bool g_fDragging;
void Main_OnBeginDrag(HWND hwndTV, LPNMTREEVIEW lpnmtv) 
{ 
    HIMAGELIST himl;    // handle to image list 
    RECT rcItem;        // bounding rectangle of item 
    DWORD dwLevel;      // heading level of item 
    DWORD dwIndent;     // amount that child items are indented 

    // Tell the tree view control to create an image to use 
    // for dragging. 
    himl = TreeView_CreateDragImage(hwndTV, lpnmtv->itemNew.hItem); 

    // Get the bounding rectangle of the item being dragged. 
    TreeView_GetItemRect(hwndTV, lpnmtv->itemNew.hItem, &rcItem, TRUE); 

    // Get the heading level and the amount that the child items are 
    // indented. 
    dwLevel = lpnmtv->itemNew.lParam; 
    dwIndent = (DWORD) SendMessage(hwndTV, TVM_GETINDENT, 0, 0); 

    // Start the drag operation. 
    ImageList_BeginDrag(himl, 0, -5, -5); 

    // Hide the mouse cursor, and direct mouse input to the 
    // parent window. 
    ShowCursor(FALSE); 
    SetCapture(GetParent(hwndTV)); 
    g_fDragging = true; 
    return; 
} 

void Main_OnMouseMove(HWND hwndParent, HWND hwndTV, LONG xCur, LONG yCur) 
{ 
    HTREEITEM htiTarget;  // handle to target item 
    TVHITTESTINFO tvht;  // hit test information 

    if( g_fDragging ) { 

        // Drag the item to the current position of the mouse cursor. 
        ImageList_DragMove(xCur, yCur); 

        // Find out if the cursor is on the item. If it is, highlight 
        // the item as a drop target. 
        tvht.pt.x = xCur; 
        tvht.pt.y = yCur; 
        if( (htiTarget = TreeView_HitTest(hwndTV, &tvht)) != NULL ) { 
			TreeView_SelectDropTarget(hwndTV, htiTarget);
        } 
    } 
    return; 
}

Und dann das noch in meiner Nachrichtenschleife.

case TVN_BEGINDRAG:
				Main_OnBeginDrag(TreeView.GetHwnd(), (LPNMTREEVIEW) lP); 
				break; 
			}
		}
		break;
			case WM_MOUSEMOVE:
				if( g_fDragging == true )
					Main_OnMouseMove(hdlg, TreeView.GetHwnd(), LOWORD(lP), HIWORD(lP));
				break;
			case WM_LBUTTONUP:
				if( g_fDragging )
				{ 
					ImageList_EndDrag();
					ReleaseCapture();
					ShowCursor(TRUE); 
					g_fDragging = false;
				}

Also wenn ich diese Zeile auskommentiere

TreeView_SelectDropTarget(hwndTV, htiTarget);

Dann funktioniert es danach auch wieder aber dann wird beim Ziehen ja nix markiert???
Hoffe jemand kann mir helfen. Evtl ist es noch wichtig zu wissen das das TreeView in einem Dialogbox ist das untergeordnet arbeitet, also das ist in einem TabCtrl vielleicht hängt es ja damit zusammen??

MfG schirrmie

MfG schirrmie