Can the max column/row number be changed?

[Mitchell]

At the current max of "4", I cannot create a strip of 6 or more months (for example). Is there a workaround for showing more than 4 columns/rows, or is there some technical issue in doing so?

Thanks - Mitch

[Mitchell]

Using Decompile, I noticed that while RadCalendar has const values defined for max columns and rows, those const values are never used. Instead, the PropertyMetaData for the Columns property specifies a method to coerce the columns/rows to be between 1 and 4 (hardcoded). So, I was able to derive from RadCalendar, and call OverrideMetadata() to provide different metadata for the Columns property. I had to use reflection to make sure that the base class's OnColumnsChanged method was called.  If put my derived class into the xaml of my simple example project (and make sure I have a style based on the style used for RadCalendar), I can specify 6 columns & get:



Yeah, it works! But, have I created the potential for some problems (aside from a possible upgrade issue from using reflection to call a private method)?  

Thanks - Mitch

My little derived class is:

public class RadCalendarEx : RadCalendar
    {

        public RadCalendarEx()
            : base()
        {
        }

        static RadCalendarEx()
        {
            System.Runtime.CompilerServices.RuntimeHelpers.RunClassConstructor(typeof(RadCalendar).TypeHandle);

            RadCalendar.ColumnsProperty.OverrideMetadata(typeof(RadCalendarEx),
                new System.Windows.PropertyMetadata((object)1, new System.Windows.PropertyChangedCallback(RadCalendarEx.OnColumnsChangedEx),
                    new CoerceValueCallback(RadCalendarEx.CoerceColumns)));

        }

        private void OnColumnsChangedEx()
        {
            //Call private handler in the RadCalendar class.
            MethodInfo mi = typeof(RadCalendar).GetMethod("OnColumnsChanged", BindingFlags.NonPublic | BindingFlags.Instance);
            if (mi != null)
            {
                mi.Invoke(this, null);
            }
        }

        private static void OnColumnsChangedEx(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            ((RadCalendarEx)sender).OnColumnsChangedEx();
        }

        private static object CoerceColumns(DependencyObject sender, object value)
        {
            //int num = Math.Min(4, (int)value);
            //return Math.Max(1, num);

            return value;
        }
    }

[Mitchell]

Hmm, my screenshot didn't get saved in my previous post. Trying again...

[Mitchell]

Screenshot still not saving with my post. Attaching now instead...

[Nasko]

Hello Mitchell,

We have checked the provided code snippet and it seems that the approach you've used works fine. However, please notice that this is not a supported and there isn't any guarantee that it won't cause some unexpected behavior of RadCalendar.

Please, do not hesitate to contact us if you have any additional questions concerning Telerik controls.

Regards,
Nasko
Telerik

 

 

[Mitchell]

Excellent. Yes, I understand and agree completely with the warning since the code is based on internal implementation details. But if there is no known big gotcha for why the number 4 was chosen, it is easier to weigh that risk vs getting more than 4 columns/rows.  Thanks for the info!