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WindowsDragSourceMBS class

Type Topic Plugin Version macOS Windows Linux iOS Targets
class Drag & Drop MBS Win Plugin 10.5 ❌ No ✅ Yes ❌ No ❌ No Desktop, Console & Web
The class for Drag and Drop on Windows to create a drag source.

The WindowsDragSourceMBS class is one of the class you implement to provide drag-and-drop operations in your application. It contains methods used in any application used as a data source in a drag-and-drop operation. The data source application in a drag-and-drop operation is responsible for:

  • Determining the data being dragged based on the user's selection.
  • Initiating the drag-and-drop operation based on the user's mouse actions.
  • Generating some of the visual feedback during the drag-and-drop operation, such as setting the cursor and highlighting the data selected for the drag-and-drop operation.
  • Canceling or completing the drag-and-drop operation based on the user's mouse actions.
  • Performing any action on the original data caused by the drop operation, such as deleting the data on a drag move.

WindowsDragSourceMBS contains the events for generating visual feedback to the end user and for canceling or completing the drag-and-drop operation.

When To Implement

Implement WindowsDragSourceMBS if you are developing a container or server application that can act as a data source for a drag-and-drop operation. The WindowsDragSourceMBS interface is only required during the drag-and-drop operation.

If you implement the WindowsDragSourceMBS class, you must also implement the DataObjectMBS class on the same object to represent the data being transferred.

You can use the same implementation of DataObjectMBS for drag-and-drop data as for the data object offered to the clipboard. After you have implemented clipboard operations in your application, you can add drag-and-drop operations with only a little extra work.

When To Use

You do not usually call the WindowsDragSourceMBS methods directly. Instead, your data source calls the DoDragDrop function when it detects that the user has initiated a drag-and-drop operation. Then, DoDragDrop calls the WindowsDragSourceMBS methods during the drag-and-drop operation.

For example, DoDragDrop calls WindowsDragSourceMBS.GiveFeedback when you need to change the cursor shape or when you need to provide some other visual feedback. DoDragDrop calls WindowsDragSourceMBS.QueryContinueDrag when there is a change in the mouse button state to determine if the drag-and-drop operation was canceled or completed.

While the drag classes compile for Web Edition, they run on the server, so they have no effect on the client browser!

Constants

Constant Value Description
DRAGDROP_S_CANCEL &H00040101 One of the OLE error codes. Drag and Drop was cancelled.
DRAGDROP_S_DROP &h00040100 One of the OLE error codes. Do the drop operation.
DRAGDROP_S_USEDEFAULTCURSORS &h00040102 One of the OLE error codes.
DROPEFFECT_COPY 1 One of the drop effect constants. Drop results in a copy. The original data is untouched by the drag source. more
DROPEFFECT_LINK 4 One of the drop effect constants. Drag source should create a link to the original data.
DROPEFFECT_MOVE 2 One of the drop effect constants. Drag source should remove the data.
DROPEFFECT_NONE 0 One of the drop effect constants. Drop target cannot accept the data.
DROPEFFECT_SCROLL &h80000000 One of the drop effect constants. Scrolling is about to start or is currently occurring in the target. This value is used in addition to the other values.
MK_CONTROL 8 One of the key state constants. The CTRL key is down.
MK_LBUTTON 1 One of the key state constants. The left mouse button is down.
MK_MBUTTON &h10 One of the key state constants. The middle mouse button is down.
MK_RBUTTON 2 One of the key state constants. The right mouse button is down.
MK_SHIFT 4 One of the key state constants. The SHIFT key is down.
MK_XBUTTON1 &h20 One of the key state constants. The first X button is down.
MK_XBUTTON2 &h40 One of the key state constants. The second X button is down.
S_FALSE 1 One of the OLE error codes.
S_OK 0 One of the OLE error codes.

This class has no sub classes.

Some examples using this class:

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The items on this page are in the following plugins: MBS Win Plugin.


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