Question

i want to bind gridview with my custom entity whitch i populate from data base
but i get error
Object reference not set to an instance of an object
i know the error is from my gridlink class
when select new and want to set to link property
in this line : link = { linkName = "tyr", linkSrc = "ytr" },
because when i earase it the error stop and gridview bind
thanks

  public class gridcolumns
{

    public decimal cost { get; set; }
    public Int32 count { get; set; }
    public gridlink link { get; set; }

    public gridcolumns()
    {

        // TODO: Complete member initialization
    }
}

public class gridlink
{
    public string linkName { get; set; }
    public string linkSrc { get; set; }

    public gridlink()
    {

    }
}
 protected void Page_Load(object sender, EventArgs e)
{
    Data281DataContextDataContext conx = new Data281DataContextDataContext();
    List<tbl_2_CheckReqNo_NotValid> allresult = conx.tbl_2_CheckReqNo_NotValids.ToList();
    gridcolumns lastMantWithDate = new gridcolumns();
    if (Request.QueryString.Count == 0)
    {
        var lastMantWithDaste = from pe in allresult //where allresult != null
                                orderby Convert.ToDecimal(pe.mandeh) descending
                                group pe by pe.mant into grouped
                                where grouped != null
                                select new gridcolumns
                                {
                                    link = { linkName = "tyr", linkSrc = "ytr" },
                                    cost = grouped.Sum(g => Convert.ToDecimal(g.mandeh)),
                                    count = grouped.Count(),

                                };

        GrdOstan.DataSource = lastMantWithDaste;
        GrdOstan.DataBind();
    }

Answer 1

You should be instantiating a gridlink like this:

link = new gridlink { linkName = "tyr", linkSrc = "ytr" },

Consider that for each item your query produces you create a gridcolumns object. The link property of that object is initially null; you should set it to new gridlink before trying to use it at all.