Drag & Drop an Item into ArcMap

[MickeyO_Neil]

Hello,

I am looking for the right Object Typ to put in the DoDragDrop() Function.
I tried it with an IName Object and an IDataObject but ArcMap does not accept these Typs.
The Drag&Drop even works with the Windows Explorer so it musst be a common Object Typ. I bet this is somewhere in the "ArcObjects Help" but I can't find it, sorry. 🙂

My Item schould be draged out of a TreeView into ArcMap. Thats my Code:

Private Sub tvTree_ItemDrag(ByVal sender As Object, ByVal e As System.Windows.Forms.ItemDragEventArgs) Handles tvTree.ItemDrag          'Get the IName Object of the TreeNode         Dim pTreeNode As TreeNode         pTreeNode = e.Item          Dim pclsTreeNode As clsTreeNode         pclsTreeNode = pTreeNode.Tag          Dim pName As IName         pName = pclsTreeNode.NodeObject          If Not pName Is Nothing Then              'Create IData Object              Dim pDataObject As Windows.Forms.IDataObject             pDataObject = New Windows.Forms.DataObject             pDataObject.SetData(pName)              DoDragDrop(pDataObject, DragDropEffects.All)         End If     End Sub

[MickeyO_Neil]

Hi,

...I figured out, that the Object has to be an Array with the Path of the draged file or an IEnumName Object.
Because that's the code which acceps the Drag Event:

 If action = esriControlsDropAction.esriDropped Then
        'If the data is from Windows Explorer.
        If pDataObject.CanGetFiles Then
            'Get an array of file paths through the IDataObjectHelper.
            pFilePaths = pDataObject.GetFiles
            'Loop through the array.
            For i = LBound(pFilePaths) To UBound(pFilePaths)
                'If a valid Mx document, load it into the MapControl.
                If AxMapControl1.CheckMxFile(pFilePaths(i)) Then
                    AxMapControl1.LoadMxFile(pFilePaths(i))
                Else
                    'Get the IFileName interface and set its path.
                    pFileName = New FileNameClass
                    pFileName.Path = pFilePaths(i)
                    'Create a map layer.
                    CreateLayer(CType(pFileName, IName))
                End If
            Next
            'If data is from ArcCatalog.
        ElseIf pDataObject.CanGetNames Then
            'Get the IEnumName interface through the IDataObjectHelper.
            pEnumName = pDataObject.GetNames
            pEnumName.Reset()
            'Get the IName interface.
            pName = pEnumName.Next
            'Loop through the names.
            Do While Not pName Is Nothing
                'Create a map layer.
                CreateLayer(pName)
                pName = pEnumName.Next
            Loop
        End If
    End If

But it still does not work. Maybe the "DoDragDrop" Function is a wrong choice to fire the "AxMapControl1_OnOleDrop" Event.

[MickeyO_Neil · Accepted solution]

It finally works 🙂
You need a MemoryStream to set Data into a DataObject 😛

  Private Sub tvTree_ItemDrag(ByVal sender As Object, ByVal e As System.Windows.Forms.ItemDragEventArgs) Handles tvTree.ItemDrag         Try              'Get the IName Object (I stored it in the Tag of the TreeNode)             Dim pTreeNode As TreeNode             pTreeNode = e.Item              'My Class where I stored the IName and some other stuff             Dim pclsTreeNode As clsTreeNode             pclsTreeNode = pTreeNode.Tag              Dim pName As IName             pName = pclsTreeNode.NodeObject              If Not pName Is Nothing Then                 '----- For ArcMap -----                  'Put the IName in an IEnumName                 Dim pNameFactory As INameFactory                 pNameFactory = New NameFactory                  Dim pEnumName As IEnumName                 pEnumName = New NamesEnumerator                 Dim pEnumNameEdit As IEnumNameEdit                 pEnumNameEdit = pEnumName                 pEnumNameEdit.Add(pName)                  'Create DataObject                 Dim pDataObject As Windows.Forms.IDataObject                 pDataObject = New Windows.Forms.DataObject                   'To fill the DataObject you need a MemoryStream!                 Dim pMemoryStream As System.IO.MemoryStream                 pMemoryStream = New System.IO.MemoryStream(CType(pNameFactory.PackageNames(pEnumNameEdit), Byte()))                 pDataObject.SetData("ESRI Names", pMemoryStream)                  'Fire the DragGropEvent                 tvTree.DoDragDrop(pDataObject, DragDropEffects.All)             Else                 '----- For Windows Explorer -----                  'For the Internet Explorer you just need the Path of the File and put it into an Array of String                 Dim pArrayOfString(0) As String                 pArrayOfString(0) = pclsTreeNode.Path                  Dim pDataObject As Windows.Forms.IDataObject                 pDataObject = New Windows.Forms.DataObject                  pDataObject.SetData(DataFormats.FileDrop, pArrayOfString)                 tvTree.DoDragDrop(pDataObject, DragDropEffects.All)             End If         Catch ex As Exception             DoErrorHandling(ex, Reflection.MethodInfo.GetCurrentMethod)         End Try     End Sub