public static HRESULT DoDragDrop(
IDataObject pDataObj,
IDropSource pDropSource,
DROPEFFECT dwOKEffects,
out DROPEFFECT pdwEffect)
{
var result = WinFormsComWrappers.Instance.TryGetComPointer(pDataObj, IID.IDataObject, out var dataObjectPtr);
if (result.Failed())
{
pdwEffect = DROPEFFECT.NONE;
return(result);
}
result = WinFormsComWrappers.Instance.TryGetComPointer(pDropSource, IID.IDropSource, out var dropSourcePtr);
if (result.Failed())
{
Marshal.Release(dataObjectPtr);
pdwEffect = DROPEFFECT.NONE;
return(result);
}
result = DoDragDrop(dataObjectPtr, dropSourcePtr, dwOKEffects, out pdwEffect);
return(result);
}
/// <summary>
/// Helper method to call the Mshtml DragOver routine using .NET DragEventArgs
/// </summary>
/// <param name="e"></param>
private void CallMshtmlDragOver(DragEventArgs e, bool allowEffects, bool allowExceptions)
{
if (mshtmlDropTargetImpl == null)
{
return;
}
try
{
// convert data types
POINT pt = new POINT(); pt.x = e.X; pt.y = e.Y;
DROPEFFECT dropEffect = ConvertDropEffect(e.AllowedEffect);
MK keyState = ConvertKeyState(e.KeyState);
// suppress effects if requested
if (!allowEffects)
{
dropEffect = DROPEFFECT.NONE;
}
// call mshtml
mshtmlDropTargetImpl.DragOver(keyState, pt, ref dropEffect);
// copy any changes to the dropEffect back into the event args
e.Effect = ConvertDropEffect(dropEffect);
}
catch (Exception)
{
if (allowExceptions)
{
throw;
}
}
}
/// <summary>
/// Helper to cal the Mshtml DragDrop routine using .NET DragEventArgs
/// </summary>
/// <param name="e">event args</param>
private void CallMshtmlDragDrop(DragEventArgs e, bool allowExceptions)
{
if (mshtmlDropTargetImpl == null)
{
return;
}
try
{
// extract ole data object
IOleDataObject oleDataObject = SafeExtractOleDataObject(e.Data);
// convert data types
POINT pt = new POINT(); pt.x = e.X; pt.y = e.Y;
DROPEFFECT dropEffect = ConvertDropEffect(e.AllowedEffect);
MK keyState = ConvertKeyState(e.KeyState);
// call mshtml
mshtmlDropTargetImpl.Drop(oleDataObject, keyState, pt, ref dropEffect);
// copy any changes to the dropEffect back into the event args
e.Effect = ConvertDropEffect(dropEffect);
}
catch (Exception)
{
if (allowExceptions)
{
throw;
}
}
}
/// <inheritdoc/>
HRESULT IDropTarget.DragOver(MouseButtonState grfKeyState, POINT pt, ref DROPEFFECT pdwEffect)
{
System.Diagnostics.Debug.WriteLine($"IDropTarget.DragOver: effect={pdwEffect}");
var drgevent = CreateDragEventArgs(null, grfKeyState, pt, pdwEffect);
DragOver?.Invoke(this, drgevent);
lastEffect = pdwEffect = drgevent.Effect;
return(HRESULT.S_OK);
}
/// <summary>Initializes a new instance of the <see cref="DragEventArgs"/> class.</summary>
/// <param name="data">The data associated with this event.</param>
/// <param name="keyState">The current state of the SHIFT, CTRL, and ALT keys.</param>
/// <param name="x">The x-coordinate of the mouse cursor in pixels.</param>
/// <param name="y">The y-coordinate of the mouse cursor in pixels.</param>
/// <param name="allowedEffect">One of the DROPEFFECT values.</param>
/// <param name="lastEffect">One of the DROPEFFECT values.</param>
public DragEventArgs(IDataObject data, MouseButtonState keyState, int x, int y, DROPEFFECT allowedEffect, DROPEFFECT lastEffect)
{
Data = data;
KeyState = keyState;
X = x;
Y = y;
AllowedEffect = allowedEffect;
Effect = lastEffect;
}
/// <inheritdoc/>
HRESULT IDropTarget.DragEnter(IDataObject pDataObj, MouseButtonState grfKeyState, Point pt, ref DROPEFFECT pdwEffect)
{
System.Diagnostics.Debug.WriteLine($"IDropTarget.DragEnter: effect={pdwEffect}");
var drgevent = CreateDragEventArgs(pDataObj, grfKeyState, pt, pdwEffect);
DragEnter?.Invoke(this, drgevent);
lastEffect = pdwEffect = (DROPEFFECT)drgevent.Effect;
return(HRESULT.S_OK);
}
/// <inheritdoc/>
HRESULT IDropTarget.Drop(IDataObject pDataObj, uint grfKeyState, Point pt, ref DROPEFFECT pdwEffect)
{
System.Diagnostics.Debug.WriteLine($"IDropTarget.Drop: effect={pdwEffect}");
var drgevent = CreateDragEventArgs(pDataObj, grfKeyState, pt, pdwEffect);
DragDrop?.Invoke(this, drgevent);
pdwEffect = (DROPEFFECT)drgevent.Effect;
CancelTimeout();
return(HRESULT.S_OK);
}
// this method is what is called to invoke the verb and is typically the only method that needs to be implemented this is the method
// that is called to invoke the verb the data object represents the selection and is converted into a shell item array to address the
// items being acted on.
