Develop Reference

get a string value from its name

I have a string name given to me in a string.
Like this:
string myawesomestring = "hey";
string mystringname = "myawesomestring";
I need to get myawesomestring value but the myawesomestring can change.
I hope you get what I mean, if you don't comment I will fix it myself.

Something like this?
string mystringname += myawesomestring;

I understand that you want to read the value of a string by some kind of string value stored in another variable (which is dynamic). I don't think this can be achieved with just simple string data type, but you can do this by using some complex data types like dictionary or class or something similar.
First solution might be storing the data in a dictionary, but you have to make sure the keys are unique. E.g.
string mystringname1 = "MyAwesomeString1";
string mystringname2 = "MyAwesomeString2";
var awesomeStrings = new Dictionary<string, string>
{
{"MyAwesomeString1","hey1" },
{"MyAwesomeString2","hey2" }
};
string vaule1 = awesomeStrings[mystringname1];
string vaule2 = awesomeStrings[mystringname2];
If you have more attributes, then you can create a class and with the use of little bit of reflection, you can easily read the property values. E.g.
public class AwesomeString
{
public string MyAwesomeString1 { get; set; } = "hey1";
public string MyAwesomeString2 { get; set; } = "hey2";
}
class Program
{
static void Main(string[] args)
{
string mystringname1 = "MyAwesomeString1";
string mystringname2 = "MyAwesomeString2";
AwesomeString awesomeString = new AwesomeString();
string vaule1 = (string)awesomeString.GetType().GetProperty(mystringname1).GetValue(awesomeString);
string vaule2 = (string)awesomeString.GetType().GetProperty(mystringname2).GetValue(awesomeString);
/* ... */
}
}

C# problem with object array

I am fairly new to arrays in C# and am used to storing a mass of data in a string and in INI files and then breaking it down into basic arrays using delimiters...so yeh, my knowledge is almost none existent.
My main form class begin this definition:
public CAirportData[] _AirportData; //size not known
This is the method I am using to create the array:
...string[] airports = possibleAirports.Split(','); //size is known
foreach (string airport in airports)
{
string[] rwys = inif.Read(airport, "rwys").Split(':'); //size is known (2)
_AirportData = new CAirportData[] { new CAirportData() { icao=airport, depRwy=rwys[0], arrRwy=rwys[1] } };
}
I know this just boils down to my limited knowledge of objects and arrays. But I can't seem to find anything on the internet that uses this sort of thing. I have tried to combine other peoples code with little success.
I need the _AirportData array to be available outside of the form hence public and declared outside of any methods. I supose the main problem is that I am overwriting array and foreach airport I am creating a new array hence loosing the previous. I had tried moving the ..= new CAirportData[] to all sorts of places but Visual Studio doesn't like it.
Below is the class definition for CAirportData:
public class CAirportData
{
public string icao { get; set; }
public string depRwy { get; set; }
public string arrRwy { get; set; }
public override string ToString()
{
string result = string.Format("ICAO: {0}, Dep: {1}, Arr: {2}", this.icao, this.depRwy, this.arrRwy);
return result;
}
}
public class CMRunways
{
public string icao { get; set; }
public string depRwy { get; set; }
public string arrRwy { get; set; }
}
Many thanks in advance for any help!

What you're looking for is generic List. Change the definition to:
public List<CAirportData> _AirportData = new List<CAirportData>();
Then the code in the loop to:
_AirportData.Add(new CAirportData { icao=airport, depRwy=rwys[0], arrRwy=rwys[1] });

This is what I would do...Create a static class, with a static property (airports) and add a static constructor to load the airports from file at the begining.
public static class Session
{
public static CAirportData[] _AirportData;
static Session()
{
string airports = possibleAirports.Split(",");
foreach (string airport in airports)
{
string[] rwys = inif.Read(airport, "rwys").Split(':'); //size is known (2)
_AirportData = new CAirportData[] { new CAirportData() { icao=airport, depRwy=rwys[0], arrRwy=rwys[1] } };
}
}
}
Now you can access the array anywhere in the project like
MessageBox.Show(Session.CAirportData[0].depRwy);

