I want to make addition using next object's property value in list.
Here is the sample code.
public class MyClass
{
public List<Model> modelList { get; set; }
public MyClass()
{
modelList = GetModelList();
}
public List<Model> GetModelList()
{
return new List<Model>
{
new Model(){Number = 1, Total = 0},
new Model(){Number = 2, Total = 0},
new Model(){Number = 3, Total = 0},
new Model(){Number = 4, Total = 0},
};
}
}
public class Model
{
public int Number { get; set; }
public int Total { get; set; }
}
In above case :
modelList[0].Total should be modelList[0].Number + modelList[1].Number
What could be the best way to achieve this ? Any help ?
Below is the code How I am achieving currently
for (int i = 0; i < modelList.Count - 1; i++)
{
modelList[i].Total = modelList[i].Number + modelList[i + 1].Number;
}
I added a method ComputeTotal to show a solution
public MyClass()
{
modelList = GetModelList();
modelList = ComputeTotal(modelList);
}
private List<Model> ComputeTotal(List<Model> models)
{
for (var i = 0; i < models.Count; i++)
{
var hasNext = (i + 1) < models.Count;
// no computation if hasNext is false
if (hasNext)
{
var currentNumber = models[i].Number;
var nextNumber = models[i + 1].Number;
models[i].Total = currentNumber + nextNumber;
}
}
return models;
}
i know this is very explicit. But it clearly demonstrates the approach.
Update:
added the hasNext check to avoid System.ArgumentOutOfRangeException: 'Index was out of range. Must be non-negative and less than the size of the collection.
Related
So I have a generic list of objects, and I need to combine their properties to get list of sums.
public class PickupReport
{
public int Units { get; set; }
public int Revenue { get; set; }
public int Accs { get; set; }
}
public class ReportBase<TReport>
{
public List<TReport> Reports { get; set; }
public List<int> Sum
{
get
{
return new List<int>{1,2,3}
}
}
}
So, if I have
var reportBase = new ReportBase<PickupReport>();
reportBase.Reports = new List<PickupReport>{
new PickupReport{Units = 1, Revenue = 2, Accs = 3},
new PickupReport{Units = 4, Revenue = 5, Accs = 6},
new PickupReport{Units = 2, Revenue = 3, Accs = 4}
}
I need to get and calculate reportBase.Sum and it should be List<int> with {7, 10, 13}
Like {the sum of property #1 for all objects, the sum of property #2 for all objects, and so on.. }
Is it possible to do this somehow, given that the number of objects in the list is dynamic? Well, the number of object properties, too, but within the class.
#MongZhu only int
Then I would suggest to use reflection for this approach. Make it a method rather then a property:
public class ReportBase<TReport>
{
public List<TReport> Reports { get; set; }
public IEnumerable<int> CalculateSum()
{
foreach (var element in typeof(TReport).GetProperties())
{
if (element.PropertyType == typeof(int))
{
yield return Reports.Sum(x => (int)element.GetValue(x));
}
}
}
}
Explanation:
This method iterates over all properties that are in the type and if it finds a property of type int it will calculate the sum of it from the entire list.
Here is a testprogramm and the result dump from LINQPad:
void Main()
{
var reportBase = new ReportBase<PickupReport>();
reportBase.Reports = new List<PickupReport>{
new PickupReport(1,2,3),
new PickupReport(4,5,6),
new PickupReport(2,3,4)
};
reportBase.CalculateSum().Dump();
}
EDIT:
just noticed, that objects in my project can have two types of properties, not one
Here is a version where you can add types to a list of allowed sum up types:
public class ReportBase<TReport>
{
public List<TReport> Reports { get; set; }
List<Type> possibleTypes = new List<Type> {typeof(int), typeof(double)};
public IEnumerable<double> CalculateSum()
{
foreach (PropertyInfo element in typeof(TReport).GetProperties())
{
if (possibleTypes.Contains(element.PropertyType))
{
yield return Reports.Sum(x => Convert.ToDouble(element.GetValue(x)));
}
}
}
}
Now you can also handle double
This should get you a List<int> with the sums of all int properties of TReport:
var properties = typeof(PickupReport).GetProperties();
List<int> sum = new List<int>();
for (int i = 0; i<properties.Length; ++i)
{
sum.Add(0);
if (properties[i].PropertyType == typeof(int))
{
foreach (var report in reportBase.Reports)
{
sum[i] += (int) properties[i].GetValue(report);
}
}
}
I'm trying to bind a linkedlist to a datagridview. The method below works for the properties in the class except the array.
