Hack Forums
[C#] [C#][TUT]How to use Dictionaries! - Printable Version

+- Hack Forums (https://hackforums.net)
+-- Forum: Tech (https://hackforums.net/forumdisplay.php?fid=444)
+--- Forum: Coding (https://hackforums.net/forumdisplay.php?fid=151)
+---- Forum: Software Development (https://hackforums.net/forumdisplay.php?fid=118)
+---- Thread: [C#] [C#][TUT]How to use Dictionaries! (/showthread.php?tid=943217)

[C#][TUT]How to use Dictionaries! - Ethereal - Jan 1, 2011

A dictionary is basically a database that you can easily access within your code. It has two variables - The key, and the value. You can access the value via a lookup utilizing the key. The following code is the syntax for declaring a new dictionary:

Code
Dictionary<varType1,varType2> DicName = new Dictionary<varType1,varType2>();

For example:

Code
private Dictionary<String, String> _keySettings = new Dictionary<String,String>();

NOTE* It uses the class, rather than the type.

We can add values to our dictionary very easily:

Code
DicName.Add(var1, var2)

For example:

Code
_keySettings.Add(kname, kval);

This will be our first entry in our Dictionary. We can check how many values we have in our Dictionary with the code:

Code
DicName.Count();

When we wish to access the data contained inside our Dictionary, we can call a lookup with the key as a parameter. This will return the value that the key corresponds to:

Code
DicName[key];

And an example for outputting the values stored in the Dictionary into a listbox is:

Code
foreach(string s in GetDictionaryKeys()) {
listBox1.Items.Add(s); }

public string[] GetDictionaryKeys() { return _keySettings.Values.ToArray(); }

Now we are past the boring bit. You may ask where you would use this over an array, or other variable type? I personally first used this to hold the variable data for a program that allows you to manipulate a CS:S config.

I read text from a file, parsed it and then added it into a Dictionary. The Dictionary data can then be passed to another form, for you to access as you please.

Then, in a second form, I allowed new values to be entered changing the keybinding, and re-wrote the dictionary. Lookups were then used to re-write the config, with the new configuration settings.

I have also used this as a lookup to convert characters/numeric values for my private encryption methods.

This is just one example of implementing a Dictionary. Your use of it is limited only by your imagination.