@MiguelOliveira
Thanks for the method
But I'm really unfamiliar with power apps, I don't know where to use this function and send it back to sharepoint
I found some places to put the function
DataCardValue4 is my Combobox
Select : A B D
DataCardValue8 is my TextInput
Enter : E
I tried to use:
Concatenate(DataCardValue4.Selected, DataCardValue8.Text)
But it doesn't work, invalid arguments
And changed it to this
Concatenate(DataCardValue4.Selected.Value, DataCardValue8.Text)
Result output : AE,
It was close to what I wanted, but only one data was output
So I found another function
Concat(DataCardValue4.SelectedItems,DataCardValue8.Text,",")
Result output : E,E,E
No matter how I modify it, there will only be a bunch of blanks