HRESULT IDropTarget.Drop(IDataObject pDataObj, uint grfKeyState, Point pt, ref DROPEFFECT pdwEffect)
{
_pdtobj = pDataObj;
// capture state from the site, the HWND of the parent (that should not be used for a modal
// window) but might be useful for positioning the UI of this verb
IUnknown_GetWindow(_punkSite, out _hwnd);
QueueAppCallback();
pdwEffect = DROPEFFECT.DROPEFFECT_NONE; // didn't move or copy the file
return(HRESULT.S_OK);
}
/// <summary>
/// Helper to convert Win32 drop effect into .NET drop effect
/// </summary>
/// <param name="dropEffect">drop effect to convert</param>
/// <returns>converted effect</returns>
public static DragDropEffects ConvertDropEffect(DROPEFFECT dropEffect)
{
DragDropEffects targetDropEffect = DragDropEffects.None;
if ((dropEffect & DROPEFFECT.COPY) == DROPEFFECT.COPY)
{
targetDropEffect |= DragDropEffects.Copy;
}
if ((dropEffect & DROPEFFECT.LINK) == DROPEFFECT.LINK)
{
targetDropEffect |= DragDropEffects.Link;
}
if ((dropEffect & DROPEFFECT.MOVE) == DROPEFFECT.MOVE)
{
targetDropEffect |= DragDropEffects.Move;
}
if ((dropEffect & DROPEFFECT.SCROLL) == DROPEFFECT.SCROLL)
{
targetDropEffect |= DragDropEffects.Scroll;
}
return(targetDropEffect);
}
/// <summary>
/// Helper to convert .NET drop-effect into Win32 drop effect
/// </summary>
/// <param name="dropEffect">drop effect to convert</param>
/// <returns>converted effect</returns>
public static DROPEFFECT ConvertDropEffect(DragDropEffects dropEffect)
{
DROPEFFECT targetDropEffect = DROPEFFECT.NONE;
if ((dropEffect & DragDropEffects.Copy) == DragDropEffects.Copy)
{
targetDropEffect |= DROPEFFECT.COPY;
}
if ((dropEffect & DragDropEffects.Link) == DragDropEffects.Link)
{
targetDropEffect |= DROPEFFECT.LINK;
}
if ((dropEffect & DragDropEffects.Move) == DragDropEffects.Move)
{
targetDropEffect |= DROPEFFECT.MOVE;
}
if ((dropEffect & DragDropEffects.Scroll) == DragDropEffects.Scroll)
{
targetDropEffect |= DROPEFFECT.SCROLL;
}
return(targetDropEffect);
}
public override DragDropEffects ProvideDragFeedback(Point screenPoint, int keyState, DragDropEffects supportedEffects)
{
if (_unhandledDropTarget == null)
{
return(DragDropEffects.None);
}
_mkKeyState = MshtmlEditorDragAndDropTarget.ConvertKeyState(keyState);
_effect = MshtmlEditorDragAndDropTarget.ConvertDropEffect(supportedEffects);
_point = new POINT();
_point.x = screenPoint.X;
_point.y = screenPoint.Y;
// We have to call begin drag here because we need the location and key state which we dont have in BeginDrag()
if (!_hasCalledBeginDrag)
{
_hasCalledBeginDrag = true;
_unhandledDropTarget.DragEnter(_oleDataObject, _mkKeyState, _point, ref _effect);
}
_unhandledDropTarget.DragOver(_mkKeyState, _point, ref _effect);
return(MshtmlEditorDragAndDropTarget.ConvertDropEffect(_effect));
}
private DragEventArgs CreateDragEventArgs(IDataObject pDataObj, MouseButtonState grfKeyState, Point pt, DROPEFFECT pdwEffect)
{
var data = pDataObj == null ? lastDataObject : new DataObject(pDataObj);
var drgevent = new DragEventArgs(data, (int)grfKeyState, pt.X, pt.Y, (DragDropEffects)pdwEffect, (DragDropEffects)lastEffect);
lastDataObject = data;
return(drgevent);
}
public override DragDropEffects ProvideDragFeedback(Point screenPoint, int keyState, DragDropEffects supportedEffects)
{
if (_unhandledDropTarget == null)
return DragDropEffects.None;
_mkKeyState = MshtmlEditorDragAndDropTarget.ConvertKeyState(keyState);
