TPlannerCalendar is a highly configurable, non-database-aware calendar component from the TMS VCL UI Pack designed for Delphi and C++ Builder. It is used to present, interact with, and color-code dynamic multi-event scheduling interfaces.
When building dynamic schedules, the TPlannerCalendar component excels at visually flagging deadlines, managing multi-date selections, and custom-rendering schedule data. 📅 Core Structural Options
To begin building your schedule, choose the design architecture that fits your app context:
TPlannerCalendar: Best for manual event arrays and internal custom scheduling logics.
TDBPlannerCalendar: Automatically displays, inserts, and syncs schedule events directly from a data source.
TPlannerCalendarGroup: Stacks multiple monthly displays together to show long-term operational schedules side-by-side. 🛠️ Building the Dynamic Event Array
Unlike a generic TPlanner timeline, TPlannerCalendar tracks dynamic schedules using PlannerCalendar.Events. Rather than rebuilding objects from your event handlers on every navigation change, instantiate event flags in memory once and pass dates dynamically:
var NewEvent: TPlannerEvent; begin PlannerCalendar1.BeginUpdate; try NewEvent := PlannerCalendar1.Events.Add; NewEvent.Date := EncodeDate(2026, 6, 15); // Dynamic target date NewEvent.Color := clWebOrange; // Theme category color NewEvent.Shape := evsCircle; // UI marker style (evsSquare, evsTriangle) finally PlannerCalendar1.EndUpdate; end; end; Use code with caution. 🎨 Live UI Updates via Events
To adapt your scheduling UI to shifting task types, priorities, or structural restrictions on-the-fly, leverage component event hooks: 1. Modify Data Live with OnGetEventProp
Instead of mutating the permanent scheduling database structure, use this event to alter event appearances (like highlighting an urgent milestone dynamically) during visual render cycles. 2. Handle Insert Customizations via OnEventInsert
When building bound database schedules using TDBPlannerCalendar, intercept new inputs to assign initial visual presets automatically:
procedure TForm1.DBPlannerCalendar1EventInsert(Sender: TObject; Event: TPlannerEvent); begin // Highlight newly inserted employee holiday inputs dynamically Event.Color := clSkyBlue; end; Use code with caution. 3. Custom Rendering inside OnCellDraw
To draw distinct visual elements, lines, text blocks, or metrics inside individual cell matrices, use OnCellDraw:
procedure TForm1.PlannerCalendar1CellDraw(Sender: TObject; Canvas: TCanvas; Day: TDate; Selected, Marked, InMonth: Boolean; Rect: TRect); var DayText: string; begin // Check if cell is the active system time if Day = Int(Now) then begin Canvas.Brush.Color := clYellow; Canvas.Rectangle(Rect); // Paint highlight box end; // Custom font formatting for alternate days DayText := IntToStr(CurrentDayValue); if Odd(CurrentDayValue) then Canvas.Font.Style := [fsBold]; DrawText(Canvas.Handle, PChar(DayText), Length(DayText), Rect, DT_CENTER or DT_VCENTER); end; Use code with caution. ⚡ Troubleshooting Common Pitfalls
Canvas Access Violations in Form Creation: If the object processes layout tracking strings or mouse tracking parameters before a formal paint step initializes, memory exceptions can happen. Avoid this by calling a hard-forced paint routine inside your startup initialization block:
PlannerCalendar1.BeginUpdate; PlannerCalendar1.Paint; // Instantly safe-initializes the hidden FCanvas variable PlannerCalendar1.EndUpdate; Use code with caution.
Streaming Failures in Custom Frames: Dropping a TPlannerDatePicker (which encapsulates a TPlannerCalendar) straight onto a reusable TFrame layout can cause streaming issues. Work around this by explicitly instantiating your calendar components via runtime code inside the frame instead of visually nesting them in the IDE designer.
If you are developing a specific layout, feel free to share:
Are you binding to a database backend (TDBPlannerCalendar) or managing dates in an internal memory matrix?
Do users need to make non-contiguous date selections (e.g., cherry-picking odd days)?
Are you pairing it with a timeline layout component, like TPlanner? TMS VCL UI Pack – TPlannerRangeSelector
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