No, you can't. Only "cheat" ways like your.
E.g.
bool multiline = label.Height - label.Padding.Top - label.Padding.Bottom > label.Font.Size*2;
Вопрос
I want to detect a text in my label is single or multiline. Can I do it in a more plain way than
TextRenderer.MeasureText(label.Text, font, label.Size).Height > TextRenderer.MeasureText("a", font).Height
Решение
No, you can't. Only "cheat" ways like your.
E.g.
bool multiline = label.Height - label.Padding.Top - label.Padding.Bottom > label.Font.Size*2;