UnityEditor.ShaderUtil.GetPropertyCount C# (CSharp) Method

        public static extern int GetPropertyCount(Shader s);
        /// <summary>

        public override void OnGUI(Rect position, SerializedProperty prop, GUIContent content)
        {
            var att = (ShaderPropertyPopupAttribute)attribute;

            var directable = prop.serializedObject.targetObject as IDirectable;

            if (directable != null)
            {
                var actor = directable.actor;
                if (actor != null)
                {
                    var renderer = actor.GetComponent <Renderer>();
                    if (renderer != null)
                    {
                        var material = renderer.sharedMaterial;
                        if (material != null)
                        {
                            var shader  = material.shader;
                            var options = new List <string>();
                            for (var i = 0; i < ShaderUtil.GetPropertyCount(shader); i++)
                            {
                                if (ShaderUtil.IsShaderPropertyHidden(shader, i))
                                {
                                    continue;
                                }

                                if (att.propertyType != null)
                                {
                                    var type = ShaderUtil.GetPropertyType(shader, i);
                                    if (att.propertyType == typeof(Color) && type != ShaderUtil.ShaderPropertyType.Color)
                                    {
                                        continue;
                                    }
                                    if (att.propertyType == typeof(Texture) && type != ShaderUtil.ShaderPropertyType.TexEnv)
                                    {
                                        continue;
                                    }
                                    if (att.propertyType == typeof(float) && type != ShaderUtil.ShaderPropertyType.Float && type != ShaderUtil.ShaderPropertyType.Range)
                                    {
                                        continue;
                                    }
                                    if ((att.propertyType == typeof(Vector2) || att.propertyType == typeof(Vector4)) && type != ShaderUtil.ShaderPropertyType.Vector)
                                    {
                                        continue;
                                    }
                                }

                                options.Add(ShaderUtil.GetPropertyName(shader, i));
                            }

                            prop.stringValue = EditorTools.CleanPopup <string>(content.text, prop.stringValue, options);
                            return;
                        }
                    }
                }
            }

            prop.stringValue = EditorGUILayout.TextField(content.text, prop.stringValue);
        }