NullReferenceException was unhandled

[tookerello]

Hi could you please help with this as i have been trying to correct it for hours:
I keep receiving the "NullReferenceE xception was unhandled" message

public static Conditions GetCurrentConditions(string location)
        {
            Conditions c;
            c = null;
            c = new Conditions();

            c.GetCurrentConditions();

            XmlDocument xmlConditions = new XmlDocument();
            xmlConditions.Load(string.Format("http://www.google.com/ig/api?weather={0}", location));
            if (xmlConditions.SelectSingleNode("xml_api_reply/weather/problem_cause") != null)
            {
                c = null;
            }
            else
            {
                Conditions cond = new Conditions();
                cond.Town = xmlConditions.SelectSingleNode("/xml_api_reply/weather/forecast_information/city").Attributes["data"].InnerText;
                cond.Condition = xmlConditions.SelectSingleNode("/xml_api_reply/weather/current_conditions/condition").Attributes["data"].InnerText;
                cond.TempC = xmlConditions.SelectSingleNode("/xml_api_reply/weather/current_conditions/temp_c").Attributes["data"].InnerText;
                cond.TempF = xmlConditions.SelectSingleNode("/xml_api_reply/weather/current_conditions/temp_f").Attributes["data"].InnerText;
                cond.Humidity = xmlConditions.SelectSingleNode("/xml_api_reply/weather/current_conditions/humidity").Attributes["data"].InnerText;
                cond.Wind = xmlConditions.SelectSingleNode("/xml_api_reply/weather/current_conditions/wind_condition").Attributes["data"].InnerText;

            }

            return c;
        }

[Monomachus]

Hi could you please help with this as i have been trying to correct it for hours:
I keep receiving the "NullReferenceE xception was unhandled" message

public static Conditions GetCurrentCondi tions(string location)
{
Conditions c;
c = null;
c = new Conditions();

c.GetCurrentCon ditions();

XmlDocument xmlConditions = new XmlDocument();
xmlConditions.L oad(string.Form at("http://www.google.com/ig/api?weather={0} ", location));
if (xmlConditions. SelectSingleNod e("xml_api_repl y/weather/problem_cause") != null)
{
c = null;
}
else
{
Conditions cond = new Conditions();
cond.Town = xmlConditions.S electSingleNode ("/xml_api_reply/weather/forecast_inform ation/city").Attribut es["data"].InnerText;
cond.Condition = xmlConditions.S electSingleNode ("/xml_api_reply/weather/current_conditi ons/condition").Att ributes["data"].InnerText;
cond.TempC = xmlConditions.S electSingleNode ("/xml_api_reply/weather/current_conditi ons/temp_c").Attrib utes["data"].InnerText;
cond.TempF = xmlConditions.S electSingleNode ("/xml_api_reply/weather/current_conditi ons/temp_f").Attrib utes["data"].InnerText;
cond.Humidity = xmlConditions.S electSingleNode ("/xml_api_reply/weather/current_conditi ons/humidity").Attr ibutes["data"].InnerText;
cond.Wind = xmlConditions.S electSingleNode ("/xml_api_reply/weather/current_conditi ons/wind_condition" ).Attributes["data"].InnerText;

}

return c;
}

put a try-catch block into your method GetCurrentCondi tions and see where exactly it throws exception and tell us more details.

[tlhintoq]

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[tlhintoq]

Original Poster: "How do I fix a 'object reference not set to an instance of an object' error?

The line your code stopped on while debugging holds all your answers.
One of the variables/objects was created but not initialized. For example:

string TempString;// Created but not initialized so this is still null
//versus
string TempString = string.empty;

Debug your project again. This time, when it breaks on a line look at the Locals pallet to see which variable/object is null. You can also hover your mouse over each variable and the hothelp will shows its value. One of them will be null.

[tlhintoq]

Conditions c;
            c = null;
            c = new Conditions();

can be reduced to

Conditions c = new Conditions();

Why have 3 lines when 1 will do just as cleanly?