In order to hide all the grid lines, you can configure RadGridView with GridLinesVisibility="None".
If you wish to modify the vertical grid lines around just one column in your grid, you should re-define the template of GridViewCell
so that no vertical lines to be displayed. Using Implicit Styles
gives you the ability to easily extract and edit the default ControlTemplates of the controls. You can follow this article
on two different approaches on how to extract the ControlTemplates.
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