Detect when Combo() opened

[zMidair]

Version/Branch of Dear ImGui:

Version 1.90

Back-ends:

n/a

Compiler, OS:

Windows 11 + MSVC 2022

Full config/build information:

No response

Details:

How can I detect when a Combo() is opened?

Hello, by opened I mean when its clicked and its items are shown.

Screenshots/Video:

No response

Minimal, Complete and Verifiable Example code:

if (ImGui::Combo("Clickpack", &clickpack.selectedClickpack, clickpack.clickpackList.data(), clickpack.clickpackList.size())) 
{}

[GamingMinds-DanielC]

If you can rework your call to Combo() to a BeginCombo() / EndCombo() pair, the combo is open if BeginCombo() returns true. You would then have to submit your items yourself, but you can look at the Combo() implementation for how to do that.

If you want to keep using the more compact Combo() function, you can calculate the popup id with ImHashStr("##ComboPopup", 0, GetItemID()) and check if that popup is currently open.

[ocornut]

How can I detect when a Combo() is opened?

It's also worth explaining why you need this, as this might be a XY Problem question.

[zMidair]

How can I detect when a Combo() is opened?

It's also worth explaining why you need this, as this might be a XY Problem question.

I need this since im using the Combo to choose a file in a folder and I want to update the list when the Combo is opened.

[zMidair]

If you can rework your call to Combo() to a BeginCombo() / EndCombo() pair, the combo is open if BeginCombo() returns true. You would then have to submit your items yourself, but you can look at the Combo() implementation for how to do that.

If you want to keep using the more compact Combo() function, you can calculate the popup id with ImHashStr("##ComboPopup", 0, GetItemID()) and check if that popup is currently open.

Can you give me an example?

[ocornut]

I need this since im using the Combo to choose a file in a folder and I want to update the list when the Combo is opened.

Then you should use if (ImGui::IsWindowAppearing())

[GamingMinds-DanielC]

Can you give me an example?

As I said, you can look at the implementation of Combo() for an example of how to use those functions. After all, that is just a wrapper for the step by step approach. Here is the exact place:
https://github.com/ocornut/imgui/blob/master/imgui_widgets.cpp#L1951-L1978

As Omar hinted at, you can use IsWindowAppearing() to test if a window has just been opened. Right after BeginCombo() returns true is the best place for that, then you are testing if the opened popup is just appearing.

[zMidair]

I need this since im using the Combo to choose a file in a folder and I want to update the list when the Combo is opened.

Then you should use if (ImGui::IsWindowAppearing())

Doesnt it need a parameter? Or where should I put it? Before or after the Combo is created

[zMidair]

Can you give me an example?

As I said, you can look at the implementation of Combo() for an example of how to use those functions. After all, that is just a wrapper for the step by step approach. Here is the exact place: https://github.com/ocornut/imgui/blob/master/imgui_widgets.cpp#L1951-L1978

As Omar hinted at, you can use IsWindowAppearing() to test if a window has just been opened. Right after BeginCombo() returns true is the best place for that, then you are testing if the opened popup is just appearing.

Alr thanks, I will try this