Can .NET load and parse a properties file equivalent to Java Properties class?

Question

Is there an easy way in C# to read a properties file that has each property on a separate line followed by an equals sign and the value, such as the following:

Answer 1

Final class. Thanks @eXXL.

public class Properties
{
    private Dictionary<String, String> list;
    private String filename;

    public Properties(String file)
    {
        reload(file);
    }

    public String get(String field, String defValue)
    {
        return (get(field) == null) ? (defValue) : (get(field));
    }
    public String get(String field)
    {
        return (list.ContainsKey(field))?(list[field]):(null);
    }

    public void set(String field, Object value)
    {
        if (!list.ContainsKey(field))
            list.Add(field, value.ToString());
        else
            list[field] = value.ToString();
    }

    public void Save()
    {
        Save(this.filename);
    }

    public void Save(String filename)
    {
        this.filename = filename;

        if (!System.IO.File.Exists(filename))
            System.IO.File.Create(filename);

        System.IO.StreamWriter file = new System.IO.StreamWriter(filename);

        foreach(String prop in list.Keys.ToArray())
            if (!String.IsNullOrWhiteSpace(list[prop]))
                file.WriteLine(prop + "=" + list[prop]);

        file.Close();
    }

    public void reload()
    {
        reload(this.filename);
    }

    public void reload(String filename)
    {
        this.filename = filename;
        list = new Dictionary<String, String>();

        if (System.IO.File.Exists(filename))
            loadFromFile(filename);
        else
            System.IO.File.Create(filename);
    }

    private void loadFromFile(String file)
    {
        foreach (String line in System.IO.File.ReadAllLines(file))
        {
            if ((!String.IsNullOrEmpty(line)) &&
                (!line.StartsWith(";")) &&
                (!line.StartsWith("#")) &&
                (!line.StartsWith("'")) &&
                (line.Contains('=')))
            {
                int index = line.IndexOf('=');
                String key = line.Substring(0, index).Trim();
                String value = line.Substring(index + 1).Trim();

                if ((value.StartsWith("\"") && value.EndsWith("\"")) ||
                    (value.StartsWith("'") && value.EndsWith("'")))
                {
                    value = value.Substring(1, value.Length - 2);
                }

                try
                {
                    //ignore dublicates
                    list.Add(key, value);
                }
                catch { }
            }
        }
    }


}

Sample use:

//load
Properties config = new Properties(fileConfig);
//get value whith default value
com_port.Text = config.get("com_port", "1");
//set value
config.set("com_port", com_port.Text);
//save
config.Save()

Answer 2

Most Java ".properties" files can be split by assuming the "=" is the separator - but the format is significantly more complicated than that and allows for embedding spaces, equals, newlines and any Unicode characters in either the property name or value.

I needed to load some Java properties for a C# application so I have implemented JavaProperties.cs to correctly read and write ".properties" formatted files using the same approach as the Java version - you can find it at http://www.kajabity.com/index.php/2009/06/loading-java-properties-files-in-csharp/.

There, you will find a zip file containing the C# source for the class and some sample properties files I tested it with.

Enjoy!

Answer 3

No there is no built-in support for this.

You have to make your own "INIFileReader". Maybe something like this?

var data = new Dictionary<string, string>();
foreach (var row in File.ReadAllLines(PATH_TO_FILE))
  data.Add(row.Split('=')[0], string.Join("=",row.Split('=').Skip(1).ToArray()));

Console.WriteLine(data["ServerName"]);

Edit: Updated to reflect Paul's comment.

Answer 4

There are several NuGet packages for this, but all are currently in pre-release version.

• Capgemini.Cauldron.Core.JavaProperties 2.0.39-beta
• Kajabity.Tools.Java 0.2.6638.28124

[Update] As of June 2018, Capgemini.Cauldron.Core.JavaProperties is now in a stable version (version 2.1.0 and 3.0.20).

Answer 5

I realize that this isn't exactly what you're asking, but just in case:

When you want to load an actual Java properties file, you'll need to accomodate its encoding. The Java docs indicate that the encoding is ISO 8859-1, which contains some escape sequences that you might not correctly interpret. For instance look at this SO answer to see what's necessary to turn UTF-8 into ISO 8859-1 (and vice versa)

When we needed to do this, we found an open-source PropertyFile.cs and made a few changes to support the escape sequences. This class is a good one for read/write scenarios. You'll need the supporting PropertyFileIterator.cs class as well.

Even if you're not loading true Java properties, make sure that your prop file can express all the characters you need to save (UTF-8 at least)

Answer 6

I don't know of any built-in way to do this. However, it would seem easy enough to do, since the only delimiters you have to worry about are the newline character and the equals sign.

It would be very easy to write a routine that will return a NameValueCollection, or an IDictionary given the contents of the file.