diff --git a/lib/sp-visualizer-list.c b/lib/sp-visualizer-list.c
index 0ea799fa..bb64fa13 100644
--- a/lib/sp-visualizer-list.c
+++ b/lib/sp-visualizer-list.c
@@ -79,7 +79,7 @@ sp_visualizer_list_get_property (GObject    *object,
                                  GValue     *value,
                                  GParamSpec *pspec)
 {
-  SpVisualizerList *self = (SpVisualizerList *)object;
+  SpVisualizerList *self = SP_VISUALIZER_LIST (object);
 
   switch (prop_id)
     {
@@ -102,7 +102,7 @@ sp_visualizer_list_set_property (GObject      *object,
                                  const GValue *value,
                                  GParamSpec   *pspec)
 {
-  SpVisualizerList *self = (SpVisualizerList *)object;
+  SpVisualizerList *self = SP_VISUALIZER_LIST (object);
 
   switch (prop_id)
     {
diff --git a/lib/sp-visualizer-view.c b/lib/sp-visualizer-view.c
index 4175fe6a..d1e2cfeb 100644
--- a/lib/sp-visualizer-view.c
+++ b/lib/sp-visualizer-view.c
@@ -431,7 +431,7 @@ sp_visualizer_view_get_property (GObject    *object,
                                  GValue     *value,
                                  GParamSpec *pspec)
 {
-  SpVisualizerView *self = (SpVisualizerView *)object;
+  SpVisualizerView *self = SP_VISUALIZER_VIEW (object);
 
   switch (prop_id)
     {
@@ -454,7 +454,7 @@ sp_visualizer_view_set_property (GObject      *object,
                                  const GValue *value,
                                  GParamSpec   *pspec)
 {
-  SpVisualizerView *self = (SpVisualizerView *)object;
+  SpVisualizerView *self = SP_VISUALIZER_VIEW (object);
 
   switch (prop_id)
     {