DragDropClient Class |  |
Create the client for use in a drag-and-drop operation.
Inheritance HierarchyNamespace: VO
Assembly: VOGUIClasses (in VOGUIClasses.dll) Version: 2.21
SyntaxThe DragDropClient type exposes the following members.
Constructors| Name | Description | |
|---|---|---|
 | DragDropClient |
Construct a drag-and-drop client.
Important! Normally, this method should not be called in your application code. Instead use Window:EnableDragDropClient(TRUE) to create a drag-and-drop client. |
Methods| Name | Description | |
|---|---|---|
| Dispatch | |
| DragLeave |
Notify the application that the mouse has left the client area of the window that owns the drag-and-drop client.
|
| DragOver |
Notify the application of a DragOver event and accept or reject the drop.
|
| Drop |
Retrieve information about a load from the drag event and act on each file in the selection.
|
Fields
Remarks
In Windows, "drag-and-drop" is a technique by which users can move files from one location to another, either visually (using the mouse) or through another system-accepted method. The client in a drag-and-drop operation is a utility object with an associated owner window that accepts dropped files.
Creating a drag-and-drop client automatically makes its owner window capable of accepting drag-and-drop loads. The event handlers in the drag-and-drop client handle the events relevant to the drag-and-drop operation.
Important! When you call Window:EnableDragDropClient(TRUE), the window becomes a DragDropClient and inherits all the methods of DragDropClient. The callback methods DragLeave(), DragOver(), and Drop() are called on the Window object when a DragLeave, DragOver, or Drop event occurs (see the example below.)
Important! When you call Window:EnableDragDropClient(TRUE), the window becomes a DragDropClient and inherits all the methods of DragDropClient. The callback methods DragLeave(), DragOver(), and Drop() are called on the Window object when a DragLeave, DragOver, or Drop event occurs (see the example below.)
Examples
The following example demonstrates the use of the DragDropClient class:
X#
1METHOD Init(oOwner) CLASS StandardShellWindow 2SUPER:Init(oOwner) 3SELF:Size := Dimension{300,100} 4SELF:Origin:= Point{0,20} 5SELF:Caption := "Non-MDI ChildWindow" 6SELF:EnableMinBox() 7SELF:EnableMaxBox() 8SELF:EnableSystemMenu 9SELF:EnableBorder() 10SELF:EnableDragDropClient() // Make the window a DragDropClient 11SELF:Show() 12METHOD DragOver(oDragEvent) CLASS StandardShellWindow 13LOCAL iCount AS INT 14LOCAL iAcceptDrop AS LOGIC 15// Check files that are being dragged over the window 16// Only accept if all files are .DBF 17lAcceptDrop := TRUE 18FOR iCount := 1 TO oDragEvent:FileCount 19IF RAT(".DBF", oDragEvent:FileName(iCount)) == 0 20lAcceptDrop := FALSE 21EXIT 22ENDIF 23NEXT 24RETURN lAcceptDrop 25METHOD DragLeave() CLASS StandardShellWindow 26// Undo any actions taken during drag-drop attempt 27METHOD Drop(oDragEvent) CLASS StandardShellWindow 28LOCAL nNumFiles := oDragEvent:FileCount 29// Number of entries dropped 30LOCAL nFile AS INT 31// For each item that is dropped, if it is a file, open it. 32FOR nFile := 1 TO nNumFiles 33IF File(oDragEvent:FileName(nFile)) 34SELF:DoOpenFile(oDragEvent:FileName(nFile)) 35ENDIF 36NEXT
See Also