Sort by modified date in custom search core results webpart

Question

I have created a custom search results web part which implements some simple sorting, for example i have this piece of code which allows me to sort it desc/asc by title:

    CoreResultsDatasource dataSource = this.DataSource as CoreResultsDatasource;

    if (!string.IsNullOrEmpty(OrderByProperty))
    {
       // change the sortorder
       dataSource.SortOrder.Clear();
       dataSource.SortOrder.Add(OrderByProperty, SortDirection);
    }

Basically it works for the title, but when i want to sort by Modified Date, it doesnt work, i get an error in the webapart:

Property doesn't exist or is used in a manner inconsistent with schema settings.

I did try to add it in: Core Search Results Display Metadata => Properties

But still nothing happens.

Any idea how can i do it?

PS: I tried to pass "ModifiedDate" and i tried to pass "LastModifiedTime" Another strange issue i notice is that when i pass a title outside of search center it breaks i get an "Internal error" no errors in the log.

Answer 1

you can only provide sorting on managed properties. Look for the exact name of the managed property in central administration. I have similar web part and it works for me. Maybe look if the crawled property is correctly assigned to managed property.