Dictionary of Objects doesn't work as JSON

I have spent WAY too much time trying to figure out how to pull all the values I need to from my C# application using JS and JSON. It works fine when I just use simple structures, such as an array, but I need to be able to grow the list at runtime.
Right now, the best I could figure out was doing a Dictionary with an incrementing key value, and the other 3 values as a class object. However, this seems to crash out my C# application.
What would be the best way to do this?
Relevant C# Code:
public class ChatData
{
string userName;
string message;
System.DateTime timestamp;
public ChatData(string name, string msg)
{
userName = name;
message = msg;
timestamp = System.DateTime.Now;
}
}
else if (string.Equals(request, "getchat"))
{
//string since = Request.Query.since;
Dictionary<int, ChatData> data = new Dictionary<int, ChatData>();
data.Add(1, new ChatData("bob", "hey guys"));
data.Add(2, new ChatData("david", "hey you"));
data.Add(3, new ChatData("jill", "wait what"));
return Response.AsJson(data);
}
Relevant Javascript:
function getChatData()
{
$.getJSON(dataSource + "?req=getchat", "", function (data)
{
//$.each(data, function(key, val)
//{
//addChatEntry(key, val);
//})
});
}

You haven't explained what Response.AsJson is and how it is implemented but if it uses JavaScriptSerializer you will get the following exception:
Unhandled Exception: System.ArgumentException: Type
'System.Collections.Generic. Dictionary`2[[System.Int32, mscorlib,
Version=4.0.0.0, Culture=neutral,
PublicKeyToken=b77a5c561934e089],[ChatData, Test, Version=1.0.0.0,
Culture=neutral, PublicKeyToken=null]]' is not supported for
serialization/deserialization of a dictionary, keys must be strings or
objects.
which is pretty self-explanatory. You cannot use integers as keys if you intend to JSON serialize this structure. Also because your ChatData class no longer has a default/parameterless constructor you won't be able to deserialize a JSON string back to this class (but I guess you don't need this yet).
So one possible solution to your problem would be to use:
Dictionary<string, ChatData> data = new Dictionary<string, ChatData>();
data.Add("1", new ChatData("bob", "hey guys"));
data.Add("2", new ChatData("david", "hey you"));
data.Add("3", new ChatData("jill", "wait what"));
Now of course this being said and looking at the javascript you commented out and what you intend to do, as I already explained you in your previous question, dictionaries are not serialized as javascript arrays, so you cannot loop over them.
Long story short, define a class:
public class ChatData
{
public string Username { get; set; }
public string Message { get; set; }
public DateTime TimeStamp { get; set; }
}
and then fill an array of this class:
var data = new[]
{
new ChatData { Username = "bob", Message = "hey guys" },
new ChatData { Username = "david", Message = "hey you" },
new ChatData { Username = "jill", Message = "wait what" },
};
return Response.AsJson(data);
and finally consume:
$.getJSON(dataSource, { req: 'getchat' }, function (data) {
$.each(data, function(index, element) {
// do something with element.Username and element.Message here, like
$('body').append(
$('<div/>', {
html: 'user: ' + element.Username + ', message:' + element.Message
})
);
});
});

Why not simply use a typed list? Also, you'll need a default constructor to serialize/deserialize it. Note how I've modified your class to use properties
as well. Note, as #rudolf_franek mentions, you can add an ID property to the ChatData class if you need to be able to link to it.
public class ChatData
{
public ChatData()
{
TimeStamp = DateTime.Now;
}
public int ID { get; set; }
public string Who { get; set; }
public string Said { get; set; }
public DateTime TimeStamp { get; set; }
}
...
var data = new List<ChatData>
{
new ChatData { ID = 1, Who = "bob", Said = "hey guys" },
...
};
return Response.AsJson( data );

Using DefaultIfEmpty with an object?

I saw an example on MSDN where it would let you specify the default value if nothing is returned. See below:
List<int> months = new List<int> { };
int firstMonth2 = months.DefaultIfEmpty(1).First();
Is it possible to use this functionality with an object? Example:
class object
{
int id;
string name;
}
code:
List<myObjec> objs = new List<myObjec> {};
string defaultName = objs.DefaultIfEmpty(/*something to define object in here*/).name;
UPDATE:
I was thinking I could do something like this:
List<myObjec> objs = new List<myObjec> {};
string defaultName = objs.DefaultIfEmpty(new myObjec(-1,"test")).name;
But haven't been able to. It should be noted that I am actually trying to use this method on an object defined in my DBML using LINQ-To-SQL. Not sure if that makes a difference in this case or not.