If I declare the array as a new instance the linkedlist is created correctly, but the array is not bound into the datagridview.
If the array is created as a property (I think the code is correct) causes An unhandled exception of type 'System.StackOverflowException' occurred when the linkedlist is created.
Thanks for any help.
public class PayoffNode
{
public int DealNo { get; set; }
public string Category { get; set; }
public string Strategy { get; set; }
public string GreekType { get; set; }
// declare array as instance or as a property?
//public double[] Data = new double[22];
public double[] Data
{
get { return Data; }
set { Data = value; }
}
}
LinkedList<Globals.PayoffNode> PayLL = new LinkedList<Globals.PayoffNode>();
Random Rnd = new Random();
for (int K = 1; K <= 10; K++)
{
var T = new Globals.PayoffNode();
T.Category = "Account==" + K;
T.GreekType = "Greek==" + K;
T.DealNo = K;
T.Strategy = "Strategy==" + K;
for (int DP = 1; DP <= 21; DP++)
{
T.Data[DP] = Rnd.Next(10, 99);
}
PayLL.AddLast(T);
}
List<Globals.PayoffNode> qP = (from P in PayLL
where P.Category == "Account==4" && P.DealNo == 4 && P.GreekType == "Greek==4" && P.Strategy == "Strategy==4"
select P).ToList();
PayoffTable.DataSource = qP;
Update:
Thanks for the comments, this seems to be working.
public class PayoffNode
{
public int DealNo { get; set; }
public string Category { get; set; }
public string Strategy { get; set; }
public string GreekType { get; set; }
public double Data1 { get; set; }
public double Data2 { get; set; }
public double Data3 { get; set; }
public double[] Data = new double[22];
}
LinkedList<Globals.PayoffNode> PayLL = new LinkedList<Globals.PayoffNode>();
Random Rnd = new Random();
for (int K = 1; K <= 10; K++)
{
var T = new Globals.PayoffNode();
T.Category = "Account==" + K;
T.GreekType = "Greek==" + K;
T.DealNo = K;
T.Strategy = "Strategy==" + K;
for (int DP = 1; DP <= 21; DP++)
{
T.Data[DP] = Rnd.Next(10, 99);
}
PayLL.AddLast(T);
}
List<Globals.PayoffNode> qP = (from P in PayLL
where P.Category == "Account==4" && P.DealNo == 4 && P.GreekType == "Greek==4" && P.Strategy == "Strategy==4"
select new Globals.PayoffNode()
{
Category=P.Category,
DealNo=P.DealNo,
GreekType=P.GreekType,
Strategy=P.Strategy,
Data1=P.Data[1],
Data2 = P.Data[2],
Data3 = P.Data[3],
}).ToList();
PayoffTable.DataSource = qP;
One way to avoid making 21 Data properties is to convert the List to DataTable:
class PayoffNode
{
public int DealNo;
public string Category;
public double[] Data; // = new double[21];
}
and then
Random Rnd = new Random();
List<PayoffNode> PayLL = Enumerable.Range(1, 10).Select(i => new PayoffNode {
DealNo = i,
Category = "Account==" + i,
Data = Enumerable.Range(1, 21).Select(d => (double)Rnd.Next(10, 99)).ToArray()
}).ToList();
// List<PayoffNode> to DataTable
var dt = new DataTable();
dt.Columns.Add("DealNo", typeof(int));
dt.Columns.Add("Category"); // typeof(string) by default
for (int i = 1; i <= 21; i++)
dt.Columns.Add("Data" + i, typeof(double));
foreach (var P in PayLL)
{
var dr = dt.Rows.Add(P.DealNo, P.Category);
for (int i = 0; i < 21; i++)
dr[i+2] = P.Data[i]; // +2 is the number of fields before the Data fields
}
PayoffTable.DataSource = dt;
dt.DefaultView.RowFilter = " Category = 'Account==4' ";
The advantage is that you set the DataSource only once and just change the RowFilter to filter it. Also, any changes made in the DataGridView change the DataTable and vice-versa.
