Using a Repeater DataBinder to link JSON to C# class - error

Question

I am trying to bind my class using a Repeater Databind. However I get an error and not sure what I am doing wrong.

I should point out that the binding works when I use weatherinfo.list, but if I just use weatherinfo I get an error message:

An exception of type 'System.ArgumentException' occurred in System.Web.dll but was not handled in user code

Additional information: An invalid data source is being used for Repeater_weatherReports. A valid data source must implement either IListSource or IEnumerable.

My C# code is:

public partial class _Default : System.Web.UI.Page
{
    string city_name;
    string temp_min;
    string temp_max;
    string humidity;
    string weatherdate;

    protected void Page_Load(object sender, EventArgs e)
    {
    }

    protected void reptrData_ItemCommand(object source, RepeaterCommandEventArgs e)
    {
        Label lblCity = e.Item.FindControl("lblCity_Country") as Label;
        city_name = lblCity.Text;

        Label lblHumidity = e.Item.FindControl("Label_humidity") as Label;
        humidity = lblHumidity.Text;

        Label LblMin = e.Item.FindControl("Label_min") as Label;
        humidity = lblHumidity.Text;

        Label LblMax = e.Item.FindControl("Label_max") as Label;
        temp_max = lblHumidity.Text;

        Label LblDate = e.Item.FindControl("DateWeather") as Label;
        weatherdate = LblDate.Text;
    }

    protected void GetWeatherInfo(object sender, EventArgs e)
    {
        string appID = "hidden";
        //string url = string.Format("http://api.openweathermap.org/data/2.5/weather?q={0}&units=metric&cnt=2&APPID={1}",txtCity.Text,appID);

        string url = string.Format("http://api.openweathermap.org/data/2.5/forecast?q={0},us&units=metric&cnt=5&APPID={1}", txtCity.Text, appID);

        using (WebClient client = new WebClient())
        {
            string json = client.DownloadString(url);

            JavaScriptSerializer serializer = new JavaScriptSerializer();

            WeatherInfo weatherinfo = serializer.Deserialize<WeatherInfo>(json);

            Repeater_weatherReports.DataSource = weatherinfo;//weatherinfo.list;
            Repeater_weatherReports.DataBind();

            foreach (List list in weatherinfo.list)
            {
                // if (list.main != null && list.main.city != null && list.main.city.name != null)
                if (list.main != null && weatherinfo.city != null)

                {
                    city_name = weatherinfo.city.name;  //list.main.city.name;
                    weatherdate = list.main.weatherdate;
                    //lblDescription.Text = weatherinfo.list[0].weather[0].description;

                    temp_min = string.Format("{0}", Math.Round(list.main.temp_min, 1));
                    temp_max = string.Format("{0}", Math.Round(list.main.temp_max, 1));
                    humidity = list.main.humidity.ToString();
                }
                // tblWeather.Visible = true;
            }

            //lblCity_Country.Text = weatherinfo.city.name;
            ////lblDescription.Text = weatherinfo.list[0].weather[0].description;

            //lblTempMin.Text = string.Format("{0}", Math.Round(weatherinfo.list[0].main.temp_min, 1));
            //lblTempMax.Text = string.Format("{0}", Math.Round(weatherinfo.list[0].main.temp_max, 1));

            //lblHumidity.Text = weatherinfo.list[0].main.humidity.ToString();
            //tblWeather.Visible = true;

            //SqlConnection con = new SqlConnection(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Users\vagheld\Documents\Visual Studio 2015\WebSites\WeatherAPI\App_Data\Weatherdatabase.mdf;Integrated Security=True");

            //con.Open();
            //SqlCommand cmd = con.CreateCommand();
            //cmd.CommandType = System.Data.CommandType.Text;
            //cmd.CommandText = "INSERT INTO weather values ('"+lblCity_Country.Text+"', '"+lblTempMin.Text + "', '"+lblTempMax.Text + "', '"+DateTime.Now+"'     )";
            //cmd.ExecuteNonQuery();
            //con.Close();

            /*
            lblCity_Country.Text = weatherinfo.city.name + "," + weatherinfo.city.country;
            lblDescription.Text = weatherinfo.list[0].weather[0].description;

            lblTempMin.Text = string.Format("{0}.c", Math.Round(weatherinfo.list[0].temp.min, 1));
            lblTempMax.Text = string.Format("{0}.c", Math.Round(weatherinfo.list[0].temp.max, 1));

            lblHumidity.Text = weatherinfo.list[0].humidity.ToString();
            tblWeather.Visible = true;
            */
        }
    }

    public class WeatherInfo
    {
        public string cod { get; set; }
        public double message { get; set; }
        public int cnt { get; set; }
        public IList<List> list { get; set; }
        public City city { get; set; }
    }

    public class Main
    {
        public double temp { get; set; }
        public string weatherdate { get; set; }
        public double temp_min { get; set; }
        public double temp_max { get; set; }
        public double pressure { get; set; }
        public double sea_level { get; set; }
        public double grnd_level { get; set; }
        public int humidity { get; set; }
        public double temp_kf { get; set; }
        // public City city { get; set; }
    }

    public class Weather
    {
        public int id { get; set; }
        public string main { get; set; }
        public string description { get; set; }
        public string icon { get; set; }
    }

    public class Clouds
    {
        public int all { get; set; }
    }

    public class Wind
    {
        public double speed { get; set; }
        public double deg { get; set; }
    }

    public class Sys
    {
        public string pod { get; set; }
    }

    public class List
    {
        public int dt { get; set; }
        public Main main { get; set; }
        public IList<Weather> weather { get; set; }
        public Clouds clouds { get; set; }
        public Wind wind { get; set; }
        public Sys sys { get; set; }
        public string dt_txt { get; set; }
    }

    public class Coord
    {
        public double lat { get; set; }
        public double lon { get; set; }
    }

    public class City
    {
        public int id { get; set; }
        public string name { get; set; }
        public Coord coord { get; set; }
        public string country { get; set; }
    }
}

Part of my aspx code:

<asp:Repeater ID="Repeater_weatherReports" runat="server" onitemcommand="reptrData_ItemCommand">
    <ItemTemplate>
        <table id="tblWeather" border="0" visible="true">
            <tr>
                <th>
                    Weather Info
                </th>
            </tr>
            <tr>
                <td>
                    <asp:Label runat="server" ID="lblCity_Country" Text='<%# Eval("city") %>' />&nbsp;
                    <asp:Label runat="server" ID="DateWeather" Text='<%# Eval("main.weatherdate") %>' />&nbsp;
                    humidity:<asp:Label runat="server" ID="Label_humidity" Text='<%# Eval("main.humidity") %>' />
                </td>
            </tr>
            <tr>    
                <td>
                    min:<asp:Label runat="server" ID="Label_min" Text='<%# Eval("main.temp_min") %>' />
                    max:<asp:Label runat="server" ID="Label_max" Text='<%# Eval("main.temp_max") %>' />
                </td>
            </tr>
        </table>
    </ItemTemplate>
</asp:Repeater>

I can't figure out why the binding works with 'weatherinfo.list' but not 'weatherinfo'. Any ideas?

Answer 1

This because WeatherInfo class is itself not a collection. While WeatherInfo.list is an implementation of IListSource. So while binding a datasource you need a collection object which must implement IListSource or IEnumerable interfaces.