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1. Top results related to how to initialize a dictionary in c# with statement

   • Initialize a Dictionary with values in C# 2.0

     Top Answer

     Answered Jul 19, 2013 · 10 votes

     But it doesn't work in C# 2.0. Is there any workaround for this without using Add or basing on an already existing collection?

     No. The closest I can think of would be to write your own DictionaryBuilder type to make it simpler:

     public class DictionaryBuilder<TKey, TValue>{ private Dictionary<TKey, TValue> dictionary = new Dictionary<TKey, TValue> dictionary(); public DictionaryBuilder<TKey, TValue> Add(TKey key, TValue value) { if (dictionary == null) { throw new InvalidOperationException("Can't add after building"); } dictionary.Add(key, value); return this; } public Dictionary<TKey, TValue> Build() { Dictionary<TKey, TValue> ret = dictionary; dictionary = null; return ret; }}

     Then you can use:

     Dictionary<string, int> x = new DictionaryBuilder<string, int>() .Add("Foo", 10) .Add("Bar", 20) .Build();

     This is at least a single expression still, which is useful for fields where you want to initialize at the point of declaration.

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     1/5

   • In C#: How to declare a generic Dictionary with a type as key and an IEnumerable<> of that type as value?

     Top Answer

     Answered Dec 01, 2017 · 21 votes

     You may not even need a dictionary to be able to do this - but that depends on your needs. If you only ever need 1 such list per type per appdomain (i.e. the "dictionary" is static), the following pattern can be efficient and promotes type-inference nicely:

     interface IBase {}-static class Container { static class PerType<T> where T : IBase { public static IEnumerable<T> list; } public static IEnumerable<T> Get<T>() where T : IBase => PerType<T>.list; public static void Set<T>(IEnumerable<T> newlist) where T : IBase => PerType<T>.list = newlist; public static IEnumerable<T> GetByExample<T>(T ignoredExample) where T : IBase => Get<T>(); }

     Note that you should think carefully before adopting this approach about the distinction between compile-time type and run-time type. This method will happily let you store a runtime-typed IEnumerable<SomeType> variable both under SomeType and -if you cast it- under any of SomeType's base types, including IBase, with neither a runtime nor compiletype error - which might be a feature, or a bug waiting to happen, so you may want an if to check that.

     Additionally, this approach ignores threading; so if you want to access this data-structure from multiple threads, you probably want to add some locking. Reference read/writes are atomic, so you're not going to get corruption if you fail to lock, but stale data and race conditions are certainly possible.

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     2/5

   • How to initialize a double array with various values using switch case in C#

     Top Answer

     Answered Jul 15, 2015 · 0 votes

     You were close, you just have to use new to initialize the arrays:

     double [] test1; int value; // Which I will get it from DBSwitch (value){case 1: test1 = new double[] {1, 0, 0,1}; break;case 2: test1 = new double[] {0, 0, 0,1}; break;case 3: test1 = new double[] {0, 0, 1,1}; break;case 4: test1 = new double[] {1, 0, 1,1}; break;}

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     3/5

   • How to use a switch case statement in conjunction with a group box in c#?

     Top Answer

     Answered Mar 18, 2022 · 1 votes

     If you are still stuck and you are using Windows Forms, I would suggest subscribing to the CheckedChanged event either in the properties inspector or in the code behind for each of the radio buttons you have in your groupbox. Switching on the Text Property of the RadioButton is one way of achieving this in the event.

     In your initialisation code:

     OptSchlafen.CheckedChanged += SomeFunctionToCheckChangedState;

     and in your code a function:

     private void SomeFunctionToCheckChangedState(object sender, EventArgs e){ // Insert your check logic here switch((sender as RadioButton).Text) { case "radiobuttontext": //what you want to do goes here break; }}

     When you click the radio button this event will be fired and the function called.

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     4/5

   • How to initialize an array with numbers separated by a specific interval in C#

     Top Answer

     Answered Feb 22, 2012 · 18 votes

     An interesting fact is that every answer posted so far has fixed the bug in your proposed code, but only one has called out that they've done so.

     Binary floating point numbers have representation error when dealing with any quantity that is not a fraction of an exact power of two. ("3.0/4.0" is a representable fraction because the bottom is a power of two; "1.0/10.0" is not.)

     Therefore, when you say:

     for(i = 0; i < 10; i++) { myArray[i] = increment; increment += 0.1; }

     You are not actually incrementing "increment" by 1.0/10.0. You are incrementing it by the closest representable fraction that has an exact power of two on the bottom. So in fact this is equivalent to:

     for(i = 0; i < 10; i++) { myArray[i] = increment; increment += (exactly_one_tenth + small_representation_error);}

     So, what is the value of the tenth increment? Clearly it is 10 * (exactly_one_tenth + small_representation_error) which is obviously equal to exactly_one + 10 * small_representation_error. You have multiplied the size of the representation error by ten.

     Any time you repeatedly add together two floating point numbers, each subsequent addition increases the total representation error of the sum slightly and that adds up, literally, to a potentially large error. In some cases where you are summing thousands or millions of small numbers the error can become far larger than the actual total.

     The far better solution is to do what everyone else has done. Recompute the fraction from integers every time. That way each result gets its own small representation error; it does not accumulate the representation errors of previously computed results.

