Struct winsafe::gui::WindowModal[−][src]

pub struct WindowModal { /* fields omitted */ }

Expand description

An user modal window, which can handle events. Can be programmatically created or load a dialog resource from a .res file.

Implements Parent trait.

Implementations

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impl WindowModal

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pub fn new(parent: &dyn Parent, opts: WindowModalOpts) -> WindowModal

Instantiates a new WindowModal object, to be created with HWND::CreateWindowEx.

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pub fn new_dlg(parent: &dyn Parent, dialog_id: u16) -> WindowModal

Instantiates a new WindowModal object, to be loaded from a dialog resource with HWND::GetDlgItem.

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pub fn hwnd(&self) -> HWND

Returns the underlying handle for this control.

Note that the handle is initially null, receiving an actual value only after the control is created.

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pub fn on(&self) -> &WindowEvents

Exposes the window events.

Panics

Panics if the window is already created. Events must be set before window creation.

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pub fn run_ui_thread<F>(&self, func: F) where
F: FnOnce() -> BoxResult<()>,

If you perform a very long task in the UI thread, the UI freezes until the task is complete – this may cause the impression that your application crashed. That’s why long tasks are performed in parallel threads. However, at some point you’ll want to update the UI to reflect the task progress, but if you update the UI from another thread (different from the original UI thread), the UI may deadlock, and you application crashes.

The run_ui_thread method allows UI updates by running a closure synchronously in the window’s original UI thread.

This is what this run_ui_thread does, step-by-step:

blocks current thread;
switches to the window’s original UI thread;
runs the given FnOnce;
switches back to the first thread, which is then unblocked.

When working in a parallel thread, you must call run_ui_thread to update the UI.

Examples

The example below shows the event of a button click which starts a long task in a parallel thread. As it progresses, the status is printed at the windows’s titlebar.

use winsafe::{gui, BoxResult, GetCurrentThreadId, Sleep};

let wnd: gui::WindowMain; // initialized somewhere
let btn: gui::Button;

btn.on().bn_clicked({
    let wnd = wnd.clone();
    move || -> BoxResult<()> {
        println!("Click event at {:#x}", GetCurrentThreadId());

        std::thread::spawn({
            let wnd = wnd.clone();
            move || {
                println!("Parallel task starts at {:#x}", GetCurrentThreadId());
                Sleep(2000);

                wnd.run_ui_thread({
                    let wnd = wnd.clone();
                    move || -> BoxResult<()> {
                        println!("Updating UI at {:#x}", GetCurrentThreadId());
                        wnd.hwnd().SetWindowText("Status... 50%")?;
                        Ok(())
                    }
                });

                println!("Parallel task keeps going at {:#x}", GetCurrentThreadId());
                Sleep(2000);

                wnd.run_ui_thread({
                    let wnd = wnd.clone();
                    move || -> BoxResult<()> {
                        println!("Updating UI at {:#x}", GetCurrentThreadId());
                        wnd.hwnd().SetWindowText("Status... 100%")?;
                        Ok(())
                    }
                });
            }
        });

        Ok(())
    }
});