c#,arrays,string,list , How create many list as array?


How create many list as array?

Question:

Tag: c#,arrays,string,list

I have a problem on creating a set of list in array

this is my coding but it's wrong one, any correction for this?

List<string>[] item = new List<string>[10]();

I want to create 10 list in string named as item but I can't do it

and then how can I store more than 1 element in each of the 10 item list??

item[1].add(a);     //when I want to print that a I use item[1][0]
item[1].add(b);     //when I want to print that b I use item[1][1]

item[2].add(aa);
item[2].add(bb);

but how can I store element in each of the list?


Answer:

If you KNOW for certain that you want exactly ten lists, you can use an array instantiated to 10 items, each a list of string.

List<string> [] items = new List<string> [10];

Each List is not initialized, so you need to initialize your list before you can use it and each list can be accessed via normal indexer syntax..

if (items[0] == null)
    items[0] = new List<string>();

Once initialized, you can fill in your data.

items[0].Add("another string");

If you wanted to pre-initialize each list so that you do not get a NullReferenceException, do so in a loop.

for (var i = 0; i < items.Length; i++)
    items[i] = new List<string>();

However, if you think that your items may need to hold more List<string> down the road, just simply use a list of lists.

List<List<string>> items = new List<List<string>>();

List wraps array and gives you some nice syntactic sugar and optimizations for expanding arrays which makes your life a lot easier. You can still use indexer syntax to access each list within your list.

if (items[0] == null)
    items[0] = new List<string>();

items[0].Add("another string").

Related:


Convert contents of an XmlNodeList to a new XmlDocument without looping


c#,xml,xpath,xmldocument,xmlnodelist
I have Xml that I filter using XPath (a query similar to this): XmlNodeList allItems = xDoc.SelectNodes("//Person[not(PersonID = following::Person/PersonID)]"); This filters all duplicates from my original Persons Xml. I want to create a new XmlDocument instance from the XmlNodeList generated above. At the minute, the only way I can see...

Marshal struct in struct from c# to c++


c#,c++,marshalling
I have the following structures in C# and C++. C++: struct TestA { char* iu; }; struct TestB { int cycle1; int cycle2; }; struct MainStruct { TestA test; TestB test2; }; C#: [StructLayout(LayoutKind.Sequential, CharSet=CharSet.Ansi, Pack = 1)] internal struct TestA { [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 36)] private string iu; public...

How to pivot array into another array in Ruby


arrays,ruby,csv
I have a multidimensional array like this one : myArray = [["Alaska","Rain","3"],["Alaska","Snow","4"],["Alabama","Snow","2"],["Alabama","Hail","1"]] I would like to end up with CSV output like this. State,Snow,Rain,Hail Alaska,4,3,nil Alabama,2,nil,1 I know that to get this outputted to CSV the way I want it I have to have output array like this: outputArray =[["State","Snow","Rain","Hail"],["Alaska",4,3,nil],["Alabama",2,nil,1]]...

SQL Server / C# : Filter for System.Date - results only entries at 00:00:00


c#,asp.net,sql-server,date,gridview-sorting
I have a connected SQL Server database in Visual Studio and am displaying its content in a grid. I created a dropdown menu with the column names as selectable options and a text field to filter for specific content, e.g., DropDown = "Start" - Textfield = 14.03.2015 = Filter Column...

Memory consumption when chaining string methods


c#,string,immutability,method-chaining
I know that string in C# is an immutable type. Is it true that when you chain string functions, every function instantiates a new string? If it is true, what is the best practice to do too many manipulations on a string using chaining methods?...

Javascript function to validate contents of an array


javascript,arrays
Here's what is asked: validItems(items) – this function receives a string array of items which are to be for a customer. The function returns an empty string indicating all item codes in the array are valid; otherwise the function returns the first invalid item code in the array. All item...

Catch concurrency exception in EF6 to change message to be more user friendly


c#,asp.net,.net,entity-framework,entity-framework-6
I am using EF6.1 and i would like to change the message to a more system specific message when the below exception is thrown. Store update, insert, or delete statement affected an unexpected number of rows (0) Now, my problem is i cannot seem to catch the exception? I have...

How to declare var datatype in public scope in c#?


c#,linq
I write simple query with linq to sql : var query = (from p in behzad.GAPERTitles select new { p.id, p.gaptitle }).ToArray(); up code into the c# windows application ,windows form load event,and i want use up result into the button click event in this scope: private void button1_Click(object sender,...

How do I provide a collection of elements to a custom attached property?


c#,wpf,binding
I found a few examples online, and a few questions and answers here, but I just can't get it to work. I need a custom attached property that can take one or more target elements. For example... <ListView> <dd:MyDragDrop.DropBorders> <Binding ElementName="brdOne"/> <Binding ElementName="brdTwo"/> <Binding ElementName="brdThree"/> </dd:MyDragDrop.DropBorders> </ListView> I've also had...

