I want to add styles to the web part pages in visual studio. Is it possible to use CssLink? How This control works?
You can use
CssRegistration or simple
link html tag for your custom styles control in
<SharePoint:CssRegistration Name="/_layouts/15/MySolutionFolder/CSS/styles.css?v1" runat="server" />
CssLink control does big job with SP default styles, read more here.
The difference between CssLink and CssRegistration :
If you want to add styles to the web part pages , I suggest you can use CssRegistration because CssLink server control must reside on the master page .