Filtering in SharePoint 2007 using [Today] and a String field

Question

I have a C# application that inserts data weekly from a CSV flat file to a SharePoint list with over 30000 records in it and growing.

Management wants to see only the items that are under 90 days old in a view, but the date field is being inserted as a single line of text (otherwise it won't upload at all). Right now I have tried creating a new calculated column using =TEXT(DateField,"yyyymmdd") and setting that field to a DateTime type. I then tried to filter on that new column in the view using "NewColumn Greater Than [Today]-90" but that returns zero results.

Is there a way to convert my text field into a date field that can be used to filter like this, or perhaps a way to convert the flat file string into a DateTime value before I even upload to SharePoint?

Answer 1

I ended up finding an answer.

SharePoint would not let me filter on fields that were converted in this way, so I had to upload the data already in the correct format. The CSV feed was giving me a string in the "yyyyMMdd" format, but SharePoint needs hyphens between the format blocks like: "yyyy-MM-dd". The FieldRef node inside your batch element also needs to look like this:

"<Field Name='Date_x0020_Field' Type='DateTime' Format='DateOnly'>" + date + "</Field>"

I ended up converting to a DateTime object and then back to string, because I was integrating some other data already in a datetime format, but you could just as easily insert the hyphens manually.

You can convert a string to DateTime with Convert.ToDateTime(stringDate); and you can convert to the proper format from that using dateTimeObject.ToString("yyyy-MM-dd");