Blank screen on GridView


android,arrays,gridview
I'm trying to create a GridView with an array of strings. These are XML, and MainActivity and Adapter, but what I get is a blank screen. I'm change the background, but the result is the same, but clicking on a point on the screen appears to me the toast stating...

Load XML to list using LINQ [duplicate]


c#,xml,linq
This question already has an answer here: XDocument to List of object 1 answer I have following XML: <?xml version="1.0" encoding="utf-8"?> <start> <Current CurrentID="5"> <GeoLocations> <GeoLocation id="1" x="78492.61" y="-80973.03" z="-4403.297"/> <GeoLocation id="2" x="78323.57" y="-81994.98" z="-4385.707"/> <GeoLocation id="3" x="78250.57" y="-81994.98" z="-4385.707"/> </GeoLocations> <Vendors> <Vendor id = "1" x="123456" y="456789" z="0234324"/>...

Substring of a file


javascript,arrays,substring
I have a file that is structure like this : var file = "a|b|c|d, a|b|c|d, a|b|c|d, a|b|c|d, a|b|c|d"; Now I would extract all letters "c" and "d" of this file and put those letter in array, structure like this: var array = [ [a,b,1], [a,b,2], [a,b,3], [a,b,4], [a,b,5] ]; How...

array and function php


php,arrays
I'm just a beginner in PHP coding. I've been reading through a tutorial, but having some trouble with basic PHP concepts. If you could help me, I'd be much obliged. I'm having trouble understanding why the following code doesn't work. <?php function sum($x, $y) { $z = $x + $y;...

Validate a field only if it is populated


c#,wpf,idataerrorinfo
I am having a problem with validating phone numbers. In our system we have two phone numbers which you can store. The problem I am having is that these are optional fields. So I want it to validate the phone number IF and only IF the user has tried to...

check if file is image


c#,asp.net,asp.net-mvc
I want to check if file is image. and then you will see a link where you can see the image. But the link only has to appear if file is link. I try it like this: if (!String.IsNullOrEmpty(item.FileName)) { var file = item.FileName; string[] formats = new string[] {...

Javascript sort array of objects in reverse chronological order


javascript,arrays,sorting
I have an array of objects which holds a list of jobs and I would like to sort them in reverse chronological order as they would appear on a resume for example. I came up with the below solution which 'seems' to work but I was wondering if there is...

How to Customize Visual Studio Setup


c#,visual-studio,setup-project
I have created a video chat application in c#. Now I wan to make a setup of it. I have created a setup using Visual studio's setup project but my client told me to customize the setup progress bar styles and other properties. i dont know how to do it....

How to return result while applying Command query separation (CQS)


c#,design-patterns,cqrs,command-query-separation
I am separating my query and command on service side like this: public class ProductCommandService{ void AddProduct(Product product); } public interface ProductQueryService{ Product GetProduct(Guid id); Product[] GetAllProducts(); } Command Query Separation accepts that a method should change state or return a result. There is no problem. public class ProductController: ApiController{...

Regex that allow void fractional part of number


c#,regex
@"[+-]?\d+(\.\d+)?" -this is a regex I have wrote for numbers it allows [+-] minus before the number digits before and digits after the point the question is how to change this to allow "not finished" values so that input of "5." - is fine too ?...

Update list of items in c#


c#,linq,list,updates
I would like to know if you can suggest me an efficient way to update a list of items in c#. Here is a generic example: If CurrentList is [ {Id: 154, Name: "George", Salary: 10 000} {Id: 233, Name: "Alice", Salary: 10 000}] And NewList is [ {Id: 154,...

pointer to pointer dynamic array in C++


c++,arrays,pointers
I've been having bad luck with dynamic pointers when I want to close it. why the application wrote to memory after end of heap buffer? how can I close my array? int main() { . . int **W; W = new int* [n]; for (int i=1; i <= n; i++)...

How to send Ctrl+S through SendKeys.Send() method to save a file(save as dialog)


c#,.net,windows,sendkeys
I need to save a file which is in an External application using SendKeys.Send() method. The keys needed to be sent are Ctrl+S. I wrote the below code, but its not working: SendKeys.SendWait("^%s?"); // to get the Save As dialog Thread.Sleep(5000); SetForegroundWindow(FindWindow(null, "Save As")); Thread.Sleep(5000); SendKeys.SendWait("xyz"); // Sending FileName ...

Aligning StackPanel to top-center in Canvas


c#,wpf,xaml,canvas
I'm trying to create an application which is supposed to measure quick reaction performance of it's user. The application starts up in full-screen mode and resizes it's elements accordingly to the screen resolution. The project was strongly inspired by training_aim_csgo2 map. It's mostly done, but here is the problem: I...

