Mega Code Archive
Easy (none temp var required) way of discovering changes
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Title: easy (none temp var required) way of discovering changes
Question: Is there an easy way to know if a form's textboxes has been modified ?
Answer:
When writing normal UI-applications you often want to know weather the text-controls on the form has been changed or not since the form showed up in front of the user...
a very simple way is to use two recursive functions (like the onec below) for this purpose. They will loop thru the entire form and check if any TEdit-kind of VCL has been modified!
What you need to do i to call Modify(myForm, false); from the from's OnShow-event. This will set all TEdits as NOT modified but as fast as the user changes one it will automatically set modified to true.
In your forms OnClose-event you attach the "if IsModified(myForm) then ..." code (normally you then wish to save the data, or perhaps do the ms-thingy and ask the user a couple of times wheater he really want to loose the changes or not =)....
This solution wont handle any other standard VCL's then the once _below_ TEdit (TMemo, TRichEdit..) so you must still figure out a way keep track on your CheckBox'es etc but atleast this will make it a little bit easier =)
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function IsModified(Parent: TWinControl) : Boolean;
var i : integer;
begin
for i := 0 to Parent.ControlCount-1 do
if (Parent.Controls[i] is TEdit) then
begin
if TEdit(Parent.Controls[i]).Modified then
begin
result := true;
exit;
end;
end
else
if Parent.Controls[i] is TWinControl then
begin
result := IsModified(TWinControl(Parent.Controls[i]));
if result then exit;
end;
result := false;
end;
procedure Modify(Parent: TWinControl; Value: boolean);
var i : integer;
begin
for i := 0 to Parent.ControlCount-1 do
if Parent.Controls[i] is TEdit then TEdit(Parent.Controls[i]).Modified := Value
else if Parent.Controls[i] is TWinControl then
Modify(TWinControl(Parent.Controls[i]), value);
end;
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