C# Convert Data Types

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A List is not an array. This is not a problem unless you need an array. Conversions are possible for both simple values and complex data types. These conversions are sometimes complicated and involved. They rely on the C# language type system.

Overview: These C# examples show how to convert types. These conversions are more complex than casts.

Example

The C# language features many types, and sometimes you must change one type, such as an array, to another type, such as a List. In this example program, we use the System.Linq namespace to convert an int[] array into a List<int>.

Program that converts array to List [C#]

using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main()
    {
	int[] array = { 1, 2, 3 };
	List<int> list = array.ToList();
	Console.WriteLine(array[0] == list[0]);
	Console.WriteLine(array.Length == list.Count);
    }
}

Output

True
True

Arrays

Some of the more complicated conversion methods involve an array type. These articles demonstrate how you can convert various types, such as ArrayList, string, and List, into arrays and back again.

Lists

Another common task is converting to and from the List type in the C# language. These articles demonstrate how you can do this reliably, by providing many different examples.

Numbers

Most numeric conversions involve a multiplication or division expression. They can be tested using the Google search engine. These examples show how you can convert different units of measurement reliably.

Bools. You cannot convert bools and ints directly in the C# programming language. Instead, you must use expressions to convert them as needed.

Strings

These tutorials provide examples for string-specific conversions. There are other string conversions available in this category as well.

BitConverter

The BitConverter type in the C# language provides a way to convert byte arrays into integral value types, and the opposite. This tutorial helps you discover and use the BitConverter type.

Value types

Value types, such as the TimeSpan struct, can be converted into long values. Additionally, the Convert type also provides ways to convert values to Int32 with Convert.ToInt32.

Implicit/explicit

You can define conversion operators in the C# programming language. These work at the level of the language to convert one type to another. Implicit conversions require no special syntax. Explicit conversions require a cast expression.

Summary

For some types and collections, custom conversion methods as shown above are necessary. For simpler value types, using a casting expression is sufficient and will be much faster as well. Please refer to the Cast category on this site for more information on casting expressions.