One of the features of our Access JumpStart application template is a form resizing class:

This VBA class, HAL_FormResizeCls, is designed to handle the resizing of forms and their controls in Microsoft Access. Here’s a summary of its functionality and how it works:

Purpose

The class processes form resizing, ensuring that controls on the form are rescaled and repositioned appropriately when the form size changes. This is particularly useful for maintaining a consistent layout and appearance across different screen sizes and resolutions.

Key Components

1. Enums and Constants:
   • CtlPositionTag: Enum for storing/retrieving control positioning data.
   • frScaleMode: Enum for different scaling modes (automatic by width, automatic by height, fixed).
   • Constants like FrmHeightMax and FrmWidthMax define the maximum dimensions for the form.
2. Properties:
   • DebugON: Controls whether debug messages are printed.
   • FixedScale: Sets or gets the fixed scaling factor.
   • TimedResize: Enables or disables timed resizing.
   • TimerInterval: Sets or gets the timer interval for resizing.
   • DefaultAspectRatio: Sets or gets the default aspect ratio.
   • ScaleType: Sets or gets the current scaling mode.
   • DoSubForms: Enables or disables scaling for subforms.
   • ResizeInProgress: Indicates if a resize operation is in progress.
3. Methods:
   • SaveControlPositions: Saves the original positions and sizes of controls.
   • RescaleControlPositions: Main method to rescale controls based on the current scaling mode.
   • SetSizeOptions: Toggles through different resize scale-set algorithms.
   • TimerEvent: Handles the timer event for resizing.
   • RescaleControlPositions_Main: Core logic for rescaling controls on the main form.
   • RescaleControlPositions_Sub: Handles rescaling for subforms.
   • RescaleControlsOnForm: Rescales and repositions each control on the form.

How It Works

1. Initialization:
   • The class is initialized with default properties, such as enabling the timer switch, setting the timer interval, and defining the default aspect ratio.
2. Saving Control Positions:
   • SaveControlPositions method is called to store the original positions and sizes of all controls on the form. This information is saved in the Tag property of each control.
3. Rescaling Controls:
   • When the form is resized, the RescaleControlPositions method is triggered. If timed resizing is enabled, it sets a timer to delay the actual resizing.
   • The RescaleControlPositions_Main method calculates the new scaling factor based on the current scaling mode and resizes the form and its controls accordingly.
   • The RescaleControlsOnForm method iterates through each control, adjusting its size and position based on the scaling factor.
4. Handling Subforms:
   • If subform scaling is enabled, the RescaleControlPositions_Sub method is called recursively to rescale controls within subforms.
5. Debugging and Error Handling:
   • The class includes debug messages and error handling to assist with troubleshooting and ensure smooth operation.

Currently Known Issues:

Controls That Might Not Work Well

1. Custom ActiveX Controls:
   • Custom ActiveX controls or third-party controls might not respond correctly to the resizing logic, as they may have unique properties or behaviors that aren’t accounted for in the class.
2. Bound Object Frames:
   • Controls like Bound Object Frames, which display OLE objects, might not resize properly because their content can vary significantly in size and aspect ratio.
3. Charts and Graphs:
   • Microsoft Access charts and graphs can be complex to resize dynamically, especially if they have detailed formatting or data-bound properties.
4. Web Browser Controls:
   • Web Browser controls might not resize as expected due to their dependency on external content and rendering engines.
5. Subreports:
   • While the class handles subforms, subreports might not be resized correctly, especially if they are embedded within other controls or have complex layouts.

Scenarios That Might Cause Issues

1. Nested Controls:
   • Controls nested within other controls (e.g., a control within a tab control) might not resize correctly if the parent control’s resizing logic isn’t properly handled.
2. Conditional Formatting:
   • Controls with extensive conditional formatting or dynamic visibility settings might not resize as expected, as the class might not account for all possible states.
3. Complex Layouts:
   • Forms with very complex layouts, including multiple sections and overlapping controls, might experience issues with resizing and repositioning.
4. VBA Code using the Tag property of controls:
   • Forms with existing VBA code using the Tag property of controls will conflict with the current version of this class.