Int to Hex in C#

Methods to Convert Int to Hex in C#: Step-by-Step Reference with Example Snippets

There are several fast and efficient ways to convert a value into a hexadecimal text output in C#. Each approach serves unique scenarios, from quick display with ToString("X") to deeper manipulation with BitConverter.ToString or the latest .NET ToHexString() overloads. Below, you'll find clear illustrations, pros/cons, and a comparison of output structure. The fastest way to check what color a UIColor float value actually renders is to run it through the uicolor to hex converter.

Hex Conversion with ToString("X"): The Most Direct Approach

Using int.ToString("X") provides a text result with hex characters in uppercase (e.g., 16.ToString("X") returns 10).

// Basic usage
int value = 255;
string hex = value.ToString("X"); // Output: "FF"

• Add zeros to the left for consistent width: value.ToString("X4") returns 00FF.
• For lowercase, apply ToLower() on the result: value.ToString("X").ToLower() yields ff.

Worked Example: Basic Value to Base16 Representation

1. Identify the value: int number = 47;
2. Format as hex: string hx = number.ToString("X");
3. Result: "2F" (uppercase, as per C# default).

Convert with Convert.ToString(): For Flexible Numeric Types

The Convert.ToString(int, 16) approach generates a lowercase hexadecimal outcome.

// Usage
int x = 255;
string hexLower = Convert.ToString(x, 16); // Output: "ff"
string hexUpper = Convert.ToString(x, 16).ToUpper(); // "FF"

• Works with int32, unsigned numbers, and other numeric kinds.
• No built-in padding—add manual zeros at the start for fixed width:

string formatted = Convert.ToString(x, 16).PadLeft(4, '0'); // "00ff"

Tip: This technique is platform-independent and keeps your output readable across different environments.

Using Byte Arrays: BitConverter.ToString and ToHexString()

If you want to change bytes from a byte array—for example, when reading binary files or network packets—C# offers the comprehensive BitConverter.ToString and the modern Convert.ToHexString methods for .NET 5+. These handle overloads for byte[], int32, int32, and ReadOnlySpan<byte>, allowing for targeted handling of array segments and efficient memory use. For those using the C# programming guide on Microsoft Docs, these APIs are featured prominently.

// Example using BitConverter.ToString
byte[] arr = new byte[] { 18, 44, 189 };
string hxVal = BitConverter.ToString(arr); // Output: "12-2C-BD"
// Remove dashes for pure base-16 output:
string noDashes = hxVal.Replace("-", ""); // "122CBD"

// Example using Convert.ToHexString (NET 5.0+)
byte[] arr2 = { 255, 0, 127 };
string hex2 = Convert.ToHexString(arr2); // Output: "FF007F"

Worked Example: Byte Array to Hex String

1. Start with a byte array: byte[] bytes = Encoding.ASCII.GetBytes("Hi!");
2. Change with Convert.ToHexString: string result = Convert.ToHexString(bytes);
3. Result: 486921 (for "Hi!").

Method Overloads for ToHexString and BitConverter

Example: Formatting Hex Output with Zeros Added

1. Input: int value = 7;
2. Format as 4-digit base16: string hx = value.ToString("X4");
3. Result: "0007"

Example: Converting Integer to Hex Color Code

1. Suppose you have RGB amounts: int r = 255, g = 99, b = 71;
2. Combine and format as hex color: string colorHex = $"#{r:X2}{g:X2}{b:X2}";
3. Result: "#FF6347"