Access manager information from Active Directory


c#,asp.net,active-directory
Attach is the picture of active directory, which i got from my IT department. Now i want to get the manager information in C#. NOTE: I am able to get all information of user but there isn't any key of manager, but IT department just gave me above attached...

Get elements containing text from array


javascript,jquery,html,arrays,contains
I want to search all the elements containing any string in the array. For example I have following list of items <ul> <li>cricket bat</li> <li>tennis ball</li> <li>golf ball</li> <li>hockey stick</li> </ul> and this array var arr = ['bat', 'ball']; It should select all the elements having text bat and ball....

Infinite loop with fread


c,arrays,loops,malloc,fread
I'm trying to allocate an array 64 bytes in size and then loop over the array indexes to put a read a byte each from the inputfile. but when I don't malloc() the array indexes, the loop stays in index0 (so each time it loops it replaces the content in...

C# PCL HMACSHAX with BouncyCastle-PCL


c#,bouncycastle,portable-class-library
I want to implement this logic in portable C# class: static JsonWebToken() { HashAlgorithms = new Dictionary<JwtHashAlgorithm, Func<byte[], byte[], byte[]>> { { JwtHashAlgorithm.HS256, (key, value) => { using (var sha = new HMACSHA256(key)) { return sha.ComputeHash(value); } } }, { JwtHashAlgorithm.HS384, (key, value) => { using (var sha = new...

C# Code design / Seperate classes for each TabControl


c#,oop,architecture,software-design,code-design
My main problem is that my tool grows and grows and I start loosing the focus on the different parts of my code. The main-Form got a docked tabControl at fullsize. I got 5 different tabs with for really different functions. So I can say my tool is splitted into...

Get object by attribute value [duplicate]


c#,reflection,custom-attributes,spring.net
This question already has an answer here: How enumerate all classes with custom class attribute? 4 answers I have a set of classes which implement a common interface and are annotated with a business domain attribute. By design, each class is annotated with different parametrization [Foo(Bar=1)] public class EntityA...

how can I add a column to IQueryable object and modify its values


c#,.net,linq,grid,devexpress
var packs = from r in new XPQuery<Roll>(session) select new { Number = r.number Selection = new bool() }; gcPack.DataSource = packs; I want to add another column to my grid control with: Selection = new bool(). It will be added to the grid but I can't change its...

Difference between application and module pipelines in Nancy?


c#,asp.net,nancy
I have seen in the documentation of Nancy, sometimes these two are referred distinctively. And also is there a difference in the Before/After hooks of these two pipelines?...

Merge and sum values and put them in an array


javascript,arrays,angularjs,foreach
I'm retrieving values from an external source and apply a foreach loop to the results, with the code below. angular.forEach(data, function(value, key) { if (value.start_date > firstdayOfWeek && value.start_date < lastdayOfWeek) { console.log(value.firstname + ' - ' + value.distance); } else { //do nothing } }); The result is console...

System.net.http.formatting causing issues with Newtonsoft.json


c#,asp.net,asp.net-mvc,json.net
My Windows service is in the same solution as a MVC project. The MVC project uses a reference to SignalR Client which requires Newtonsoft.Json v6 + the Windows service uses System.Net.Http.Formatting, which requires Newtonsoft.Json version 4.5.0.0. I assumed this would not be a problem, as I could just use a...

C# XML: System.InvalidOperationException


c#,xml
I have been learning C#'s XML with a project however I keep getting the InvalidOperationException. I have put the code below XmlTextWriter writer = new XmlTextWriter(path, System.Text.Encoding.UTF8); writer.WriteStartDocument(true); writer.Formatting = Formatting.Indented; writer.Indentation = 4; writer.WriteStartElement("User Info"); writer.WriteStartElement("Name"); writer.WriteString(userName); writer.WriteEndElement(); writer.WriteStartElement("Tutor Name"); writer.WriteString(tutorName); writer.WriteEndElement();...

Is it possible to concactenate a DataBound value with a constant string in XAML DataBinding?


c#,xaml,windows-phone
To bind a value to a TextBlock we use the following syntax to display an <ItemName> property of a bounded object. <TextBlock Text="{Binding Path=ItemName}" /> But is there a syntax to use the above tag to concatenate the constant string 'Item' with the databounded property, in order display something like:...

