I suspect the issue here should be caused by the source.
What is the Tableau1_2 contains?
This table in lookup function should be the LunchType table, which is the second data source added into PowerApp.
The following si the lookup function reference:
I just added the TextBox under the Lunch form, then change the Text formula with the lookup function, this works from my side.
The first parameter of lookup used here is the lunchtype table, second part is lunchtype column name in lunchtype table equal to the selected value of lunchname dropdown, thrid parameter is another column newly added into lunchtype table, as the output value of lookup function.
You may take a try to manually input the parameters, check to see if this would make it work.
I recreate completely the app since beginning and now, i got a different error message :
I translate the error message for you : "This rule creates a circular reference between the properties, which is not allowed. A property can not refer itself or reference other properties affected by its value"
Thanks for helping,
Few things that you could take a try.
First, Leave the original TextInput Box, Add the Dropdown box and change the Update and Y properties of the Lunch Card as before,
Then Modify the Textinput box Default formula with the lookup formula:
Check your PowerApp Studio version, make sure the version is 2.0.542. If not, update your PowerApp Studio.
If issue still insists, duplicate your Lunchtype Excel in OneDrive for business, rename the lunchtype column to Lunchtype1, add this Excel as another data source, then modify the lookup formula to the one below:
If still not working, please share the detailed steps that you have tried to create your app.
What is your current situation?
If any further help needed, please post back.
I work on it, the problem was the wrong name of value, it was my fault but now all is ok.
All option work (time, comment, ingredient and i add the price)
Now I can show it to my colleagues and especially the live test.
Thanks for all the support and reply you did for me.
I need your help again.
The App is ok but now i want to share it with my collegeas. I follow the step of Powerapps for shared the application, i test with myself on my smartphone it works well.
Then i ask to one of my collegeas to test it for me and he got a error message at app launcher :
The datasource can't be dowloaded. However i put on my folder where the database are stored the good rights to access to this ressource.