Why can't work with SharpGL?

Question

WPF

I decided to work with graphics using this library . Installed it via nuget. Done in code: using SharpGL;
It even works with some variables from the package:

double a = OpenGL.GL_TRIANGLES + 1; //данный код работает без ошибок

But when I copy the first line of code from the documentation, I get an error:

OpenGL gl = openGLCtrl1.OpenGL; //CS0103 Имя "openGLCtrl1" не существует в текущем контексте

I don't understand how to fix it

Answer 1

openGLCtrl1

Make sure you add a control with this name to the form