include multiple attachments with different types in the same transformation

I guess this page might give you an idea how to implement this: https://docs.kentico.com/k10/managing-website-content/configuring-the-environment-for-content-editors/creating-grouped-page-attachments.

So to display attachments from another field you can add another control <cms:DocumentAttachments ID="ucDocImagesField" runat="server" /></a> and make appropriate assignment of AttachmentGroupGUID, Transformation etc., as in code above.

I already tried that but faced a lot of errors, can you please show me what would be the form of Init function if i want to implement 2 controls?

I suppose that there should be something like this:

  CMS.FormEngine.FormFieldInfo ffi2 = fi.GetFormField("AnotherImagesField");  
  Guid AttachmentGroupGUID2 = ffi2.Guid;
  ucDocImagesField.Path = Eval<string> ("NodeAliasPath");
  ucDocImagesField.AttachmentGroupGUID = AttachmentGroupGUID2;
  ucDocImagesField.TransformationName = "CMS.Root.Attachment";
  ucDocImagesField.ReloadData(true);

  and in ascx file add another control
  <cms:DocumentAttachments ID="ucDocImagesField" runat="server" />

Previously I tried this code:

 protected override void OnInit(EventArgs e)

{

CMS.DataEngine.DataClassInfo dci = CMS.DataEngine.DataClassInfoProvider.GetDataClassInfo(Eval("ClassName").ToString(), true);
if (dci != null)
{
  CMS.FormEngine.FormInfo fi = new CMS.FormEngine.FormInfo(dci.ClassFormDefinition);
  // field name we added in the page type
  CMS.FormEngine.FormFieldInfo ffi = fi.GetFormField("Images");  
       CMS.FormEngine.FormFieldInfo ffi1= fi.GetFormField("Reports");
  Guid AttachmentGroupGUID = ffi.Guid;
        Guid AttachmentGroupGUID1= ffi1.Guid;
  ucDocAttachments.Path = Eval<string>("NodeAliasPath");
        ucDocFileAttachs.Path = Eval<string>("NodeAliasPath");
  ucDocAttachments.AttachmentGroupGUID = AttachmentGroupGUID;
        ucDocFileAttachs.AttachmentGroupGUID = AttachmentGroupGUID1;
  ucDocAttachments.TransformationName = "CMS.Root.Attachment";
        ucDocFileAttachs.TransformationName = "CMS.Root.AttachmentList";
  ucDocAttachments.ReloadData(true);
        ucDocFileAttachs.ReloadData(true);
}

}

where in AttachmentList transformation I have this:

< div> <a target="_blank" href="<%# GetAbsoluteUrl(GetAttachmentUrl(Eval("AttachmentName"), Eval("NodeAliasPath")), Eval < int>("AttachmentSiteID")) %>" download > <%# Eval("AttachmentName",true) %> < /a> < /div>

but it returns this error: [Error loading the control 'Repeater', check event log for more details]

Could you please check event log and send me the error you are getting?

Event ID: 4489

Event type: Error

Event time: 11/28/2017 12:50:17 PM

Source: Control

Event code: LOAD

User ID: 65

User name: public

Description: Message: Object reference not set to an instance of an object.

Exception type: System.NullReferenceException

Stack trace:

at ASP.cmsvirtualfiles_transformations__vg_81685704_be55_473f_8a2f_a53f2e59180d_custom_elections_selectedelection_ascx.OnInit(EventArgs e) in http://server/Lade/CMSVirtualFiles/Transformations/=vg=81685704-be55-473f-8a2f-a53f2e59180d/custom.Elections/selectedElection.ascx:line 15 at System.Web.UI.Control.InitRecursive(Control namingContainer) at System.Web.UI.Control.InitRecursive(Control namingContainer) at System.Web.UI.Control.AddedControl(Control control, Int32 index) at System.Web.UI.ControlCollection.Add(Control child) at System.Web.UI.WebControls.Repeater.CreateItem(Int32 itemIndex, ListItemType itemType, Boolean dataBind, Object dataItem) at System.Web.UI.WebControls.Repeater.CreateControlHierarchy(Boolean useDataSource) at CMS.DocumentEngine.Web.UI.BasicRepeater.CreateControlHierarchy(Boolean useDataSource) at System.Web.UI.WebControls.Repeater.OnDataBinding(EventArgs e) at System.Web.UI.WebControls.Repeater.DataBind() at CMS.DocumentEngine.Web.UI.BasicRepeater.DataBind() at CMS.DocumentEngine.Web.UI.CMSRepeater.DataBind() at CMS.DocumentEngine.Web.UI.CMSRepeater.ReloadDataInternal(Boolean forceReload) at CMS.DocumentEngine.Web.UI.CMSRepeater.<>c__DisplayClass3.b__2() at CMS.Base.Web.UI.ControlsExtensions.CallHandled(Control ctrl, Action func)

Does you .ascx file contain repeater, and repeater transformation contains control <cms:DocumentAttachments ID="ucDocImagesField" runat="server" />?

If yes, you should use ItemDataBound event of repeater and there you should initialize attachments control.

the .ascx contains a basic repeater and the transformation is already shared as it is, can you please explain more what should be included in the ItemDataBound event? or how to initialize the attachments control? also one more question, the Images attachment worked really well, why am I facing this problem with the second attachment field if I am applying almost the same code for both.

It is quite difficult to judge about the issue not seeing it, but what I can see as a problem, that if your repeater has attachment control in transformation, it might be incorrectly init it in OnInit event. Is it your OnInit Script is in transformation? Do you use some custom web part with ascx and code behind? Do you display your attachments on Election details page? Can you send screenshot of you transformation? As by event log details the issue is in line 15 of your transformation.

You put the CMS.Root.AttachmentLinks** transformation for second control. Please make sure that such transformation exists. Maybe there should be CMS.Root.AttachmentList

And also check attachment fields names. I tried to use you transformation and it works well with correct transfromation names and Repeater webpart.

yes the transformation exists, I created it, but also when I use CMS.Root.Attachment I face the same error, also I double checked the names, and everything looks fine, one more question please, is it okay to use the same control "DocumentAttachments" for both attachment fields? or should I use separate controls?

well it turned out that the Basic Repeater that I was using was firing all these errors, I replaced it with a repeater and it worked fine, thank you for your help :)