Why is the task is not cancelled when I call CancellationTokenSource's Cancel method in async method?


c#,asynchronous,task,cancellationtokensource,cancellation-token
I created a small wrapper around CancellationToken and CancellationTokenSource. The problem I have is that the CancelAsync method of CancellationHelper doesn't work as expected. I'm experiencing the problem with the ItShouldThrowAExceptionButStallsInstead method. To cancel the running task, it calls await coordinator.CancelAsync();, but the task is not cancelled actually and doesn't...

while Inherit style in WPF it affect parent style


c#,xaml,styles,wpf-controls
In WPF i have a style for the control like below, <Style TargetType="local:CustomControl"> <Setter Property="Background" Value="Transparent" /> <Setter Property="BorderBrush" Value="Gray" /> <Setter Property="BorderThickness" Value="0,0,0,1" /> <Setter Property="Padding" Value="3,0,3,0" /> <Setter Property="IsTabStop" Value="False" /> <Setter Property="VerticalContentAlignment" Value="Center" /> </Style> Now i need to override customcontrol border for some other place like...

Translating a character array into a integer string in C++


c++,arrays,string
I was trying to achieve translating a character array into a integer string and corresponding character to their alphabetical order. For instance: A(a) = 0 , Z(z) = 25. string key_char = argv[1]; string key_num; for (int i = 0; i < key_char.length(); i++){ if (isalpha(key_char[i])){ if (islower(key_char[i])){ key_num[i] =...

Regex to remove `.` from a sub-string enclosed in square brackets


c#,.net,regex,string,replace
I have this regex in C#: \[.+?\] This regex extracts the sub-strings enclosed between square brackets. But before doing that I want to remove . inside these sub-strings. For example, the string hello,[how are yo.u?]There are [300.2] billion stars in [Milkyw.?ay]. should become hello,[how are you?]There are [3002] billion stars...

Collect strings after a foreach loop


c#,xml,foreach
Is it possible to collect the strings after a foreach loop? For example: StringCollection col = new StringCollection(); XmlNodeList skillNameNodeList=SkillXML.GetElementsByTagName("name"); foreach (XmlNode skillNameNode in skillNameNodeList) { skillsName=skillNameNode.Attributes["value"].Value; } col.Add(skillsName); //Return System.Collections.Specialized.StringCollection I want to collect each skillsName and put them in a collection or a list so that I can...

Ruby: How to copy the multidimensional array in new array?


ruby-on-rails,arrays,ruby,multidimensional-array
seating_arrangement [ [:first, :second, :none], [:first, :none, :second], [:second, :second, :first], ] I need to copy this array into new array. I tried to do it by following code: class Simulator @@current_state def initialize(seating_arrangement) @@current_state = seating_arrangement.dup end But whenever I am making any changes to seating_arrangement current_state changes automatically....

Foreign key in C#


c#,sql,sql-server,database
I have two tables, A and B, in a dataset in SQL Server; I have created a connection to the dataset in a c# project in visual studio. How can I create a foreign key ( A is the parent) between my two tables ? I want to create the...

Index was out of range. Must be non-negative or less than size of collection [duplicate]


c#
This question already has an answer here: What is an “index out of range” exception, and how do I fix it? [duplicate] 1 answer Trying to run a delete application in C#. If there is more than 10 files in a directory, delete the oldest file, and iterate again....

Create array from another with specific indices


javascript,arrays
I have two arrays, one of data and one of indices: var data = [ 'h', 'e', 'l', 'l', 'o', ' ' ]; var indices = [ 4, 0, 5, 0, 1, 2, 2 ]; I would like to create a third array, using cells of data in order indicated...

deployment of a site asp.net and iis


c#,asp.net,iis
I know this is for some of you a stupid question but for me is a real problem. I have never deployed a site before What i have done so far: 1) publish the site from visual studio to a folder. 2) added to iis for testing everything works great...

How can I determine if an object of anonymous type is empty?


c#,.net
I am sure the answer to this is quite simple but I am trying to write an if statement (C# 5.0) to determine whether or not an anonymous type is empty or not. Here is a simplified version of my code: public void DoSomething(object attributes) { // This is the...

Multiple Threads searching on same folder at same time


c#,multithreading,file-search
Currently I have a .txt file of about 170,000 jpg file names and I read them all into a List (fileNames). I want to search ONE folder (this folder has sub-folders) to check if each file in fileNames exists in this folder and if it does, copy it to a...

Visual Studio Assembly force-installs Target Framework


c#,.net,visual-studio-2013,.net-framework-version
I have this Assembly targeted at .NET 3.5. The code will work on later versions as well, but I like this to work on Windows XP. I mean, .NET is backwards compatible, right? I can run apps for .NET 3.5 on Windows 8.1. However, when I run my own assembly,...

Convert Date Time to IST


c#
I want to convert the date time to "Indian Standard Time", so i used the following code :- public static TimeZoneInfo INDIAN_ZONE = TimeZoneInfo.FindSystemTimeZoneById("Indian Standard Time"); writer.WriteLine("{0} {1}", indianTime.ToLongTimeString(), indianTime.ToLongDateString()); The above code gives me error :- System.TimeZoneNotFoundException: The time zone ID 'Indian Standard Time' was not found on the...