Solved! Go to Solution.
Finally I found the solution, The issue was the control, I was using the combobox from SharePoint by default, so I change the control to the DropDownControl, but after that I need to refresh the data source of the DataCard because It was losed when I change the Control, so the Combobox doesn't support the formula UpdateContext, It working fine with DropDown.
Thank you to all people that help me.
God Bless you!
You can do this using the Dropdowns Default property.
For example, Set the OnSelect propery for the Buttons to be:
set the Dropdown default to be:
This will mean that whenever the button is pressed the value will change to the value entered and the dropdown will change to suit.
Just note that the Value you set DropdownDefault to need to be exactly as one of the options.
The Default Value for the Dropdown is looking for a Record rather than a Text value. This is usually the case if the sharepoint entry is a choise or a lookup
In this case you will need to set the defaut value to be a record