MVC5 Mqsql Issue - mysql

Question

After Update of Model from database in Entity Framework. Json Data not populate into textbox. when i use DeveloperTool i found a error "There is already an open DataReader associated with this Connection which must be closed first."[Error 505] Help me for resolve this problem.am using MySql in my project. When i use only one table in Model then i didn't get any error but when i update model then my project not working. If i add all the tables in Model then I face same problem.
Here is my code
Controller:-
// GET: Chains
public ActionResult Index()
{
ViewData["chain_name"] = new SelectList(db.chains, "code", "name");
return View(db.chains.ToList());
}
//Action Function callby javascript
[HttpPost]
public ActionResult Action(string code)
{
var query = from c in db.chains
where c.code == code
select c;
return Json(query);//Return Json Result
}
View:-
#using (#Html.BeginForm())
{
#Html.AntiForgeryToken()
<div class="form-horizontal">
<hr />
<div class="form-group">
<label class="col-sm-2 control-label">
Select Chain
</label>
<div class="col-md-3">
#Html.DropDownList("ddlchainname", (SelectList)ViewData["chain_name"], new { onchange = "Action(this.value);", #class = "form-control" })
</div>
</div>
<div class="form-group">
<label class="col-sm-2 control-label">
Chain Name
</label>
<div class="col-md-3">
#Html.TextBox("ChainName", null, new { #class = "form-control" })
</div>
<label class="col-sm-2 control-label">
Username
</label>
<div class="col-md-3">
#Html.TextBox("username", null, new { #class = "form-control" })
</div>
</div>
<div class="form-group">
<label class="col-sm-2 control-label">
Chain Code
</label>
<div class="col-md-3">
#Html.TextBox("ChainCode", null, new { #class = "form-control" })
</div>
</div>
</div>
}
<script type="text/javascript">
function Action(code) {
$.ajax({
url: '#Url.Action("Action", "Chains")',
type: "POST",
data: { "code": code },
"success": function (data) {
if (data != null) {
var vdata = data;
$("#ChainName").val(vdata[0].name);
$("#ChainCode").val(vdata[0].code);
$("#username").val(vdata[0].username);
}
}
});
}

Answer 1

Try this approach:
using (var db = new ChainEntities())
{
ViewData["chain_name"] = new SelectList(db.chains, "code", "name");
return View(db.chains.ToList());
}
This way you open the connection only once then dispose when done.
Sane for action:
[HttpPost]
public ActionResult Action(string code)
{
using (var db = new ChainEntities())
{
var query = from c in db.chains
where c.code == code
select c;
return Json(query);//Return Json Result
}
}