Most useful .NET utility classes developers tend to reinvent rather than reuse

Question

I recently read this Phil Haack post (The Most Useful .NET Utility Classes Developers Tend To Reinvent Rather Than Reuse) from last year, and thought I'd see if anyone has any additions to the list.

Answer 1

Enum.Parse()

Answer 2

String.Format.

The number of times I've seen

return "£" & iSomeValue

rather than

return String.Format ("{0:c}", iSomeValue)

or people appending percent signs - things like that.

Answer 3

String.IsNullOrEmpty()

Answer 4

String.Join() (however, almost everyone knows about string.Split and seems to use it every chance they get...)

Answer 5

System.Text.RegularExpressions.Regex

Answer 6

Many people seem to like stepping through an XML file manually to find something rather than use XPathNaviagator.

Answer 7

input.StartsWith("stuff") instead of Regex.IsMatch(input, @"^stuff")

Answer 8

Path.GetFileNameWithoutExtension(string path)

Returns the file name of the specified path string without the extension.

Path.GetTempFileName()

Creates a uniquely named, zero-byte temporary file on disk and returns the full path of that file.

Answer 9

Hard coding a / into a directory manipulation string versus using:

IO.Path.DirectorySeparatorChar

Answer 10

File stuff.

using System.IO;

File.Exists(FileNamePath)

Directory.Exists(strDirPath)

File.Move(currentLocation, newLocation);

File.Delete(fileToDelete);

Directory.CreateDirectory(directory)

System.IO.FileStream file = System.IO.File.Create(fullFilePath);

Answer 11

System.IO.File.ReadAllText vs writing logic using a StreamReader for small files.

System.IO.File.WriteAllText vs writing logic using a StreamWriter for small files.

Answer 12

People tend to use the following which is ugly and bound to fail:

string path = basePath + "\\" + fileName;

Better and safer way:

string path = Path.Combine(basePath, fileName);

Also I've seen people writing custom method to read all bytes from file. This one comes quite handy:

byte[] fileData = File.ReadAllBytes(path); // use path from Path.Combine

As TheXenocide pointed out, same applies for File.ReadAllText() and File.ReadAllLines()

Answer 13

Path.Append is always forgotten in stuff I have seen.

Answer 14

The StringBuilder class and especially the Method AppendFormat.

P.S.: If you are looking for String Operations performance measurement: StringBuilder vs. String / Fast String Operations with .NET 2.0

Answer 15

See Hidden .NET Base Class Library Classes

Answer 16

Trying to figure out where My Documents lives on a user's computer. Just use the following:

string directory =
Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);

Answer 17

The System.Diagnostics.Stopwatch class.

Answer 18

Most people forget that Directory.CreateDirectory() degrades gracefully if the folder already exists, and wrap it with a pointless, if (!Directory.Exists(....)) call.

Answer 19

Environment.NewLine

Answer 20

I needed to download some files recently in a windows application. I found the DownloadFile method on the WebClient object:

    WebClient wc = new WebClient();
    wc.DownloadFile(sourceURLAddress, destFileName);

Answer 21

Instead of generating a file name with a Guid, just use:

Path.GetRandomFileName()

Answer 22

• Using DebuggerDisplay attribute instead of ToString() to simplify the debugging.
• Enumerable.Range
• Tuples from FSharp.Core!

Answer 23

myString.Equals(anotherString)

and options including culture-specific ones.

I bet that at least 50% of developers write something like: if (s == "id") {...}

Answer 24

Lots of the new Linq features seem pretty unknown:

Any<T>() & All<T>()

if( myCollection.Any( x => x.IsSomething ) )
    //...

bool allValid = myCollection.All( 
    x => x.IsValid );

ToList<T>(), ToArray<T>(), ToDictionary<T>()

var newDict = myCollection.ToDictionary(
    x => x.Name,
    x => x.Value );

First<T>(), FirstOrDefault<T>()

return dbAccessor.GetFromTable( id ).
    FirstOrDefault();

Where<T>()

//instead of
foreach( Type item in myCollection )
    if( item.IsValid )
         //do stuff

//you can also do
foreach( var item in myCollection.Where( x => x.IsValid ) )
    //do stuff

//note only a simple sample - the logic could be a lot more complex

All really useful little functions that you can use outside of the Linq syntax.

Answer 25

For all it's hidden away under the Microsoft.VisualBasic namespace, TextFieldParser is actually a very nice csv parser. I see a lot of people either roll their own (badly) or use something like the nice Fast CSV library on Code Plex, not even knowing this is already baked into the framework.