How to Create a Semi-Transparent Circular Control with Centered Text in C#?

Building a Customizable Transparent Circular Control with Text in C#

This guide details creating a circular control in C# with centered text, adjustable transparency, and dynamic resizing that avoids overlapping other form elements.

Challenge: Creating a circular control with text that automatically centers and resizes while maintaining transparency to avoid obscuring underlying controls.

Solution: A custom control addresses this by implementing several key features:

Step 1: Defining Control Properties

• Transparency Level: A property to control the background opacity.
• Inner Margin: Sets the spacing between the inner circle and the control's edge.
• Text Margin: Determines the spacing between the text and the inner circle.

Step 2: Enabling Transparency

• Override the CreateParams property to include the WS_EX_TRANSPARENT flag.
• Utilize ControlStyles.Opaque and ControlStyles.SupportsTransparentBackColor to prevent background painting and enable transparency.

Step 3: Dynamic Resizing and Text Positioning

• The OnPaint event handler dynamically calculates the circular area and centers the text based on the control's current dimensions.

Step 4: Implementing Custom Properties and Font Selection

• Public properties (InnerMargin, TextMargin) expose the custom settings.
• Employ a specified font (e.g., Segoe UI) and adjust baseline for precise text centering within the circle.

Step 5: Usage

• Add the custom control to your form from the Toolbox.
• Adjust the properties (size, transparency, margins) to fine-tune the control's appearance.

Key Improvements:

• Complete transparency is achievable, allowing for control overlap.
• Text remains perfectly centered within the circle regardless of size.
• The provided code is a template and may need adjustments for specific applications.

Note: This control is primarily for illustrative purposes and currently lacks a custom designer. Therefore, it functions as either fully transparent or completely opaque.

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