ICursor.set_Value NotImplementedException?

[JohnStephens]

I have some code that I am updating.  Originally, I was just reading the data with the 'get_Value' method, but I am now trying to change the data with 'set_Value'.  However, when I call the 'set_Value' method I get a "NotImplementedException" which makes absolutely no sense to me. 

ICursor cur = joinTable.Search(qf, false);
using (ComReleaser comReleaser = new ComReleaser())
   {
      comReleaser.ManageLifetime(cur);

      IRow row = null; 
      while ((row = cur.NextRow()) != null)
      {
          //do some stuff
          row.set_Value(row.Fields.FindField(myFieldName), myValue); 
          cur.UpdateRow(row);
      }
   }

So that throws the exception.  It's pretty similar to the code under "Using an update cursor" here.

Also, I change the cursor to "ICursor cur = joinTable.Update(qf, false);" I get the exception at that line. 

Any ideas or words on the problem would be appreciated.

[NeilClemmons]

I'm guessing that joinTable is the result of a table join?  If so, I'm pretty sure you can't edit that.  At least that's how it used to be -you could only edit the original featureclasses/tables.

[JohnStephens]

I'm guessing that joinTable is the result of a table join?  If so, I'm pretty sure you can't edit that.  At least that's how it used to be -you could only edit the original featureclasses/tables.

That's a real pain in the butt if it's true.