I have requirement to compare the same property in pagelist , and need to populate a error message if duplicate exists.
I have checked the out of box functionality which is present "pyremoveduplicateproperties" but I don't want to remove duplicate values and my requirement is to just inform the end user that there is error in the respective field.
You could use the countInPageList function to see how many entries already exist in the page list. The IsInPageList function could work as well if you only need to check if the value already exists and not how many times.
I find the solution by using the method "countInPageList" Method in different way, as I assign the each value of the property to a local variable in a loop and use the method "countInPageList" as if Count is greater than 1 and it's working fine,