_effect = MshtmlEditorDragAndDropTarget.ConvertDropEffect(supportedEffects);
_point = new POINT();
_point.x = screenPoint.X;
_point.y = screenPoint.Y;
// We have to call begin drag here because we need the location and key state which we dont have in BeginDrag()
if (!_hasCalledBeginDrag)
{
_hasCalledBeginDrag = true;
_unhandledDropTarget.DragEnter(_oleDataObject, _mkKeyState, _point, ref _effect);
}
_unhandledDropTarget.DragOver(_mkKeyState, _point, ref _effect);
return MshtmlEditorDragAndDropTarget.ConvertDropEffect(_effect);
}
/// <summary>
/// Helper to convert Win32 drop effect into .NET drop effect
/// </summary>
/// <param name="dropEffect">drop effect to convert</param>
/// <returns>converted effect</returns>
public static DragDropEffects ConvertDropEffect(DROPEFFECT dropEffect)
{
DragDropEffects targetDropEffect = DragDropEffects.None;
if ((dropEffect & DROPEFFECT.COPY) == DROPEFFECT.COPY)
targetDropEffect |= DragDropEffects.Copy;
if ((dropEffect & DROPEFFECT.LINK) == DROPEFFECT.LINK)
targetDropEffect |= DragDropEffects.Link;
if ((dropEffect & DROPEFFECT.MOVE) == DROPEFFECT.MOVE)
targetDropEffect |= DragDropEffects.Move;
if ((dropEffect & DROPEFFECT.SCROLL) == DROPEFFECT.SCROLL)
targetDropEffect |= DragDropEffects.Scroll;
return targetDropEffect;
}
public void SetParameters(uint KeyState, System.Drawing.Point pt, DataObject DropDataObject, uint Effect)
{
this.handled = false;
this.keystate = KeyState;
this.pt = pt;
this.dropeffect = (DROPEFFECT)Effect;
this.dataobject = DropDataObject;
}
/// <summary>
/// Provides target feedback to the user and communicates the drop's effect to the DoDragDrop function so it can communicate the effect of the drop back to the source
/// </summary>
/// <param name="grfKeyState">Current state of the keyboard modifier keys on the keyboard</param>
/// <param name="pt">POINTL structure containing the current cursor coordinates in screen coordinates</param>
/// <param name="pdwEffect">Pointer to the current effect flag. Valid values are from the enumeration DROPEFFECT</param>
void OpenLiveWriter.Interop.Com.IDropTarget.DragOver(MK grfKeyState, POINT pt, ref DROPEFFECT pdwEffect)
{
Debug.Fail("Unexpected call to IDropTarget.DragOver");
if (mshtmlDropTargetImpl != null)
{
mshtmlDropTargetImpl.DragOver(grfKeyState, pt, ref pdwEffect);
}
}
private DragEventArgs CreateDragEventArgs(IDataObject pDataObj, MouseButtonState grfKeyState, POINT pt, DROPEFFECT pdwEffect)
{
var data = pDataObj ?? lastDataObject;
var drgevent = new DragEventArgs(data, grfKeyState, pt.X, pt.Y, pdwEffect, lastEffect);
lastDataObject = data;
return(drgevent);
}
/// <summary>
/// Incorporates the source data into the target window, removes target feedback, and releases the data object
/// </summary>
/// <param name="pDataObj">Pointer to the IDataObject interface on the data object being transferred in the drag-and-drop operation</param>
/// <param name="grfKeyState">Current state of the keyboard modifier keys on the keyboard</param>
/// <param name="pt">POINTL structure containing the current cursor coordinates in screen coordinates</param>
/// <param name="pdwEffect">Pointer to the current effect flag. Valid values are from the enumeration DROPEFFECT</param>
void OpenLiveWriter.Interop.Com.IDropTarget.Drop(IOleDataObject pDataObj, MK grfKeyState, POINT pt, ref DROPEFFECT pdwEffect)
{
Debug.Fail("Unexpected call to IDropTarget.Drop");
if (mshtmlDropTargetImpl != null)
{
