ComboBox with MaxDropDownItems property

  • Thread starter Thread starter Paul Stork
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Paul Stork

Does anyone know of a 3rd party combobox control that implements the
MaxDropDownItems property from regular Visual Studio in the Compact
Framework version of a combo box? I've got a working copy that I build
myself based on the User Drawn List code available from opennetcf.org. But
I've still got one problem. The app I want to use it in uses Panels and
although the regular Combobox will display across a Panel boundary when
dropped down my rendition of the owner drawn list won't. I'm sure its a
problem with which GDI handle is being used for the dropdown, but I can't
seem to get around it. I've searched the web, but can't find any custom
control that handles them maxdropdownitems property.

Can anyone point me in the right direction.

Paul Stork
(e-mail address removed)
 
I guess, the dropdown portion of your control can't be a
child of a panel, so you can try to make it a child of a
form instead and bring it to the top z-order by calling
Control.BringToTop when showing this dropdown.

HTH... Alex
 
Thanks Alex,
I've tried changing the control to make the dropdown portion of the ComboBox
a child of the panel's parent(ie the form) instead of the panel itself, but
I've hit a mental block and can't seem to get it to work. I was hoping
someone else might have already developed a ComboBox with the extra property
I want. If not, I guess I'll either keep plugging away at it or try to
figure out how to change the project design to get away from using panels.

Paul Stork
(e-mail address removed)
 
Could you guys describe the scenario where you want to control the number
of items displayed in the drop down list? Maybe I could run it past the
developers as a feature request.




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I doubt this is an issue that affects a lot of people, it's a fairly
specific usage. I've been doing a lot of programming for researchers who
wish to use PDAs to distribute survey forms to subjects. When a question
requires more than about 8 answers it is inefficient to code it as a set of
radio buttons due to screen space. A Combobox with a dropdown can put more
individual choices in a smaller area. The problem is that its poor research
design not to display all the choices at once since the subject might be
influenced to answer from what is displayed rather than scrolling. So we
need to display all choices as soon as the subject drops down the list.
Since the CF combobox is limited to displaying a max of 8 items this is a
problem.

I've created an owner drawn list that has the capability I need. The
problem is that multiple panels are used in the application to simplify
formatting multiple questions on a page. Each question is dynamically
placed on a panel and the panels are stacked top to bottom until the screeen
limit is reached. When a question with my custom combobox is placed on a
panel the drop down is also restricted to the boundaries of the panel. To
display a long list the dropdown needs to overlap other questions displayed
below or above it.

That means I have 3 options. I either need to redesign the original use of
panels in the application, redesign the custom combobox to use a different
graphic space for the dropdown list, or find someone who has already created
this functionality in a 3rd party control. Either 1 or 2 will mean a lot of
work and redesign. Hence my request for #3.

Paul Stork
(e-mail address removed)
 
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