Not sure why I'm getting this C# error

Question

The error is: Using the generic type 'System.Collections.Generic.List<T>' requires 1 type arguments

I have no idea why this is happening, please bare in mind that I'm very new to C# and don't exactly understand how to work with it yet. I'm trying to get the file to retrieve a column from a database table and insert it into a CSV file with extra headers. The database table is cmsDictionary and the column is key, this should populate the CSV key column and the others should be blank to be populated by the user which will then be imported into the cmsLanguageText table.

//This is my controller file which is throwing the error.

using UmbracoImportExportPlugin.Models;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Web;
using System.Web.Mvc;
using System.Text;
using Umbraco.Core.Persistence;
using Umbraco.Web;
using Umbraco.Web.WebApi;
using System.Data;
using System.Data.SqlClient;

namespace UmbracoImportExportPlugin.App_Code
{
    public class ExportDictionaryAllController : UmbracoAuthorizedApiController
    {

        [System.Web.Http.AcceptVerbs("GET", "POST")]
        public static void ExportAll(List<Item> DictionaryItems)
        {
            getList(List<Item> DictionaryItems);
            string attachment = "attachment; filename= DictionaryItems.csv";
            HttpContext.Current.Response.Clear();
            HttpContext.Current.Response.ClearHeaders();
            HttpContext.Current.Response.ClearContent();
            HttpContext.Current.Response.AddHeader("Content-Disposition", attachment);
            HttpContext.Current.Response.ContentType = "text/csv";
            HttpContext.Current.Response.AddHeader("Pragma", "public");
            WriteColumnName();
            foreach (Item item in DictionaryItems)
            {
                WriteItemInfo(item);
            }
            HttpContext.Current.Response.End();
        }

        private static void WriteItemInfo(Item item)
        {
            StringBuilder sb = new StringBuilder();
            AddComma(item.Key, sb);
            AddComma(item.English, sb);
            AddComma(item.Hebrew, sb);
            AddComma(item.Russian, sb);
            HttpContext.Current.Response.Write(sb.ToString());
            HttpContext.Current.Response.Write(Environment.NewLine);
        }

        private static void AddComma(string value, StringBuilder sb)
        {
            sb.Append(value.Replace(',', ' '));
            sb.Append(", ");
        }

        private static void WriteColumnName()
        {
            string columnNames = "Key, English, Hebrew, Russian";
            HttpContext.Current.Response.Write(columnNames);
            HttpContext.Current.Response.Write(Environment.NewLine);
        }

        public List<String> getList(List<Item> DictionaryItems)
        {
            UmbracoDatabase db = ApplicationContext.DatabaseContext.Database;
            var select = new Sql("SELECT key FROM cmsDictionary");
            List<Item> DictionaryItems = db.Fetch<Item>(select);
            return DictionaryItems;
        }
    }
}

@janhartmann I doubt it! See `getList(List DictionaryItems);` for example! — RB., Apr 20 '16 at 08:53
It doesn't compile, it's a compilation error. however when I change `getList(List DictionaryItems);` to `getList(DictionaryItems);` I receive the following error: **An object reference is required for the non-static field, method, or property 'UmbracoImportExportPlugin.App_Code.ExportDictionaryAllController.getList(System.Collections.Generic.List)** — Jonathan Yaniv Ben Avraham, Apr 20 '16 at 08:56
That's because you are trying to call a non static method inside a static method. Either make a new instance of the class or mark the getList method as static. Also you're not using the return value. — Mo Hasan, Apr 20 '16 at 08:59
I don't understand what people mean by the return value, can somebody tell me what I have to return, and if I have to return it in `getList()` or whether I have to return it in `ExportAll()`? — Jonathan Yaniv Ben Avraham, Apr 20 '16 at 09:03
1 do not use [System.Web.Http.AcceptVerbs("GET", "POST")] GET and POST on same method, better to make different http methods for different verbs. 2 getList(List DictionaryItems) method is not static so u cant call it from static method here 3- getList(List DictionaryItems); should be called like getList(DictionaryItems); — Rajdeep, Apr 20 '16 at 09:03

score 2 · Accepted Answer · answered Apr 20 '16 at 08:53

2

Well, this line seems wrong:

getList(List<Item> DictionaryItems);

Should be:

getList(DictionaryItems);

The compiler error should give you a line in the code file where the error is.

answered Apr 20 '16 at 08:53

Paddy

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2

also, return value is not used. – Anton Sizikov Apr 20 '16 at 08:54
What do you mean by return value is not used? I have `return DictionaryItems;` – Jonathan Yaniv Ben Avraham Apr 20 '16 at 08:58
1

He means in the code that calls this method, you don´t use the return-value (consider not the param is changed as it is called by value, not by reference) – MakePeaceGreatAgain Apr 20 '16 at 08:59
2

And getList is not a static method, so it still won't complie.. =/ – Jonas W Apr 20 '16 at 09:00
so I've made `getList(List DictionaryItems)` static. but now I receive this error: **CS0120: An object reference is required for the non-static field, method, or property 'Umbraco.Web.WebApi.UmbracoApiControllerBase.ApplicationContext.get'** – Jonathan Yaniv Ben Avraham Apr 20 '16 at 09:02
Why are these methods all static - there seems to be no need. – Paddy Apr 20 '16 at 09:22
@Paddy I removed static from all of them now and changed the way I called DictionaryItems in the ExportAll method and now it seems not to be giving me any errors. – Jonathan Yaniv Ben Avraham Apr 20 '16 at 09:48

score -1 · Answer 2 · edited Apr 20 '16 at 18:24

-1

Use this as your method definition:

public static List<String> getList(List<Item> DictionaryItems) 
{ 
  UmbracoDatabase db = ApplicationContext.DatabaseContext.Database; 
  var select = new Sql("SELECT key FROM cmsDictionary"); 
  List<string> DictionaryItems = db.Fetch<Item>(select); 
  return DictionaryItems; 
}

edited Apr 20 '16 at 18:24

zx485

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answered Apr 20 '16 at 10:55

Christian Delos Reyes

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3

Not sure why I'm getting this C# error

2 Answers2