Asp.Net Mvc delete columns from database table

Question

I am trying to delete all table data where username = current user name. But there is some error on lambda expression and conversion."Cannot convert source type to target type. Any help?

public JsonResult DeleteChatMessages(int id)
        {
            string toId = Session["SessionUserName"].ToString();
            tblChat tblchats = _obj.tblChat.Where(p => p.ToId == toId);
            _obj.tblChat.Remove(tblchats);
            _obj.SaveChanges();
            return this.Json(true, JsonRequestBehavior.AllowGet);
        }

Change your line as tblChat tblchats = _obj.tblChat.FirstOrDefault(p => p.ToId == toId) — Mahesh
– Mahesh, Commented Feb 3, 2015 at 7:28

Mahesh · Accepted Answer · 2015-02-03 07:56:01Z

3

I am assuming you are expecting only one object to return from the Where filter. Change your line as,because as per this . The Where clause returns an IEnumerable<TSource>. And you are assigning that to the non IEnumerable object.

  tblChat tblchats = _obj.tblChat.FirstOrDefault(p => p.ToId == toId)

and you also might want to check for the Null, before removing it from the tblChat.

If you are expecting more than one object to match the filter and want to remove all of them then use @tmg approach.

    _obj.tblChat.RemoveRange(_obj.tblChat.Where(p => p.ToId == toId).ToList());

edited Feb 3, 2015 at 7:56

answered Feb 3, 2015 at 7:28

Mahesh

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tmg · Accepted Answer · 2015-02-03 07:35:42Z

2

Filter the "chats" you want.

 var tblchats = _obj.tblChat.Where(p => p.ToId == toId).ToList();

After iterate throught them and remove.

    foeach(chat in tblchats){
        _obj.tblChat.Remove(chat);
    }
    _obj.SaveChanges();

answered Feb 3, 2015 at 7:35

tmg

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