Checking to see if a column exists in a data reader [duplicate]

Is there a way to see if a field exists in an IDataReader-based object w/o just checking for an IndexOutOfRangeException?

In essence, I have a method that takes an IDataReader-based object and creates a strongly-typed list of the records. In 1 instance, one data reader has a field that others do not. I don't really want to rewrite all of the queries that feed this method to include some form of this field if I don't have to. The only way I have been able to figure out how to do it so far is to throw the 1 unique field into a try/catch block as shown below.

try
{
    tmp.OptionalField = reader["optionalfield"].ToString();
}
catch (IndexOutOfRangeException ex)
{
    //do nothing
}

Is there a cleaner way short of adding the "optional field" to the other queries or copying the loading method so 1 version uses the optional field and the other doesn't?

I'm in the 2.0 framework also.

I ended up finding a solution using the reader.GetName(int) method. I created the below method to encompass the logic.

public bool ColumnExists(IDataReader reader, string columnName)
{
    for (int i = 0; i < reader.FieldCount; i++)
    {
         if (reader.GetName(i).Equals(columnName, StringComparison.InvariantCultureIgnoreCase))
        {
            return true;
        }
    }

    return false;
}

The following will give you a list of the column name strings given a data reader. (Remember the results are based on the last read so it may not be the same depending on what the reader read).

var cols = reader.GetSchemaTable()
                 .Rows
                 .OfType<DataRow>()
                 .Select(row => row["ColumnName"]);

Or to check if a column exists:

public bool ColumnExists(IDataReader reader, string columnName)
{

  return reader.GetSchemaTable()
               .Rows
               .OfType<DataRow>()
               .Any(row => row["ColumnName"].ToString() == columnName);
}