Learn how to create a comma delimited string that goes past using String.Join method.
Code blocks
Rather than use separate methods, all code is presented in the main method of a Console project.
{
code
}
Where code is isolated from all other code.
Note, index = 1; in this case is out of scope from the assignment.
{
{
int index = 0;
}
index = 1;
}
Convention method to join
Using String.Join to create a comma delimited string of month names which once joined as a string there is no easy method to modify data e.g. add/remove, in this case a month name.
Console.WriteLine(string.Join(",",
DateTimeFormatInfo.CurrentInfo.MonthNames[..^1]));
CommaDelimitedStringCollection
CommaDelimitedStringCollection class provides methods and properties to add, edit, test if values exists, iterate with a for statement and much more.
🛑 Downside and one may guess as the name implies, the delimiter can not be changed from a comma.
Create an instance of CommaDelimitedStringCollection and add month names.
CommaDelimitedStringCollection result = new();
result.AddRange(DateTimeFormatInfo.CurrentInfo.MonthNames[..^1]);
Display the results
Console.WriteLine($"\t{result}");
Remove the current month.
var currentMonthName =
DateTime.Now.ToString("MMMM", CultureInfo.InvariantCulture);
result.Remove(currentMonthName);
Insert the current month back in.
result.Insert(DateTime.Now.Month -1, currentMonthName);
What is cool is iterating the collection, in this case month name.
for (var index = 0; index < result.Count; index++)
{
Console.WriteLine($"{index +1, -3}{result[index]}");
}
Results
1 January
2 February
3 March
4 April
5 May
6 June
7 July
8 August
9 September
10 October
11 November
12 December
Useful for debugging
Example, a developer is testing the following method to find files.
static class FileHelpers
{
/// <summary>
/// Find files with no regard to if the user has permissions
/// </summary>
/// <param name="path">Folder name to check</param>
/// <param name="extensions">file extensions</param>
/// <returns></returns>
public static string[] FilterFiles(string path, params string[] extensions)
=> extensions
.Select(filter => $"*.{filter}")
.SelectMany(item =>
Directory.EnumerateFiles(
path,
item,
SearchOption.AllDirectories)).ToArray();
}
Rather than using StringBuilder the developer can use CommaDelimitedStringCollection.
{
AnsiConsole.MarkupLine("[yellow]Files found[/]");
CommaDelimitedStringCollection result = new();
var files = FileHelpers.FilterFiles(Path.Combine(AppDomain.CurrentDomain.BaseDirectory),"txt","json");
foreach (var file in files)
{
result.Add(Path.GetFileName(file));
}
Console.WriteLine($"\t{result}");
Console.WriteLine(result.Contains("appsettings.json").ToYesNo());
}
Using numerics
As the name implies CommaDelimited*StringCollection* there are no overloads for other types but we can simply do a conversion.
For int array, use the following language extension.
static class Extensions
{
/// <summary>
/// int array to string array
/// </summary>
/// <param name="sender"></param>
public static string[] ToStringArray(this int[] sender)
=> sender.Select(x => x.ToString()).ToArray();
}
Usage
int[] items = { 1, 2, 3 };
CommaDelimitedStringCollection result = new();
result.AddRange(items.ToStringArray());
Check if 3 is in the collection.
result.Contains("3")
Set to read only
For when the collection should not be modified, use SetReadOnly() method.
{
AnsiConsole.MarkupLine("[yellow]Files found[/]");
CommaDelimitedStringCollection result = new();
var files = FileHelpers.FilterFiles(Path.Combine(AppDomain.CurrentDomain.BaseDirectory), "txt", "json");
foreach (var file in files)
{
result.Add(Path.GetFileName(file));
}
Console.WriteLine($"\t{result}");
Console.WriteLine(result.Contains("appsettings.json").ToYesNo());
result.SetReadOnly();
try
{
result.Add("SomeFile.txt");
}
catch (Exception e)
{
Console.WriteLine(e);
}
}
Rather than try/catch
result.SetReadOnly();
if (!result.IsReadOnly)
{
result.Add("SomeFile.txt");
}
Clear the collection
See the Clear method.
Clone the collection
See the Clone method
NuGet packages required
🔸 System.Configuration.ConfigurationManager
Source code
Can be found here which is in a GitHub repository with a mix of other code samples.
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