asked on

Dragging an item

I want to click item in the ListBox and then drag the item somewhere on other component (eg. other ListBox), but I want the item still to appear under the cursor while draging. To be more exact, I want to drag name of font from the font list and drop it to some text in other component and by this to change font of the text. How can be this effect achieved?

atul_parmar

e.g. ListBox1 contains the font names then
Set the following
1. ListBox1.Drag Mode = dgAutomatic;
2. ListBox1.Tag := -1; // this will track the item to drag

in the OnMouseDown of ListBox1 write the following line

ListBox1.Tag := ListBox1.ItemAtPos(Point(X, Y), True);

in the OnDragOver event of other control put the following line

Accept := ListBox1.Tag > -1;

in the OnDragDrop event of other control put the following code

if ListBox1.Tag > -1 then
begin
Edit1.Font.Name := ListBox1.Items.Strings[ListBox1.Tag]; // assuming that the item is being dragged to edit box
ListBox1.Tag := -1; // reset the dragged item
end;

JackKuti

ASKER

Thanks, font are changed perfectly, but still, I´d like to achieve the effect of appearing of font name under the cursor while draging it from ListBox untill it is dropped down. This is not necessary for the application to work but its nice.

ASKER CERTIFIED SOLUTION

Russell Libby

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JackKuti

ASKER

Thanks for your code. And don´t you know how to remove the crossed ring being displayed while dragging?

Russell Libby

Are you sure you want to do that? Its the only UI cue to the user when a drop operation cannot be performed.

Russell

Russell Libby

////////////////////////////////////////////////////////////////////////////////
// TTextDrag
////////////////////////////////////////////////////////////////////////////////
type
TTextDrag = class(TDragObject)
private
// Private declarations
FDragImage: TDragImageList;
FText: String;
protected
// Protected declarations
function GetDragCursor(Accepted: Boolean; X, Y: Integer): TCursor; override; // ADD
function GetDragImages: TDragImageList; override;
public
// Public declarations
constructor Create;
destructor Destroy; override;
procedure UpdateDragImage(Font: TFont; Text: String);
property Text: String read FText;
end;

etc....

implementation
{$R *.DFM}

function TTextDrag.GetDragCursor(Accepted: Boolean; X, Y: Integer): TCursor;
begin

// Perform inherited
result:=inherited GetDragCursor(Accepted, X, Y);

// Check accepted = false. You can also remove this check and always return zero
// which will make it use the default cursor
if not(Accepted) then result:=0;

end;

JackKuti

ASKER

Trying if it looks better without the ring, if it won´t the ring will be returned. Many thanks to you!