You can easily add new properties using the new property editor, the framework handles the rest.
The properties you can buy, show up as green dollar signs on the map. (Purchased properties show up as red dollar signs.)
To purchase a property, go there, and hold the action key on the big green marker. (Text should show up listing the price, etc,. It may take a second to show up when entering a marker, and to vanish when leaving a marker.)
You will collect rent on an hourly basic from purchased properties. (Adjust the rent value for each property in the .xml file to suite your taste.)
The property editor is a new feature, which gives you an in-game GUI for adding properties.
To access the property editor, you will need to press the tilde key(~, `), this will open a console, type the command "PropertyEditor" and press 'Enter' to open the editor. (Press the tilde key again, to close the console, and use the property editor.)
The editor is straightforward, enter a name, a price, and a value for rent, and click the submit button. (It shows examples of what values it expects, and has basic error checking in place just in case.)
The map icon\marker for your newly created property will be placed wherever you are standing when you click submit, so, position yourself appropriately before opening the editor.
You can manually edit existing entries, or add new ones to the file "Properties.xml". (Editing is trivial, I'm sure you can figure it out.)
Adding a new property, is as simple as filling out the information above, and copying it into the file "Properties.xml". (Pay attention to the files layout, and match it.)
You can remove entries as well, just remove the entire entry, as shown above.
Note: The XML is only read once during the initial loading of the script, so, changes made during the game won't take effect, unless you use the console, and the "ReloadScripts" command. (I suggest sticking to the property editor, if you don't know what you're doing.)
GTAIV .Net Script Hook v188.8.131.52 BETA
The .Net Script Hook has it's own requirements, be sure to read them, and get anything you need. (See link.)
Place the files "RealEstate.net" and "Properties.xml" into your GTAIV directory, in a subfolder called "scripts". (This is where the .exe for the game is located, etc,. You may need to create the "scripts" subfolder.)
(The same applies to EFLC\DLC\Total Conversions\Etc, but, not all properties will be correct using those, a custom "Properties.xml" needs to be created for each one.)
1. Purchased properties map icon now turns red, making it easier to distinguish between owned properties, and ones you don't own.
2. I've enabled a feature that makes map icons only show up when you get near them. (This only effects the mini-map, it basically keeps the mini-map from getting too crowded.)
3. Property Editor added.
1. Fixed button alignment issues with the "Property Editor".
2. Made the console close itself after opening the "Property Editor".
Download v1.1a (Source code included.)
Feel free to re-host this, edit it, use portions of the code, etc,.
Basically, do anything you want with it, just give me credit for my work.