Note that arrays in C# and most other languages start from 0 and not from 1 ( .Data[0] to access the first item in the array ), so the for loop to access the Data array in my example is from 0 to 20.
public double[] Data
{
get { return Data; }
set { Data = value; }
}
This is the problem, the object in the set and get method needs to refer to a different object otherwise whenever the object value is set or trying to be retrieved it will just keep calling these methods infinitely. should be...
private double[] _data;
public double[] Data
{
get { return _data; }
set { _data = value; }
}
or...
public double[] Data { get; set; }
I have the following string:
string myString = "{'gridObject':'[1,2,3,4],[5,6,7,8]'}";
How do I process this into an object so that I can do this:
charts[0] //=> [1,2,3,4]
charts[0][1] //=> 2
If I can convert it to this object, even better:
public class gridObject {
public int datarow {get; set;}
public int datacol {get; set;}
public int datasizex {get; set;}
public int datasizey {get; set;}
}
This is what I would do.
Create your classes first,
public class GridObject
{
public int datarow { get; set; }
public int datacol { get; set; }
public int datasizex { get; set; }
public int datasizey { get; set; }
}
public class GridObjectCollection
{
public GridObject[] GridObjects { get; set; }
}
Then, to see what JSON you need, serialize it once: (JsonConvert is part of Json.NET, you can get it with NuGet)
GridObjectCollection gridObjects = new GridObjectCollection();
gridObjects.GridObjects = new GridObject[]
{
new GridObject() { datacol = 1, datarow = 2, datasizex = 3, datasizey = 4 },
new GridObject() { datacol = 5, datarow = 6, datasizex = 7, datasizey = 8 }
};
Console.WriteLine
(
JsonConvert.SerializeObject
(
gridObjects,
new JsonSerializerSettings() { Formatting = Formatting.Indented }
)
);
Here you can see that the valid JSON content which will produce these classes when deserialized is like:
{
"GridObjects": [
{
"datarow": 2,
"datacol": 1,
"datasizex": 3,
"datasizey": 4
},
{
"datarow": 6,
"datacol": 5,
"datasizex": 7,
"datasizey": 8
}
]
}
Then, just try a deserialization just to make sure:
var f = JsonConvert.DeserializeObject<GridObjectCollection>
(
"{'GridObjects':[{'datarow':2,'datacol':1,'datasizex':3,'datasizey':4},{'datarow':6,'datacol':5,'datasizex':7,'datasizey':8}]}"
);
Here is one way to do it:
public static gridObject[] Parse(string str)
{
int first = str.IndexOf("[");
int last = str.LastIndexOf("]");
str = str.Substring(first, last - first + 1);
string[] big_parts = str.Split(new string[] {"[", "],[", "]"} , StringSplitOptions.RemoveEmptyEntries);
return big_parts.Select(x =>
{
string[] small_parts = x.Split(',');
return new gridObject()
{
datarow = Convert.ToInt32(small_parts[0]),
datacol = Convert.ToInt32(small_parts[1]),
datasizex = Convert.ToInt32(small_parts[2]),
datasizey = Convert.ToInt32(small_parts[3]),
};
}).ToArray();
}
It first searches for the the first [ and the last ] and trims anything before [ and after ].
Then, it splits the string based on [, ],[, ].
This will give us 1,2,3,4 and 5,6,7,8 for your example.
Then for each one of them, we split based on , and convert the results into a gridObject object.
