Added Combobox.Delete() and Listbox.Delete() and added some TODOs.

combobox.go

@@ -53,7 +53,17 @@ func (c *Combobox) InsertBefore(what string, before int) (err error) {
 	return nil
 }
 
-// TODO Delete
+// Delete removes the given item from the Combobox.
+func (c *Combobox) Delete(index int) error {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	if c.created {
+		return c.sysData.delete(index)
+	}
+	c.initItems = append(c.initItems[:index], c.initItems[index + 1:]...)
+	return nil
+}
 
 // Selection returns the current selection.
 func (c *Combobox) Selection() string {

listbox.go

@@ -53,6 +53,18 @@ func (l *Listbox) InsertBefore(what string, before int) (err error) {
 	return nil
 }
 
+// Delete removes the given item from the Listbox.
+func (l *Listbox) Delete(index int) error {
+	l.lock.Lock()
+	defer l.lock.Unlock()
+
+	if l.created {
+		return l.sysData.delete(index)
+	}
+	l.initItems = append(l.initItems[:index], l.initItems[index + 1:]...)
+	return nil
+}
+
 // TODO Selection
 
 // TODO SelectedIndices

main.go

@@ -9,12 +9,14 @@ func main() {
 	w := NewWindow("Main Window", 320, 240)
 	w.Closing = make(chan struct{})
 	b := NewButton("Click Me")
+	b2 := NewButton("Or Me")
+	s2 := NewStack(Horizontal, b, b2)
 	c := NewCheckbox("Check Me")
 	cb1 := NewCombobox(true, "You can edit me!", "Yes you can!", "Yes you will!")
 	cb2 := NewCombobox(false, "You can't edit me!", "No you can't!", "No you won't!")
 	e := NewLineEdit("Enter text here too")
 	l := NewLabel("This is a label")
-	s0 := NewStack(Vertical, b, c, cb1, cb2, e, l)
+	s0 := NewStack(Vertical, s2, c, cb1, cb2, e, l)
 	lb := NewListbox(true, "Select One", "Or More", "To Continue")
 	lb2 := NewListbox(false, "Select", "Only", "One", "Please")
 	i := 0
@@ -48,6 +50,11 @@ mainloop:
 				panic(err)
 			}
 			doAdjustments()
+		case <-b2.Clicked:
+			cb1.Delete(1)
+			cb2.Delete(2)
+			lb.Delete(3)
+			lb2.Delete(4)
 		}
 	}
 	w.Hide()

sysdata.go

@@ -51,6 +51,9 @@ func (c *cSysData) selectedTexts() []string {
 func (c *cSysData) setWindowSize(int, int) error {
 	panic(runtime.GOOS + " sysData does not define setWindowSize()")
 }
+func (c *cSysData) delete(int) error {
+	panic(runtime.GOOS + " sysData does not define delete()")
+}
 
 const (
 	c_window = iota

sysdata_windows.go

@@ -467,3 +467,23 @@ func (s *sysData) setWindowSize(width int, height int) error {
 	}
 	return nil
 }
+
+func (s *sysData) delete(index int) (err error) {
+	ret := make(chan uiret)
+	defer close(ret)
+	uitask <- &uimsg{
+		call:		_sendMessage,
+		p:		[]uintptr{
+			uintptr(s.hwnd),
+			uintptr(classTypes[s.ctype].deleteMsg),
+			uintptr(_WPARAM(index)),
+			uintptr(0),
+		},
+		ret:		ret,
+	}
+	r := <-ret
+	if r.ret == uintptr(classTypes[s.ctype].selectedIndexErr) {
+		return fmt.Errorf("failed to delete item from combobox/listbox (last error: %v)", r.err)
+	}
+	return nil
+}

todo.md

@@ -17,6 +17,7 @@ so I don't forget:
 - Combobox/Listbox.DeleteAll
 - Combobox/Listbox.Select (with Listbox.Select allowing bulk)
 - Listbox.SelectAll
+- have Combobox.InsertBefore, Listbox.InsertBefore, Combobox.Delete, and Listbox.Delete return an error on invalid index
 
 super ultra important things:
 - the windows build appears to be unstable: