Image Gallery Webpart issue

Hello,

In my Kentico 9 application, I am using Image Gallery webpart as control under a repeater webpart transformation and need to set Media Gallery webpart's "MediaLibraryPath" property dynamically.

Here is my repeater transformation code:

<%@ Register Src="~/CMSModules/MediaLibrary/Controls/LiveControls/MediaGallery.ascx" TagName="MediaGallery" TagPrefix="cms" %>

<cms:MediaGallery ID="gallery"  HideFolderTree="true" FileIDQueryStringKey="fileid" runat="server"  MediaLibraryName="ImageSets" TransformationName="Transformations.MediaLibrary_Showcase_Images"/>


<script runat="server">
  protected override void OnInit(EventArgs e) 
  {
      gallery.MediaLibraryPath = "_Showcase"; 
      gallery.ReloadData(true);
  }
</script>

But seems "MediaLibraryPath" properties not populating properly with above, instead of if trying like follows:

<cms:MediaGallery ID="gallery" MediaLibraryPath = "_Showcase" HideFolderTree="true" FileIDQueryStringKey="fileid" runat="server" MediaLibraryName="ImageSets" TransformationName="Transformations.MediaLibrary_Showcase_Images"/>

Getting expected result, but as per requirement need to set "MediaLibraryPath" dynamically from server script.

Please suggest what I am missing?

Thanks in advance.