EditorGUI.ObjectField without object picker

ObjectFieldEx.cs

internal static class ObjectFieldEx
{
    private static readonly int s_ObjectFieldHash = "s_ObjectFieldHash".GetHashCode();
    internal const float kSingleLineHeight = 18f;
    private const float kIndentPerLevel = 15;

    public static Object ObjectField(Object obj, Type objType, params GUILayoutOption[] options)
    {
        Rect r = EditorGUILayout.GetControlRect(true, kSingleLineHeight, options);
        return ObjectField(r, obj, objType);
    }

    public static Object ObjectField(Rect position, Object obj, Type objType)
    {
        int id = GUIUtility.GetControlID(s_ObjectFieldHash, FocusType.Keyboard, position);
        return DoObjectField(IndentedRect(position), IndentedRect(position), id, obj, objType);
    }

    internal static Object DoObjectField(Rect position, Rect dropRect, int id, Object obj, System.Type objType)
    {
        Event evt = Event.current;
        EventType eventType = evt.type;

        // special case test, so we continue to ping/select objects with the object field disabled
        if (!GUI.enabled && (Event.current.rawType == EventType.MouseDown))
            eventType = Event.current.rawType;

        bool hasThumbnail = EditorGUIUtility.HasObjectThumbnail(objType);


        Vector2 oldIconSize = EditorGUIUtility.GetIconSize();
        EditorGUIUtility.SetIconSize(new Vector2(12, 12));  // Have to be this small to fit inside a single
        switch (eventType)
        {
            case EventType.MouseDown:
                // Ignore right clicks
                if (Event.current.button != 0)
                    break;
                if (position.Contains(Event.current.mousePosition))
                {
                    EditorGUIUtility.editingTextField = false;

                    Object actualTargetObject = obj;
                    Component com = actualTargetObject as Component;
                    if (com)
                        actualTargetObject = com.gameObject;

                    // One click shows where the referenced object is, or pops up a preview
                    if (Event.current.clickCount == 1)
                    {
                        GUIUtility.keyboardControl = id;

                        EditorGUIUtility.PingObject(actualTargetObject);
                        evt.Use();
                    }
                    // Double click opens the asset in external app or changes selection to referenced object
                    else if (Event.current.clickCount == 2)
                    {
                        if (actualTargetObject)
                        {
                            AssetDatabase.OpenAsset(actualTargetObject);
                            GUIUtility.ExitGUI();
                        }
                        evt.Use();
                    }
                }
                break;
            case EventType.Repaint:
                GUIContent temp = EditorGUIUtility.ObjectContent(obj, objType);
                temp.tooltip = obj.name;
                style.Draw(position, temp, id, DragAndDrop.activeControlID == id, position.Contains(Event.current.mousePosition));
                break;
        }

        EditorGUIUtility.SetIconSize(oldIconSize);

        return obj;
    }

    internal static GUIStyle _style;
    internal static GUIStyle style
    {
        get
        {
            if (_style == null)
            {
                _style = new GUIStyle(EditorStyles.textField);
                _style.imagePosition = ImagePosition.ImageLeft;
            }
            return _style;
        }
    }

    internal static float indent => EditorGUI.indentLevel * kIndentPerLevel;

    // Apply the indentLevel to a control rect
    public static Rect IndentedRect(Rect source)
    {
        float x = indent;
        return new Rect(source.x + x, source.y, source.width - x, source.height);
    }
}