Done with custom parsing:
public class GridObject
{
public int datarow { get; set; }
public int datacol { get; set; }
public int datasizex { get; set; }
public int datasizey { get; set; }
}
/// <summary>
/// MySuperObject class which holds a reference to inner array of integers
/// </summary>
public class MySuperObject
{
public List<int> Items { get; set; } // Inner array of list of integers
public MySuperObject()
{
Items = new List<int>();
}
public override string ToString()
{
// Need to override ToString to return something like "[1,2,3,4]"
var result = "";
foreach (var item in Items)
{
if (result.Length > 0)
result += ",";
result += item.ToString();
}
return string.Format("[{0}]", result);
}
/// <summary>
/// Function to generate GridObject from existing set of integers
/// </summary>
public GridObject GetGridObject()
{
var result = new GridObject();
if (Items.Count >= 1) result.datarow = Items[0];
if (Items.Count >= 2) result.datacol = Items[1];
if (Items.Count >= 3) result.datasizex = Items[2];
if (Items.Count >= 4) result.datasizey = Items[3];
return result;
}
}
// Parse functions
public List<MySuperObject> Parse(string value)
{
if (string.IsNullOrEmpty(value))
throw new ArgumentException("value cannot be null or empty!", "value");
var result = new List<MySuperObject>();
// First get the indexes of first [ and last ]
var idxStart = value.IndexOf("[");
var idxEnd = value.LastIndexOf("]");
// Check validity
if (idxStart < 0 || idxEnd < 0 || idxEnd <= idxStart)
return result; // Return empty list
value = value.Substring(idxStart, idxEnd - idxStart + 1).Trim();
// Split by [] after replacing spaces with empty strings (and removing first and last [ and ])
var arr = value.Replace(" ", "").Trim('[',']').Split(new[] { "],[" }, StringSplitOptions.RemoveEmptyEntries);
foreach (var str in arr)
{
// Construct list of integers with a help of LINQ
var nums = str.Split(',').Select(t => Convert.ToInt32(t)).ToList();
// Create and add MySuperObject to existing list which will be returned
result.Add(new MySuperObject
{
Items = new List<int>(nums),
});
}
return result;
}
And here is the usage of such parsing:
var myString = "{'gridObject':'[1,2,3,4],[5,6,7,8]'}";
var value = Parse(myString);
// Get all grid objects
var allGridObjects = value.Select(t => t.GetGridObject()).ToList();
Of course, this could need a little bit more of error checking but basically, this MySuperObject is used to use any number of integers you desire, while providing you with a helper method of "GetGridObject" to fill you grid object with appropriate numbers from array of numbers.
class Program
{
static void Main(string[] args)
{
Posting onjPosting = null;
List<Posting> objList = null;
for (int i = 0; i < 100; i++)
{
onjPosting = new Posting();
onjPosting.Key1 = i;
for (int j = 0; j < 5; i++)
{
Choice objChoice = new Choice();
objChoice.ID = i;
objChoice.VAL = j;
onjPosting.GetPostingChoice.Add(objChoice); // GETTING ERROR [ Object reference not set to an instance of an object. ]
}
objList.Add(onjPosting);
}
}
}
public class Choice
{
public int ID { get; set; }
public int VAL { get; set; }
}
public class Posting
{
public int Key1 { get; set; }
public List<Choice> GetPostingChoice { get; set; }
}
While looping through and assigning the value I am getting error . How to solve this ? Please help me out .
My requirement is one parent class (Posting) , can contain number of data List .
Thanks in advance .
You never allocate the GetPostingChoice list so of course it is null.
You could do it in the constructor:
public class Posting
{
public Posting()
{
GetPostingChoice = new List<Choice>();
}
public int Key1 { get; set; }
public List<Choice> GetPostingChoice { get; set; }
}
Add a public constructor on your Posting class:
public class Posting
{
public int Key1 { get; set; }
public List<Choice> GetPostingChoice { get; set; }
public Posting()
{
GetPostingChoice = new List<Choice>();
}
}
You also have other errors:
You do not initialize objList, so you cannot add in there.
