In design page :
<ItemTemplate>
<asp:LinkButton ID="LinkButton_File" runat="server" CommandName='<%# DataBinder.Eval(Container, "DataItem.FileName") %>'
CommandArgument='<%#Eval("FilePath") %>' Text='<%# Eval("FileName") %>'>
</asp:LinkButton>
</ItemTemplate>
And in code behind
protected void EventFileDetailsItemCommand(object source, GridCommandEventArgs e)
{
if (e.CommandName == "DeleteFile")
{
string[] commandArgs = e.CommandArgument.ToString().Split(new char[] { ',' });
var filePath = commandArgs[1].ToString();