 'DragDrop' event when the users drags some files onto the element

We can run and test the application to see if everything works. Then we have to switch the setting to compile it as a .dll library so it can be called by GuiXT.

That means we create a container with GuiXT and embed this application into it on the sap gui screen. In our case we will embed just a very small application, displaying a single image onto which the user can drag&drop files.

Imports guinet

Public Class Form1

    Dim g As New guixt
    Private Sub Form1_Load(sender As Object, e As EventArgs) _
        Handles MyBase.Load

        PictureBox1.AllowDrop = True
    End Sub

    Private Sub PictureBox1_DragEnter_1(sender As Object,
                                        e As DragEventArgs) _
        Handles PictureBox1.DragEnter

        ' SET THE PROPER ACTION FOR FILE DROP....
        ' BY USING THE FILEDROP METHOD TO COPY

        If e.Data.GetDataPresent(DataFormats.FileDrop) Then
            e.Effect = DragDropEffects.Link
        Else
            e.Effect = DragDropEffects.None
        End If

    End Sub

    Private Sub PictureBox1_DragDrop_1(sender As Object,
                                       e As DragEventArgs) _
        Handles PictureBox1.DragDrop

        Try

            If e.Data.GetDataPresent("FileDrop", True) = True Then
                Dim Werte As String() =
                    CType(e.Data.GetData("FileDrop"), Object)
                ' 
                Dim fileNames As String = ""

                Dim i As Integer = 0
                For Each f In Werte

                    g.SetVariable("dragged_files." _
                     & (i + 1).ToString, Werte(i))

                    i += 1
                Next

                ' Get name of InputScript
                Dim inputScript As String = ""
                inputScript = g.GetVariable("dragdrop_inputscript")

                ' Start InputScript ...
                g.Input("OK:/0,process=" & inputScript)

            End If

        Catch ex As Exception
            MsgBox(ex.Message)
        End Try

    End Sub

    Public Sub embed(ByVal w As Object, imagepath As String)

        Try
            If Not imagepath = "" Then
                PictureBox1.Image = Image.FromFile(imagepath)
            End If
            guixt.EmbedForm(Me, w)

        Catch ex As Exception

            MsgBox(ex.Message)

        End Try

    End Sub

End Class

// Create a container to embed our windows form control
Control (-0.4,99.8) (5.2,136.1) progID="Shell.Explorer" _
  ="r1" initFlag="r1init" -closeOnHide

// Define the script that will be run after a user dropped files
Set V[dragdrop_inputscript] "va03_drop_files.txt"

// Embed the control into our container
if V[r1init]

CallVB draganddrop.form1.embed w:="&V[r1]"    _
  imagepath:="C:\guixtscripts\draghere_2.png"

endif

if not V[rows]

  Set V[rows] "10"

endif

Table     (0,162)  (10,223) title="Dropped Files" _ 
  name="droppedfiles" rows="&V[rows]"

Column "Filename" size=60 name="col1"

Here is the InputScript that is processed after the user has dragged files onto the control:

Set V[i] 1
clear V[droppedfiles.cell.*]

label nextRow

if V[dragged_files.&V[i]]

  Set V[droppedfiles.cell.col1.&V[i]] "&V[dragged_files.&V[i]]"
  Set V[i] "&V[i]" + 1

  goto nextRow

  endif

Set V[rows] "&V[i]"
clear V[dragged_files.*]

return

Result:

You can download all files for this example here:
DragAndDrop.zip

Here is video with further details about the project:

Components
InputAssistant + Controls