title: Activate Visual Web Part Package in Share Point 2010
body: <p>I have created a new project of SharePoint 2010 --> Visual Web part,
  seleted it as form solution. and it created the web part.</p>
  
  <p>I just edited it with Hello World! for confirmation and deployed it using VS, and successfully added to page.</p>
  
  <p>problem, arrises when i activated the same package after uploaded it from site actions--> site settings --> galleries --> Solutions 
  -- > upload new solution --> activate it.</p>
  
  <p><strong>error came:</strong></p>
  
  <p>This solution contains invalid markup or elements that cannot be deployed as part of a sandboxed solution. Solution manifest for solution 'GUID' failed validation, file manifest.xml, line 14, character 4: The element 'Solution' in namespace 'http://schemas.microsoft.com/sharepoint/' has invalid child element 'TemplateFiles' in namespace 'http://schemas.microsoft.com/sharepoint/'. List of possible elements expected: 'FeatureManifests, ActivationDependencies' in namespace 'http://schemas.microsoft.com/sharepoint/'</p>
  
  <p>I don't know why VS didn't get this error while its deployment or i am missing some thing while my deployment.</p>
  
  <p>any idea?</p>