Grouping by Custom Object

[Dylan]

Assuming "Date" is of type DateTime, I know it's possible to do the following:

<telerik:GridGroupByExpression>
     <SelectFields>
         <telerik:GridGroupByField FieldName="Date" />
     </SelectFields>
     <GroupByFields>
         <telerik:GridGroupByField FieldName="Date" SortOrder="Ascending" />
     </GroupByFields>
 </telerik:GridGroupByExpression>

I've replaced my DateTime property with a new custom class called MonthAndYear.

[Serializable]
protected class MonthAndYear : IComparable<MonthAndYear>
{
    public int Month { get; set; }
    public int Year { get; set; }

    public string monthString
    {
        get
        {
            return CultureInfo.CurrentCulture.DateTimeFormat.GetMonthName(Month);
        }
    }

    public MonthAndYear(int month, int year)
    {
        Month = month;
        Year = year;
    }

    public MonthAndYear(DateTime dateTime)
    {
        Month = dateTime.Month;
        Year = dateTime.Year;
    }

    public static MonthAndYear Now
    {
        get
        {
            return new MonthAndYear(DateTime.Now.Month, DateTime.Now.Year);
        }
    }

    public static MonthAndYear FromDate(DateTime date)
    {
        return new MonthAndYear(date.Month, date.Year);
    }

    public MonthAndYear AddMonths(int num)
    {
        DateTime tempDate = new DateTime(Year, Month, 1);
        tempDate = tempDate.AddMonths(num);
        return new MonthAndYear(tempDate.Month, tempDate.Year);
    }

    public MonthAndYear AddYears(int num)
    {
        int newYear = Year + num;
        return new MonthAndYear(Month, newYear);
    }

    public static bool operator >(MonthAndYear a, MonthAndYear b)
    {
        if (a.Year == b.Year)
            return a.Month > b.Month;
        else if (a.Year > b.Year)
            return true;
        else
            return false;
    }

    public static bool operator <(MonthAndYear a, MonthAndYear b)
    {
        if (a.Year == b.Year)
            return a.Month < b.Month;
        else if (a.Year < b.Year)
            return true;
        else
            return false;
    }

    public static bool operator >=(MonthAndYear a, MonthAndYear b)
    {
        return a > b || a == b;
    }

    public static bool operator <=(MonthAndYear a, MonthAndYear b)
    {
        return a < b || a == b;
    }

    public static bool operator ==(MonthAndYear a, MonthAndYear b)
    {
        return a.Month == b.Month && a.Year == b.Year;
    }

    public static bool operator !=(MonthAndYear a, MonthAndYear b)
    {
        return !(a.Month == b.Month && a.Year == b.Year);
    }

    public override bool Equals(object obj)
    {
        if (obj == null)
        {
            return false;
        }
        MonthAndYear m = obj as MonthAndYear;
        if ((System.Object)m == null)
        {
            return false;
        }

        return this.Month == m.Month && this.Year == m.Year;;
    }

    public override string ToString()
    {
        return new DateTime(Year, Month, 1).ToString();
    }

    public override int GetHashCode()
    {
        int hash = 23;
        hash = hash * 31 + Month.GetHashCode();
        hash = hash * 31 + Year.GetHashCode();
        return hash;
    }

    public int CompareTo(MonthAndYear other)
    {
        if (this < other) return -1;
        if (this == other) return 0;
        return 1;
    }
}

Now when I try to group by Date, I get an IndexOutOfRange exception that says "Cannot find column Date." If I remove the GridGroupByExpression, everything works just fine minus the fact that my data isn't grouped by Date. Is there a way to use custom objects in RadGrid's grouping functionality? Or at least a way to mimic grouping by DateTime?   

[Konstantin Dikov]

Hi Dylan,

After some testing on my end I was able to replicate the described issue.

I will log this in our system, so our developers team could investigate it further in order to determine if this is a bug or a limitation with RadGrid grouping.

Regarding your question for grouping by DateTime object, this is a supported scenario and you should not experience any issues with it.

Please excuse us for any inconvenience caused by this.


Regards,
Konstantin Dikov
Telerik