Proper way to initialize a C# dictionary with values already in it?
I am creating a dictionary in a C# file with the following code:
private readonly Dictionary<string, XlFileFormat> FILE_TYPE_DICT
= new Dictionary<string, XlFileFormat>
{
{"csv", XlFileFormat.xlCSV},
{"html", XlFileFormat.xlHtml}
};
There is a red line under new with the error:
Feature 'collection initilializer' cannot be used because it is not part of the ISO-2 C# language specification
Can anyone explain what is going on here?
EDIT: okay, so it turns out I was using .NET version 2.
I can't reproduce this issue in a simple .NET 4.0 console application:
static class Program
{
static void Main(string[] args)
{
Dictionary<string, string> myDict = new Dictionary<string, string>
{
{ "key1", "value1" },
{ "key2", "value2" }
};
Console.ReadKey();
}
}
Can you try to reproduce it in a simple Console application and go from there? It seems likely that you're targeting .NET 2.0 (which doesn't support it) or client profile framework, rather than a version of .NET that supports initialization syntax.
With C# 6.0, you can create a dictionary in following way:
var dict = new Dictionary<string, int>
{
["one"] = 1,
["two"] = 2,
["three"] = 3
};
It even works with custom types.
You can initialize a Dictionary (and other collections) inline. Each member is contained with braces:
Dictionary<int, StudentName> students = new Dictionary<int, StudentName>
{
{ 111, new StudentName { FirstName = "Sachin", LastName = "Karnik", ID = 211 } },
{ 112, new StudentName { FirstName = "Dina", LastName = "Salimzianova", ID = 317 } },
{ 113, new StudentName { FirstName = "Andy", LastName = "Ruth", ID = 198 } }
};
See MSDN for details.
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