# EventInstance::setParameterValue not working.
**URL:** https://qa.fmod.com/t/eventinstance-setparametervalue-not-working/13111
**Category:** FMOD Engine
**Created:** [April 17, 2017, 8:52am UTC](https://qa.fmod.com/t/eventinstance-setparametervalue-not-working/13111 "2017-04-17T08:52:26Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@rtfc001](https://qa.fmod.com/u/rtfc001)
#### Post date: [April 17, 2017, 8:52am UTC](https://qa.fmod.com/t/eventinstance-setparametervalue-not-working/13111/1 "2017-04-17T08:52:26Z")
I hava Created an event in Fmod Studio like this:
1)prepare three music
2)there are three audio track,and three music has been added into track
3)add marker, tempo makrer,transition region for each track.
4)add a parameter named “demo” ,set it’s min value to 0,and max value to 30.
5)click the first and the second transition region and add a condition param which value is 0 up to 1,1.1 up to 2
6)prepare an application,put three buttons on it .the button one is used for starting play music. button two and button three are used for switching music.
In fmod studio,when i chang the “demo” param value,then the timeline cursor jump to the marker pointed by transition region immediately,and the music swiched gapless.
But in my code,there is no effective after i setted the parameter “demo” value in button click event function.my code like this:
```
void CFmodDemoDlg::OnBnClickedBtnFirst()
{
demoEventInstance->start();
studioSystem->update();
}
void CFmodDemoDlg::OnBnClickedBtnSecond()
{
FMOD_RESULT result;
result = demoEventInstance->setParameterValue("transcate", 0.5);
studioSystem->update();
result=demoEventInstance->triggerCue();
}
void CFmodDemoDlg::OnBnClickedBtnThird()
{
FMOD_RESULT result;
result=demoEventInstance->setParameterValue("transcate", 1.5);
studioSystem->update();
result=demoEventInstance->triggerCue();
}
```
it seems that only button three can play music after click it.
So,is there someone can help me ?
thousands of thanks.
---
### Author:  [@rtfc001](https://qa.fmod.com/u/rtfc001)
#### Post date: [April 17, 2017, 9:20am UTC](https://qa.fmod.com/t/eventinstance-setparametervalue-not-working/13111/2 "2017-04-17T09:20:51Z")
> [@](#):
>
> I hava Created an event in Fmod Studio like this:
> 1)prepare three music
> 2)there are three audio track,and three music has been added into track
> 3)add marker, tempo makrer,transition region for each track.
> 4)add a parameter named “demo” ,set it’s min value to 0,and max value to 30.
> 5)click the first and the second transition region and add a condition param which value is 0 up to 1,1.1 up to 2
> 6)prepare an application,put three buttons on it .the button one is used for starting play music. button two and button three are used for switching music.
>
> In fmod studio,when i chang the “demo” param value,then the timeline cursor jump to the marker pointed by transition region immediately,and the music swiched gapless.
>
> But in my code,there is no effective after i setted the parameter “demo” value in button click event function.my code like this:
>
> ```
> void CFmodDemoDlg::OnBnClickedBtnFirst()
> {
> demoEventInstance->start();
> studioSystem->update();
> }
>
> void CFmodDemoDlg::OnBnClickedBtnSecond()
> {
> FMOD_RESULT result;
> result = demoEventInstance->setParameterValue("transcate", 0.5);
> studioSystem->update();
> result=demoEventInstance->triggerCue();
> }
>
> void CFmodDemoDlg::OnBnClickedBtnThird()
> {
> FMOD_RESULT result;
> result=demoEventInstance->setParameterValue("transcate", 1.5);
> studioSystem->update();
> result=demoEventInstance->triggerCue();
> }
>
> ```
>
> it seems that only button three can play music after click it.
>
> So,is there someone can help me ?
> thousands of thanks.
It’s working,but i still don’t understand what happens