The LA Fox Developer Newsletter

June 1995

Drag and Drop (Con't from page 4)

The first three properties give us a convenient place

to store names of cursors; the DragThreshold num-

ber will tell us how far the left-clicked mouse needs

to move before we know the user wants to Drag-

and-Drop; and the MouseX and MouseY properties

are just temporary places to put the mouse location

information when we need it.

The following code goes into the lNlT method of the

form:

This code reads REPORT. DBF and populates the

source ListBox (IstSource) for us. It also populates

the aReports array with the corresponding names of

report files for each report description.

So that’s it for the form.. .six properties and some

INIT code.

An aside...

Although not absolutely necessary, the OK button

has a Click event that reads: RELEASE THISFORM.

This will close the form and shoot you back to VFP,

the same as a double-click in the control box in the

upper left corner of the form. I always use a button

to close the form unless users have a background

with the Macintosh. Now back to the good stuff...

The Drag-and-Drop Source

The Drag-and-Drop source is the object “lstSource”,

a ListBox holding the descriptions of system reports.

We need to modify three methods in this object.

The DragOver method should read:

Remember creating the CanSourcetcon property for

the form? This is where we use it. Same for

NoDroplcon. This code here changes the cursor as

the user moves it out of the ListBox, from an arrow

with a box next to it to a cirle & slash cursor like

those on No Smoking signs.. Impressive stuff for so

little work.

2.

The MouseDown method should read:

Remember creating the Mousex and MouseY prop-

erties for the form? We use those now to record the

starting position of the mouse when the left mouse

button is first pressed.

3. The MouseMove property should read:

Remember adding Draglhreshold as a property for

the Form? Remember entering “8” in this property?

This code enables Dragging of the selected item

from the source ListBox if the user holds down the

left mouse button and moves the pointer more than

8 pixels. This gives users a little leeway before the

cursor changes, but you could set the

DragThreshold property to and number you wish.

So that’s it for the Source.. .only three methods and

very little code!

The Drag-and-Drop Target(s)

Targets are even easier.. .there are only two meth-

ods in each target that need our attention.

1.

The DragOver method should look like this:

(Con't, page 6)

Page 5