Question

I have the following method which is supposed to return a JSONResult so I can use it in an AJAX method with javascript and load autocomplete suggestions for a textbox. I will load this everytime a particular dropdown list changes.

[AcceptVerbs(HttpVerbs.Post), Authorize]
    private JsonResult GetSchemaNodeValues(string SchemaNodeId)
    {
        var query = @"Select ld.""Value"" 
        From ""LookupData"" ld, ""SchemaNode"" sn
        Where sn.""LookupTypeId"" = ld.""LookupTypeId""
        And sn.""SchemaNodeId"" = '{0}'";

        DataSet data = new DataSet();


            data = ServiceManager.GenericService.ExecuteQuery(String.Format(query, SchemaNodeId)).Data;

        var res = data.Tables[0].AsEnumerable().Select(dr => new
        {
            Value = dr["Value"].ToString()
        });

        return JsonConvert.SerializeObject(res);

    }

I get the following error under return JsonConvert.SerializeObject(res);

Error   106 Cannot implicitly convert type 'string' to 'System.Web.Mvc.JsonResult'  

Is there any way to get past this?

Before this I tried using System.Web.mvc.Controller.Json(res); which returns a JSONResult from an object.

But I couldn’t use it because my class is a PageDialog not a Controller so it doesn’t have access to Controller’s protected internal methods like JSon(). The error I got was that JSon() is inaccessible due to its protection level. The Controller class was locked and I can’t make it public or create a workaround so I changed the approach using JsonConvert.SerializeObject(res);

Any suggestions would be extremely welcome.

Answer 1

private dynamic GetSchemaNodeValues(string SchemaNodeId)
{
    ...
    return data.Tables[0].AsEnumerable().Select(dr => new
    {
        Value = dr["Value"].ToString()
    });
}

or

private string GetSchemaNodeValues(string SchemaNodeId)
{
    ...
    var result = data.Tables[0].AsEnumerable().Select(dr => new
    {
        Value = dr["Value"].ToString()
    });
    return JsonConvert.SerializeObject(result);
}