In Fact, you don't need this. You just do like this
<a href='<%#getHREF(Container.DataItem,"Id")%>'>
<img src='<%#getSRC(Container.DataItem,"ImageName") %>' align="middle" border="0" width="80px">
</a>
And ur code behind function will look like this
public string getHREF(object id)
{
return ResolveUrl("~/UserDetails.aspx?Id=" + Id.toString());
}
public string getSRC(object img)
{
if (ImageName == "NoImage")
{
return ResolveUrl(@"~/UserImage/missing.jpg");
}
else
{
return ResolveUrl("~/UserImage/" + img.ToString());
}
}