Disabled in dropdown

This is confusing me! Why do you want to disable the field based on whether the selected value is null?

not based on the selected value. sometimes the field will be populated will a record is created and sometimes not. 

Can you share the code snippet of that dropdown?

disabled: {
if(
and(
a!isNullOrEmpty(
ri!record[] ),

local!isvalueavailable),
false,
true
),

},

Please share your code for the entire dropdown.  And as Stefan mentioned, please use a Code Box to enable us to see proper formatting and indentation.

a!dropdownField(
  label: "dropdown",
  choiceLabels: {},
  choiceValues: {},
  value: ri!record[fieldname],
  saveInto: ri!record[fieldname],
  disabled: {
    if(
      and(
        a!isNullOrEmpty(
          ri!record[],
          
        ),
        local!isValueAvailable
      ),
      false,
      true
    ),
    
  },
  required: true
)

Is that the real code? Line 11 does not look correct.

I didn;t mention the exact field here. But in my code I am referring to the dropdown field

OK. Then I need to repeat my question. Why do you make disabled depending on whether a value is selected?

OK. Then I need to repeat my question. Why do you make disabled depending on whether a value is selected?

My requirement here is, I pull the data from the external system. After pulling the data, when I view the record somteimes the dropdown field might get a value from the external system and sometimes it will be empty.
If the field is empty, then the user can select values from the dropdown. If the field is not empty (populated by the external system) then I want to disable the field, so that user can change the value