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2. stackoverflow.com › questions › 17047602Proper way to initialize a C# dictionary with values

   stackoverflow.com › questions › 17047602

   • Cached

   See How to initialize a dictionary with a collection initializer (C# Programming Guide) for details.

   Code sample

   var myDict = new Dictionary<string, string> {

     { "key1", "value1" },

     { "key2", "value2" }

   };

   Console.ReadKey();...

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3. learn.microsoft.com › en-us › dotnetHow to initialize a dictionary with a collection initializer - C#

   learn.microsoft.com › en-us › dotnet

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   • Overview
   • Example
   • See also

   A Dictionary contains a collection of key/value pairs. Its Add method takes two parameters, one for the key and one for the value. One way to initialize a Dictionary , or any collection whose Add method takes multiple parameters, is to enclose each set of parameters in braces as shown in the following example. Another optio...

   See full list on learn.microsoft.com

   In the following code example, a Dictionary is initialized with instances of type StudentName. The first initialization uses the Add method with two arguments. The compiler generates a call to Add for each of the pairs of int keys and StudentName values. The second uses a public read / write indexer method of the Dictionary class:

   Note the two pairs of braces in each element of the collection in the first declaration. The innermost braces enclose the object initializer for the StudentName, and the outermost braces enclose the initializer for the key/value pair that will be added to the students Dictionary . Finally, the whole collection initializer for the dictionary is enclosed in braces. In the second initialization, the left side of the assignment is the key and the right side is the value, using an object initializer for StudentName.

   See full list on learn.microsoft.com

   •C# Programming Guide

   •Object and Collection Initializers

   See full list on learn.microsoft.com

4. www.techiedelight.com › initialize-dictionary-csharpInitialize a Dictionary in C# - Techie Delight

   www.techiedelight.com › initialize-dictionary-csharp

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   Apr 6, 2024 · This post will discuss how to initialize a dictionary in C#... To initialize a dictionary, we can enclose each set of key-value in curly braces. Internally for each pair, the compiler makes a call to Dictionary's `Add()` method.

5. stackoverflow.com › questions › 55589251smartest way to initialize dictionary in c# - Stack Overflow

   stackoverflow.com › questions › 55589251

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   Apr 9, 2019 · It could mean that we should try to assign a two dimensional array to the Dictionary<string, object> property. If the compiler was "smart" and interpreted this as a Dictionary, when there is another possible meaning of the statement, the compiler would so to say become coauthor of your code.

6. makolyte.com › csharp-initialize-a-dictionaryC# - Initialize a dictionary | makolyte

   makolyte.com › csharp-initialize-a-dictionary

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   Sep 12, 2023 · C# – Initialize a dictionary. You can declare a dictionary and initialize it with values by using the collection initializer syntax. Within the initializer block, you have two options for adding key/value pairs to the dictionary: Indexer syntax, like [key] = value. Curly brace syntax, like { key, value }. I’ll show examples of both options ...

7. puzzledbycsharp.com › dictionary › how-to-initializeHow To Initialize A Dictionary In C# - puzzledbycsharp.com

   puzzledbycsharp.com › dictionary › how-to-initialize

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   C# provides Collection Initializers syntax to initialize dictionaries to simple, quick, and readable code.

8. People also ask

   How to initialize a dictionary with values?

   • You can declare a dictionary and initialize it with values by using the collection initializer syntax. Within the initializer block, you have two options for adding key/value pairs to the dictionary: Indexer syntax, like [key] = value. Curly brace syntax, like { key, value }. I’ll show examples of both options below.

   C# - Initialize a dictionary | MAKOLYTE

   makolyte.com/csharp-initialize-a-dictionary/

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   How to initialize a dictionary in C#?

   • In the second initialization, the left side of the assignment is the key and the right side is the value, using an object initializer for StudentName. Learn how to initialize a dictionary in C#, using either the Add method or an index initializer. This example shows both options.

   How to initialize a dictionary with a collection initializer - C#

   learn.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/how-to-initialize-a-dictionary-with-a-collection-initializer

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   How to initialize a dictionary in JavaScript?

   • There are two ways to use the Collection Initializer. The first way is called the add Collection Initializer and the second is Index Initializer. This lets you Initialize the dictionary on the same line as the declaration statement. The interesting thing is when this syntax is compiled.

   How To Initialize A Dictionary In C#

   puzzledbycsharp.com/dictionary/how-to-initialize-a-dictionary/

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   How do I initialize a dictionary at compile time?

   • C# offers several ways to initialize a dictionary at compile time. Because oftentimes there's a dictionary that you just want to hold a few values for some look-ups for other structures in the code. It may not change so it can be set and left alone. So C# offers the collection initializers to quickly do this where the dictionary itself is declared.

   How To Initialize A Dictionary In C#

   puzzledbycsharp.com/dictionary/how-to-initialize-a-dictionary/

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9. www.gyata.ai › c-sharp › c-initialize-dictionaryGuide to Initialize a Dictionary in C# | C# Tutorial

   www.gyata.ai › c-sharp › c-initialize-dictionary

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   Dec 8, 2023 · The simplest way to initialize a dictionary in C# is to create an empty dictionary. The following code illustrates how to do this: