Successfully upgraded from DNN 7.4.2 to DNN 8.0.2.  After upgrading the site is giving build failed error. The following are the errors:

Error 3 Could not load type 'DotNetNuke.UI.WebControls.SolPartActions'. Blog\admin\Containers\solpartactions.ascx

To resolve the issue I have removed the  If I remove the file solpartactions.ascx it is giving some other errors like dnn:combobox is not identified.

Please advise if there is any quick solution. 

Please explain the solution in detail (step by step).

Hi , I am not getting the error in the Register tag at the top of the page as you mentioned .

But the problem is after upgrading the dnn platform, while compiling the website I am facing the errors like :

1. File : admin\containers\actions.ascx

Error : Could not load type 'DotNetNuke.UI.WebControls.SolPartActions'. 

At line : <%@ Control Language="C#" AutoEventWireup="false" Inherits="DotNetNuke.UI.WebControls.SolPartActions"%> 

2. File : DesktopModules\Admin\Vendors\Banners.ascx.cs

Error : The type or namespace name 'Vendors' does not exist in the namespace 'DotNetNuke.Services' (are you missing an assembly reference?) 

At Line : using DotNetNuke.Services.Vendors;

Because of this Vendors namespace not found it is not able to get the reference for the BannerController and BannerType and throwing the following errors

Error 13 The type or namespace name 'BannerController' could not be found (are you missing a using directive or an assembly reference?) 

Error 14 The name 'BannerType' does not exist in the current context 

Query : What is the first step to get over with these errors . Please advise.