During our everyday programming tasks we run into several repetitive code blocks that after the 20th time you implement them become really annoying. The worst case is to re-implement these code blocks every time, and the better case is to create a central class library with helper classes and methods. However, a large amount of these tasks can be achieved easily with built-in .NET methods.
In this post I will go through several repetitive code blocks and show you how to implement them using built-in .NET method. If you want to add your suggestions, comment! I’ll add your suggestions to the post periodically.
Disclaimer: I’m sure some of the code blocks I use in the NOT Recommended sections can be written much better. These code blocks are here just for demonstration purposes.
Code Block #1 – Check string for nullity or emptiness
NOT Recommended
str = "something"
if (str == null || str == String.Empty)
{
// Oh no! the string isn't valid!
}Recommended
str = "something"
if (String.IsNullOrEmpty(str))
{
// Oh no! the string isn't valid!
}Code Block #2 – Check string for nullity or emptiness (spaces only string is invalid too)
NOT Recommended
str = "something"
if (str == null || str.Trim() == String.Empty)
{
// Oh no! the string isn't valid!
}Recommended (C# 4.0 Only)
str = "something"
if (String.IsNullOrWhiteSpace(str))
{
// Oh no! the string isn't valid!
}Code Block #3 – Copy an Array
NOT Recommended
string[] source = new string[] { "a", "b", "c" };
string[] dest = new string[3];
for (int i=0; i < source.Length; i++)
{
dest[i] = source[i];
}Recommended
string[] source = new string[] { "a", "b", "c" };
string[] dest = new string[3];
Array.Copy(surce, dest, source.Length);Code Block #4 – Check if a char is a digit
NOT Recommended
char c = '1';
if (c == '1' || c == '2' || c == '3' ||
c == '4' || c == '5' || c == '6' ||
c == '7' || c == '8' || c == '9' ||
c == '0')
{
// It's a digit!
}Recommended
char c = '1';
if (Char.IsDigit(c))
{
// It's a digit!
}Code Block #5 – Combine Paths
NOT Recommended
string folder = @"C:\MyDir";
string file = "MyFile.docx";
// Combine to make a path
string path = folder + @"\" + file;
Recommended
string folder = @"C:\MyDir";
string file = "MyFile.docx";
// Combine
string path = System.IO.Path.Combine(folder, file);
Code Block #6 – Get file extension out of a file path
NOT Recommended
string path = @"C:\MyDir\MyFile.docx";
string extension = path.Substring(path.LastIndexOf("."));Recommended
string path = @"C:\MyDir\MyFile.docx";
string extension = System.IO.Path.GetExtension(path);
Code Block #7 – Get MyDocuments Path
NOT Recommended
// Probably some nasty stuff here
Recommended
Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
Code Block #8 – Check if object is of a specific type
NOT Recommended
object obj = "str";
if (obj.GetType() == typeof(String))
{
// It's a string!
}Recommended
object obj = "str";
if (obj is String)
{
// It's a string!
}Code Block #9 – Set default enum value
NOT Recommended
public class MyClass
{
private enum Sample
{
A,
B,
C
}
static Sample s = Sample.B; // Set default value explicitly
public static void Run()
{
Console.WriteLine(s); // Prints B
}
}Recommended
public class MyClass
{
private enum Sample
{
A,
B = 0, // Make B the default value
C
}
static Sample s; // Default value will be used
public static void Run()
{
Console.WriteLine(s); // Prints B
}
}Code Block #10 – Check if a string starts with another string
NOT Recommended
string str = "Hello World";
if (str.Substring(0, 5) == "Hello")
{
// String starts with Hello!
}Recommended
string str = "Hello World";
if (str.StartsWith("Hello"))
{
// String starts with Hello!
}Code Block #11 – Convert list of items of one type to a list of items of a different type
NOT Recommended
List<int> list = new List<int>(new[] { 1, 2, 3, 4, 5 });
List<string> convertedList = new List<string>();
foreach (int item in list)
{
convertedList.Add(item.ToString());
}Recommended
List<int> list = new List<int>(new[] { 1, 2, 3, 4, 5 });
List<string> convertedList = list.ConvertAll<string>(Convert.ToString);Code Block #12 – Check if a string contains a number and get the number
NOT Recommended
string str = "4";
int num = 0;
bool success = false;
try
{
num = Convert.ToInt32(str);
success = true;
}
catch
{
success = false;
}
if (success)
{
// Do something with the number
}Recommended
string str = "4";
int num = 0;
if (Int32.TryParse(str, out num))
{
// Do something with the number
}Code Block #13 – Writing a string to a file (courtesy of Yaron Naveh)
NOT Recommended
- const string str = "put me in a file";
- const string file = @"c:\logs\file.txt";
-
- var fs = new FileStream(file, FileMode.Create);
- var sw = new StreamWriter(fs);
- sw.Write(str);
-
- sw.Close();
- fs.Close();
const string str = "put me in a file";
const string file = @"c:\logs\file.txt";
var fs = new FileStream(file, FileMode.Create);
var sw = new StreamWriter(fs);
sw.Write(str);
sw.Close();
fs.Close();
Recommended
- const string str = "put me in a file";
- const string file = @"c:\logs\file.txt";
-
- File.WriteAllText(file, str);
const string str = "put me in a file";
const string file = @"c:\logs\file.txt";
File.WriteAllText(file, str);
Code Block #14 – Pick value if not null and a different on if it is (courtesy of Abhishek)
NOT Recommended
- string input = "sdfds";
- string result = null;
- if (input == null)
- {
- result = "Input is null!";
- }
- else
- {
- result = input;
- }
string input = "sdfds";
string result = null;
if (input == null)
{
result = "Input is null!";
}
else
{
result = input;
}
Recommended
- string input = "sdfds";
- string result = input ?? "Input is null!";
string input = "sdfds";
string result = input ?? "Input is null!";
This is it for now. If you have more, comment and I’ll add your suggestions to the list (with credits).
All the best,
Shay.