You need to pass an instantiated class as a parameter of the DefaultIfEmpty.
class Program
{
static void Main(string[] args)
{
var lTest = new List<Test>();
var s = lTest.DefaultIfEmpty(new Test() { i = 1, name = "testing" }).First().name;
Console.WriteLine(s);
Console.ReadLine();
}
}
public class Test
{
public int i { get; set; }
public string name { get; set; }
}
To add to it and make it a bit more elegant (IMO) add a default constructor:
class Program
{
static void Main(string[] args)
{
var lTest = new List<Test>();
var s = lTest.DefaultIfEmpty(new Test()).First().name;
Console.WriteLine(s);
Console.ReadLine();
}
}
public class Test
{
public int i { get; set; }
public string name { get; set; }
public Test() { i = 2; name = "testing2"; }
}

As per the MSDN page on this Extension Method you can do what you want:
http://msdn.microsoft.com/en-us/library/bb355419.aspx
Check the sample on this page for an example on how to use this with an object.

i must admit i am not too sure i understand your question, but i'll try to suggest using double question mark if the returned object might be null. Like so:
myList.FirstOrDefault() ?? new myObject();

You can create a default Object Like this:
Object o_Obj_Default = new Object();
o_Obj_Default.id = 3;
o_Obj_Default.name = "C";
And add it to your default value :
string defaultName = objs.DefaultIfEmpty(o_Obj_Default).First().name;
If your list "objs" is empty, the result will be "C"

JSON Twitter List in C#.net

My code is below. I am not able to extract the 'name' and 'query' lists
from the JSON via a DataContracted Class (below)
I have spent a long time trying to work this one out, and could really do
with some help...
My Json string:
{"as_of":1266853488,"trends":{"2010-02-22
15:44:48":[{"name":"#nowplaying","query":"#nowplaying"},{"name":"#musicmonday","query":"#musicmonday"},{"name":"#WeGoTogetherLike","query":"#WeGoTogetherLike"},{"name":"#imcurious","query":"#imcurious"},{"name":"#mm","query":"#mm"},{"name":"#HumanoidCityTour","query":"#HumanoidCityTour"},{"name":"#awesomeindianthings","query":"#awesomeindianthings"},{"name":"#officeformac","query":"#officeformac"},{"name":"Justin
Bieber","query":"\"Justin Bieber\""},{"name":"National
Margarita","query":"\"National Margarita\""}]}}
My code:
WebClient wc = new WebClient();
wc.Credentials = new NetworkCredential(this.Auth.UserName, this.Auth.Password);
string res = wc.DownloadString(new Uri(link));
//the download string gives me the above JSON string - no problems
Trends trends = new Trends();
Trends obj = Deserialise<Trends>(res);
private T Deserialise<T>(string json)
{
T obj = Activator.CreateInstance<T>();
using (MemoryStream ms = new MemoryStream(Encoding.Unicode.GetBytes(json)))
{
DataContractJsonSerializer serialiser = new DataContractJsonSerializer(obj.GetType());
obj = (T)serialiser.ReadObject(ms);
ms.Close();
return obj;
}
}
[DataContract]
public class Trends
{
[DataMember(Name = "as_of")]
public string AsOf { get; set; }
//The As_OF value is returned - But how do I get the
//multidimensional array of Names and Queries from the JSON here?
}

I've run into this very issue while developing Twitterizer. The issue is that the dataset isn't in a traditional object-oriented design.
If you were to map that as objects, you would see:
object root
int as_of
object trends
array[object] <date value of as_of>
string query
string name
As you can see, the trend object has a property that's name changes. The name is based on the as_of date value. As such, it can't be automatically deserialized.
My first solution was to use System.Web.Script.Serialization.JavaScriptSerializer.DeserializeObject(). That method returns a hierarchy of weakly typed, nested dictionary instances. I then stepped through the results myself.
internal static TwitterTrendTimeframe ConvertWeakTrend(object value)
{
Dictionary<string, object> valueDictionary = (Dictionary<string, object>)value;
DateTime date = new DateTime(1970, 1, 1, 0, 0, 0).AddSeconds((int)valueDictionary["as_of"]);
object[] trends = (object[])((Dictionary<string, object>)valueDictionary["trends"])[date.ToString("yyyy-MM-dd HH:mm:ss")];
TwitterTrendTimeframe convertedResult = new TwitterTrendTimeframe()
{
EffectiveDate = date,
Trends = new Collection<TwitterTrend>()
};
for (int i = 0; i < trends.Length; i++)
{
Dictionary<string, object> item = (Dictionary<string, object>)trends[i];
TwitterTrend trend = new TwitterTrend()
{
Name = (string)item["name"]
};
if (item.ContainsKey("url"))
{
trend.Address = (string)item["url"];
}
if (item.ContainsKey("query"))
{
trend.SearchQuery = (string)item["query"];
}
convertedResult.Trends.Add(trend);
}
return convertedResult;
}
It's ugly, but it worked.
I've since embraced the use of Json.NET for it's speed and simplicity.

have you considered using JSON.net ?

Consider this example:
public struct TwitterResponse
{
public int32 as_of;
public Trend[] Trends;
}
public struct Trends
{
public String name;
public String query;
}
Trend[] obj = JavaScriptConvert.DeserializeObject<TwitterResponse>( res ).Trends;
Probably needs finetuning, but that's the general idea on how to do it.