ComboBox Readonly Error
lazarus / 16-Databases

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Bartlebee · 2014-03-03 17:45

Lazarus v1.0.12

I am making an application that goes through the rows of a database as
you click the 'next' button.

One of my fields is an ID number that is shown in the comboBox. What I
liked was that the comboBox not only showed the user what ID number
they're currently on, but when you click to see the dropdown, it will
show you all the distinct id numbers in the table, and upon click take
you there. So it is a good filter.

Upon start, the comboBox shows the ID # of 1.1, and works as planned.
I recently decided that for my purposes I'd prefer a readonly comboBox
(basically a dropdown selectBox). But upon opening my app, the
comboBox shows nothing. I click 'next' and it is still blank. I do not
understand. In form create I set the combobox.text:=ID#, why is it
blank? (I did not have this problem when it wasn't readonly)

When I click once on the readonly comboBox it gives me all my choices
and highlights the ID I'm currently on (in this case 1.1) and the
program works 100% as planned. Works exactly as it used to. But first
I need to click on the readonly comboBox when I first start the
program.

I want, upon opening my program, for the comboBox to automatically
show the ID # without the need for the user to have to click on the
comboBox first. Suggestions?

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taazz · 2014-03-03 23:03

Code: [Select]comboBox1.ItemIndex := combobox1.Items.IndexOf(ID#);

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Bartlebee · 2014-03-04 20:11

Thank you taazz for the response. It seems to simplify some of my
code, but doesn't really address my problem. (at least not from what I
could see)

My problem is with the read-only combobox. If I set in the procedure
form create that combobox1.text:='blueberries'; and open the program,
I will see an empty combobox. I could make 'blueberries' the only item
in the combobox, and it would show up automatically in the regular
combobox but not in the readonly. (i'd have to click on the dropdown
and select it first. ) Is there anyway I can get the first item on the
dropdown to show automatically on the readonly combobox?

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mangakissa · 2014-03-04 21:47

What's a readonly combobox?
AFAIK the DBcombobox is set to a datafield of a dataset and the items
are manually filled in.
Another thing is a DBLookupcombox. Has the same functionality, read
its item from another table.
The keyfield will be found in the itemlist and show your item as text
and not an id.

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taazz · 2014-03-05 00:38

Quote from: Bartlebee on March 04, 2014, 09:11:36 pmThank you taazz
for the response. It seems to simplify some of my code, but doesn't
really address my problem. (at least not from what I could see)

My problem is with the read-only combobox. If I set in the procedure
form create that combobox1.text:='blueberries'; and open the program,
I will see an empty combobox. I could make 'blueberries' the only item
in the combobox, and it would show up automatically in the regular
combobox but not in the readonly. (i'd have to click on the dropdown
and select it first. ) Is there anyway I can get the first item on the
dropdown to show automatically on the readonly combobox?
Setting the itemindex property to the item you want selected should
select that item in the combobox if it is not then there is some other
problem. Please provide a minimalistic sample application that show
the problem for us to test, also make sure you use the latest lazarus
release for tests.

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engkin · 2014-03-05 03:40

Quote from: Bartlebee on March 04, 2014, 09:11:36 pmIs there anyway I
can get the first item on the dropdown to show automatically on the
readonly combobox?
Yes:
Code: [Select]  if ComboBox1.Items.Count > 0 then  //has some items?
    ComboBox1.ItemIndex := 0;       //show the first item   

To show blueberries:
Code: [Select]  ComboBox1.Items.Add('blueberries');  //add an item
  ComboBox1.ItemIndex := ComboBox1.Items.IndexOf('blueberries') ; 
//choose it