I have change it in this way and now it is running:
<itemtemplate>
<asp:image imageurl="<%# String.IsNullOrEmpty(Eval("CanInsert").ToString()) ? "-" : GetCheckMark(Eval("CanInsert").ToString())%>" id="ImgCanInsert" runat="server" xmlns:asp="#unknown" />
</itemtemplate>
also code behind:
protected string GetCheckMark(string checkd)
{
return checkd == "True" ? "../../../../../ServerFile/Icons/Editor/True.png" : "../../../../../ServerFile/Icons/Editor/False.png";
}
Thanks all