List<Posting> objList = null;
So you will get another Null Reference when you get to:
List<Posting> objList = null;
In your second loop you increase i instead of j so it will never end.
for (int j = 0; j < 5; i++)
This is how it should look:
Posting onjPosting = null;
List<Posting> objList = new List<Posting>();
for (int i = 0; i < 1; i++)
{
onjPosting = new Posting();
onjPosting.Key1 = i;
for (int j = 0; j < 5; j++)
{
Choice objChoice = new Choice();
objChoice.ID = i;
objChoice.VAL = j;
onjPosting.GetPostingChoice.Add(objChoice); // GETTING ERROR [ Object reference not set to an instance of an object. ]
}
objList.Add(onjPosting);
}
Since you ask for another approach, and this is just one of the many ways you could do it, have a look at this:
List<Posting> objList = new List<Posting>();
Enumerable.Range(0,100)
.Select
(
(x,i)=>new Posting
{
Key1 = i,
GetPostingChoice = Enumerable.Range(0,5).Select((p,j)=>new Choice{ID = i,VAL = j}).ToList()
}
);
I have 2 List collections. One contains numbers, the other names. There are twice as many numbers as names(always). I want to take the first name from the collection and the first two numbers from the other collection then put them together in a 3rd user collection of (VentriloUser). Then the second name needs to be matched with the 3rd and 4th numbers and so on.
I was thinking something with a for or foreach loop, but I can't wrap my head around it right now.
public class VentriloUser
{
public VentriloUser(string name, int seconds, int ping)
{
Name = name; Seconds = seconds; Ping = ping;
}
public string Name { get; set; }
public int Ping { get; set; }
public int Seconds { get; set; }
}
public class Ventrilo
{
public Ventrilo(string statusurl)
{
StatusURL = statusurl;
}
public string StatusURL { get; set; }
public string HTML { get; set; }
public List<VentriloUser> Users { get; set; }
private Regex findNumbers = new Regex("\\<td width=\"10%\" bgcolor=\"#\\w{6}\"\\>\\<font color=\"#000000\">\\<div style=\"overflow:hidden;text-overflow:ellipsis\"\\>-?\\d+\\<");
private Regex findNames = new Regex("\\<td width=\"20%\" bgcolor=\"#\\w{6}\"\\>\\<font color=\"#000000\">\\<div style=\"overflow:hidden;text-overflow:ellipsis\"\\>\\b\\w+\\<");
private WebClient wClient = new WebClient();
public void DownloadHTML()
{
HTML = wClient.DownloadString(StatusURL);
}
public List<int> GetNumbers()
{
var rawnumbers = findNumbers.Matches(HTML);
var numbers = new List<int>();
foreach (var rawnumber in rawnumbers)
{
var match = Regex.Match(rawnumber.ToString(), "\\>\\-?\\d+\\<");
string number = Regex.Replace(match.ToString(), "\\<|\\>", "");
numbers.Add(Convert.ToInt32(number));
}
return numbers;
}
public List<string> GetNames()
{
var rawnames = findNames.Matches(HTML);
var names = new List<string>();
foreach (var rawname in rawnames)
{
var match = Regex.Match(rawname.ToString(), "\\>\\w+<");
string name = Regex.Replace(match.ToString(), "\\<|\\>", "");
names.Add(name);
}
return names;
}
public List<VentriloUser> GenerateUsers()
{
var numbers = GetNumbers();
var names = GetNames();
var users = new List<VentriloUser>();
}
}
I am a hobbyist, but hope to pursue a career one day. Any help is much appreciated. Thank you for your time.
Using LINQ:
var users = names.Select((name,idx) => new VentriloUser(name, numbers[idx*2], numbers[idx*2+1]))
.ToList();
Using loops:
var users = new List<VentriloUser>();
for (int i = 0; i < names.Count; i++)
{
var name = names[i];
int j = i * 2;
if (j >= numbers.Count - 1)
break; // to be safe...
users.Add(new VentriloUser(name, numbers[j], numbers[j + 1]));
}