I have below code where I get full set of file names and for all the file names I need to set the in_progress_flag =1 . Which is done by calling a stored proc.
The Output of Get Valid Entity is like below
{
"count": 2,
"value": [
{
"Entity_Name": "Member",
"File_Name": "MemberPARQUET"
},
{
"Entity_Name": "Dealer_Group",
"File_Name": "Dealer_Group.PARQUET"
}
]}
The Stored Procedure is having parameter, which will take file_name from the lookup to update its status to 1.
Currently I am using like below
@activity('Get Valid Entity Names').output.File_Name
Which is failing with error "The expression 'activity('Get Valid Entity Names').output.File_Name' cannot be evaluated because property 'File_Name' doesn't exist, available properties are 'count, value, effectiveIntegrationRuntime, billingReference, durationInQueue'.",
Any help on how to call a value from Lookup into a parameter please

The error you are getting because lookup output does not contain
File_Nameattribute directly its under the value array so to access it you need to use expression like below:As value is an array above expression will fetch the filename from 0 the index element from value array.
If you want to iterate on each filename take Foreach activity and pass the expression for items as
and then under Foreach take your store procedure activity and iterate on each file using
@item().File_Name