Find the lowest and highest date from your data source
for example if you are using QVD as data source then use the below script to find the lowest and highest date value.
FROM your_QVD_Name.qvd (qvd);
Load min(DateField) as MinDate,
max(DateField) as MaxDate
Drop Table temp;
for SQL Server Use this Query.
SELECT Min(DateField) as MinDate from Your_Table_Name
SELECT Max(DateField) as MaxDate from Your_Table_Name
then go to the calendar oblect and set the Limit as per the below pick
Now the user not able to select any date out of the range from data source