Parsing a value from string to an unknown variable type

Question

For a game I'm developing on (in C#), we need to be able to save and load options files, and for ease of use, we decided to do it as plain text. I have a problem however when I try to load the text back into their variables as I don't always know what type of variable it needs to be loaded into.

The following line of code works, except for the fact that I have yet to find functionallity that resembles

f.GetType().Parse()

Heres the actual code

OptionsClass current = new OptionsClass();  
    using(StreamReader reader = new StreamReader(path)){
        string line;
        while((line = reader.ReadLine()) != null){
        foreach(FieldInfo f in typeof(OptionsClass).GetFields()){
            f.SetValue(current, f.GetType().Parse(line.Split(new char[] {'='})[1]));

        }
    }
}

Let me know if anything is unclear, or more information is needed. Regards, -Logan

What you're trying to do is known as serialization. If you search for ".net serialization", there is a wealth of info on how to persist and restore information automatically based on the structure/contents of a class. — Dan Bryant
– Dan Bryant, Commented Nov 30, 2011 at 23:51
If you use something like SOAP, it serializes all the datatypes along with the values. It's designed for doing exactly this. — Mike Christensen
– Mike Christensen, Commented Nov 30, 2011 at 23:56

competent_tech · Accepted Answer · 2011-11-30 23:58:11Z

6

Rather than trying to do this yourself, I would suggest that you use the builtin XML or JSON serialiation.

However, if you are going to implement this yourself, then I would suggest that you perform a switch on the type of field and convert the value according to the data type of the field. For example:

        string sValue = line.Split(new char[] {'='})[1]);
        object oValue;
        switch (f.FieldType.Name.ToLower())
        {
            case "system.string":
               oValue = sValue;
               break;

            case "system.int32":
                oValue = Convert.ToInt32(sValue);
                break;
         etc...

      f.SetValue(current, oValue);

One additional note: if you are going the self-built route, then you probably want to be a little more robust in the data conversions (i.e. checking to see if the string is not null and is numeric when converting to a number, etc).

edited Nov 30, 2011 at 23:58

answered Nov 30, 2011 at 23:52

competent_tech

45.1k12 gold badges96 silver badges114 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

dash · Accepted Answer · 2011-12-01 00:00:05Z

4

I'd definitely add that this is a perfect case for serialization.

However, if you want, you can also use:

Convert.ChangeType(object value, Type type)

So in the example above it would be something like:

f.SetValue(current, Convert.ChangeType(f.GetType().Parse(line.Split(new char[] {'='})[1])), f.GetType());

Note this doesn't check for null values.

answered Dec 1, 2011 at 0:00

dash

91.8k4 gold badges55 silver badges72 bronze badges

Comments

Kristopher · Accepted Answer · 2013-05-20 18:44:43Z

3

Are you looking for something like this? Assuming you know what order your objects are coming in:

var converter = TypeDescriptor.GetConverter(f.GetType());
var result = converter.ConvertFrom(line.Split(new char[] {'='})[1]));

answered May 20, 2013 at 18:44

Kristopher

87815 silver badges32 bronze badges

Comments

corsiKa · Accepted Answer · 2011-11-30 23:53:21Z

0

If you wrote it out, you should know what order you wrote it out in, and read it in the same order.

answered Nov 30, 2011 at 23:53

corsiKa

82.8k26 gold badges162 silver badges210 bronze badges

1 Comment

Logan Over a year ago

True, it's just that my options class contains quite a few variables, and as we are still developing i may add more later, so i just want to limit the amount of places i have to make changes when/if i do make changes.

Keith Nicholas · Accepted Answer · 2011-11-30 23:55:17Z

0

go to your Project Properties -> Settings -> Create the settings you want,

then to get at them

var x = Properties.Settings.Default.MyCoolSetting;

(you can read and write them)

these settings will be stored in your applications .config file under user settings, where you can edit them

answered Nov 30, 2011 at 23:55

Keith Nicholas

44.5k15 gold badges101 silver badges168 bronze badges

Collectives™ on Stack Overflow

Parsing a value from string to an unknown variable type

5 Answers 5

Comments

Comments

Comments

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

Comments

Comments

Comments

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related