mshtmlDropTargetImpl.Drop(pDataObj, grfKeyState, pt, ref pdwEffect);
}
}
public static extern HRESULT DoDragDrop(
IDataObject pDataObj,
IDropSource pDropSource,
DROPEFFECT dwOKEffects,
out DROPEFFECT pdwEffect);
// IDropTarget this is the required interface for a verb implemeting the DropTarget method DragEnter is called to enable the // implementaiton to zero the output dwEffect value, indicating that the verb does not accept the input data object. this is rarely used. HRESULT IDropTarget.DragOver(uint grfKeyState, Point pt, ref DROPEFFECT pdwEffect) => HRESULT.S_OK;
HRESULT IDropTarget.DragEnter(IDataObject pDataObj, MouseButtonState grfKeyState, Point pt, ref DROPEFFECT pdwEffect) => HRESULT.S_OK;
/// <summary>
/// Provides target feedback to the user and communicates the drop's effect to the DoDragDrop function so it can communicate the effect of the drop back to the source
/// </summary>
/// <param name="grfKeyState">Current state of the keyboard modifier keys on the keyboard</param>
/// <param name="pt">POINTL structure containing the current cursor coordinates in screen coordinates</param>
/// <param name="pdwEffect">Pointer to the current effect flag. Valid values are from the enumeration DROPEFFECT</param>
void OpenLiveWriter.Interop.Com.IDropTarget.DragOver(MK grfKeyState, POINT pt, ref DROPEFFECT pdwEffect)
{
Debug.Fail("Unexpected call to IDropTarget.DragOver");
if (mshtmlDropTargetImpl != null)
{
mshtmlDropTargetImpl.DragOver(grfKeyState, pt, ref pdwEffect);
}
}
public static extern int DoDragDrop(
IOleDataObject pDataObject, // Pointer to the data object
IDropSource pDropSource, // Pointer to the source
DROPEFFECT dwOKEffect, // Effects allowed by the source
ref DROPEFFECT pdwEffect // Pointer to effects on the source
);
/// <summary>
/// Incorporates the source data into the target window, removes target feedback, and releases the data object
/// </summary>
/// <param name="pDataObj">Pointer to the IDataObject interface on the data object being transferred in the drag-and-drop operation</param>
/// <param name="grfKeyState">Current state of the keyboard modifier keys on the keyboard</param>
/// <param name="pt">POINTL structure containing the current cursor coordinates in screen coordinates</param>
/// <param name="pdwEffect">Pointer to the current effect flag. Valid values are from the enumeration DROPEFFECT</param>
void OpenLiveWriter.Interop.Com.IDropTarget.Drop(IOleDataObject pDataObj, MK grfKeyState, POINT pt, ref DROPEFFECT pdwEffect)
{
Debug.Fail("Unexpected call to IDropTarget.Drop");
if (mshtmlDropTargetImpl != null)
{
mshtmlDropTargetImpl.Drop(pDataObj, grfKeyState, pt, ref pdwEffect);
}
}
private static extern HRESULT DoDragDrop(
IntPtr pDataObj,
IntPtr pDropSource,
DROPEFFECT dwOKEffects,
out DROPEFFECT pdwEffect);
// IDropTarget this is the required interface for a verb implemeting the DropTarget method DragEnter is called to enable the // implementaiton to zero the output dwEffect value, indicating that the verb does not accept the input data object. this is rarely used. HRESULT IDropTarget.DragOver(MouseButtonState grfKeyState, Point pt, ref DROPEFFECT pdwEffect) => HRESULT.S_OK;
public static extern int DoDragDrop(
IOleDataObject pDataObject, // Pointer to the data object
IDropSource pDropSource, // Pointer to the source
DROPEFFECT dwOKEffect, // Effects allowed by the source
ref DROPEFFECT pdwEffect // Pointer to effects on the source
);
