The functionality you aim for seems quite specific and is not that straightforward to achieve through RadGridView. Basically, it depends more on your setup rather than the control as the GridViewRows represent each item of the bound collection. In your case, you can come up with a source that represents a month that has the days as items. Actually, the RadGridView might not be the most suitable control in your scenario. Though I am not familiar with your intentions, I suggest you check the RadScheduleView
controls as they might be more appropriate for your requirement.
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