Use .NET Built-in Methods to Save Time and Headaches

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

1. str = "something"  
2. if (str == null || str == String.Empty)  
3. {  
4.     // Oh no! the string isn't valid!  
5. }  

 str = "something" if (str == null || str == String.Empty) { 	// Oh no! the string isn't valid! }

Recommended

1. str = "something"  
2. if (String.IsNullOrEmpty(str))  
3. {  
4.     // Oh no! the string isn't valid!  
5. }  

 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

1. str = "something"  
2. if (str == null || str.Trim() == String.Empty)  
3. {  
4.     // Oh no! the string isn't valid!  
5. }  

 str = "something" if (str == null || str.Trim() == String.Empty) { 	// Oh no! the string isn't valid! }

Recommended (C# 4.0 Only)

1. str = "something"  
2. if (String.IsNullOrWhiteSpace(str))  
3. {  
4.     // Oh no! the string isn't valid!  
5. }  

 str = "something" if (String.IsNullOrWhiteSpace(str)) { 	// Oh no! the string isn't valid! }

Code Block #3 – Copy an Array

NOT Recommended

1. string[] source = new string[] { "a", "b", "c" };  
2. string[] dest = new string[3];  
3. for (int i=0; i < source.Length; i++)  
4. {  
5.     dest[i] = source[i];  
6. }  

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

1. string[] source = new string[] { "a", "b", "c" };  
2. string[] dest = new string[3];  
3. Array.Copy(surce, dest, source.Length);  

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

1. char c = '1';  
2. if (c == '1' || c == '2' || c == '3' ||  
3.     c == '4' || c == '5' || c == '6' ||  
4.     c == '7' || c == '8' || c == '9' ||  
5.     c == '0')  
6. {  
7.     // It's a digit!  
8. }  

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

1. char c = '1';  
2. if (Char.IsDigit(c))  
3. {  
4.     // It's a digit!  
5. }  

 char c = '1'; if (Char.IsDigit(c)) { 	// It's a digit! }

Code Block #5 – Combine Paths

NOT Recommended

1. string folder = @"C:\MyDir";  
2. string file = "MyFile.docx";  
3. // Combine to make a path  
4. string path = folder + @"\" + file;  

string folder = @"C:\MyDir"; string file = "MyFile.docx"; // Combine to make a path string path = folder + @"\" + file;

Recommended

1. string folder = @"C:\MyDir";  
2. string file = "MyFile.docx";  
3. // Combine  
4. string path = System.IO.Path.Combine(folder, file);  

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

1. string path = @"C:\MyDir\MyFile.docx";  
2. string extension = path.Substring(path.LastIndexOf("."));  

string path = @"C:\MyDir\MyFile.docx"; string extension = path.Substring(path.LastIndexOf("."));

Recommended

1. string path = @"C:\MyDir\MyFile.docx";  
2. string extension = System.IO.Path.GetExtension(path);  

string path = @"C:\MyDir\MyFile.docx"; string extension = System.IO.Path.GetExtension(path);

Code Block #7 – Get MyDocuments Path

NOT Recommended

1. // Probably some nasty stuff here  

// Probably some nasty stuff here

Recommended

1. Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);  

Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);

Code Block #8 – Check if object is of a specific type

NOT Recommended

1. object obj = "str";  
2. if (obj.GetType() == typeof(String))  
3. {  
4.     // It's a string!  
5. }  

 object obj = "str"; if (obj.GetType() == typeof(String)) { 	// It's a string! }

Recommended

1. object obj = "str";  
2. if (obj is String)  
3. {  
4.     // It's a string!  
5. }  

 object obj = "str"; if (obj is String) { 	// It's a string! }

As Adrian Aisemberg has pointed out, these samples are not entirely the same. The is keyword will return true also if obj is of a derivative type of String (in this sample).

Code Block #9 – Set default enum value

NOT Recommended

1. public class MyClass  
2. {  
3.     private enum Sample   
4.     {  
5.         A,  
6.         B,  
7.         C  
8.     }  
9.     static Sample s = Sample.B; // Set default value explicitly  
10.     public static void Run()  
11.     {     
12.         Console.WriteLine(s); // Prints B  
13.     }  
14. }  

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

1. public class MyClass  
2. {  
3.     private enum Sample   
4.     {  
5.         A,  
6.         B = 0, // Make B the default value  
7.         C  
8.     }  
9.     static Sample s; // Default value will be used  
10.     public static void Run()  
11.     {     
12.         Console.WriteLine(s); // Prints B  
13.     }  
14. }  

 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

1. string str = "Hello World";  
2. if (str.Substring(0, 5) == "Hello")  
3. {  
4.     // String starts with Hello!              
5. }  

 string str = "Hello World"; if (str.Substring(0, 5) == "Hello") { 	// String starts with Hello!			 }

Recommended

1. string str = "Hello World";  
2. if (str.StartsWith("Hello"))  
3. {  
4.     // String starts with Hello!          
5. }  

 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

1. List<int> list = new List<int>(new[] { 1, 2, 3, 4, 5 });  
2. List<string> convertedList = new List<string>();  
3. foreach (int item in list)  
4. {  
5.     convertedList.Add(item.ToString());  
6. }  

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

1. List<int> list = new List<int>(new[] { 1, 2, 3, 4, 5 });  
2. List<string> convertedList = list.ConvertAll<string>(Convert.ToString);  

 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

1. string str = "4";  
2.   
3. int num = 0;  
4. bool success = false;  
5. try   
6. {  
7.     num = Convert.ToInt32(str);  
8.     success = true;  
9. }  
10. catch  
11. {  
12.     success = false;  
13. }  
14.   
15. if (success)  
16. {  
17.     // Do something with the number  
18. }  

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

1. string str = "4";  
2.   
3. int num = 0;  
4. if (Int32.TryParse(str, out num))  
5. {  
6.     // Do something with the number  
7. }  

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

1. const string str = "put me in a file";  
2. const string file = @"c:\logs\file.txt";  
3.   
4. var fs = new FileStream(file, FileMode.Create);            
5. var sw = new StreamWriter(fs);  
6. sw.Write(str);  
7.   
8. sw.Close();  
9. 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

1. const string str = "put me in a file";  
2. const string file = @"c:\logs\file.txt";  
3.   
4. 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

1. string input = "sdfds";  
2. string result = null;  
3. if (input == null)  
4. {  
5.     result = "Input is null!";  
6. }  
7. else  
8. {  
9.     result = input;  
10. }  

string input = "sdfds"; string result = null; if (input == null) { 	result = "Input is null!"; } else { 	result = input; }

Recommended

1. string input = "sdfds";  
2. 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).

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