WinForms Events

Understanding Events in WinForms

WinForms uses an event-driven programming model that allows controls to respond to user actions such as clicks, key presses, and mouse movements. Each control exposes a set of events that you can handle in your code.

Commonly Used Events

Event	Description	Typical Use
Click	Occurs when the control is clicked.	Submit a form or trigger an action.
Load	Raised when the control is loaded.	Initialize data or UI elements.
Paint	Occurs when the control is redrawn.	Custom drawing.
KeyDown	Fires when a key is pressed while the control has focus.	Keyboard shortcuts.
TextChanged	Raised when the text property changes.	Validate input.
MouseEnter	Occurs when the mouse pointer enters the control's bounds.	Hover effects.

Subscribing to Events

You can subscribe to an event either in the designer or programmatically:

// Programmatic subscription
button1.Click += new EventHandler(Button1_Click);

private void Button1_Click(object sender, EventArgs e)
{
    MessageBox.Show("Button clicked!");
}

Best Practices

Keep event handlers short and focused.
Avoid long-running operations on the UI thread; use async patterns.
Detach event handlers when no longer needed to prevent memory leaks.
Use descriptive method names for event handlers.