Question

I have a ‘settings file’ in my Winforms application called Settings.settings with a partial class for custom methods, etc. Is there a way to load / save dynamic settings based on arbitrary keys?

For example, I have some ListViews in my application in which I want to save / load the column widths; Instead of creating a width setting for each column for each list view I would like a simple method to load / save the widths automatically.

Below is an example of the save method I have tried:

internal sealed partial class Settings {     public void SetListViewColumnWidths(ListView listView)     {         String baseKey = listView.Name;         foreach (ColumnHeader h in listView.Columns)         {             String key = String.Format('{0}-{1}', baseKey, h.Index);             this[key] = h.Width;         }     } } 

When running that code I get the error ‘The settings property ‘TestsListView-0′ was not found.’ Is there something I am missing?

Answer 1

Store your column width settings in an Xml Serializable object. Ie, something that implements IXmlSerializable then create a single setting entry of that type in Settings.settings.

A good option would probably be an Xml Serializable Dictionary. A quick google search found quite a few different blog posts that describe how to implement that.

As mentioned in other answers you’ll need to ensure that this object is a User setting. You may also need to initialize the setting instance. Ie, create a XmlSerializableDictionary() instance and assign it to the setting if the setting is null. The settings subsystem doesn’t create default instances of complex setting objects.

Also, if you want these settings to persist between assembly versions (ie, be upgradable) you will need to upgrade the settings on application startup. This is described in detail on Miha Markič’s blog and Raghavendra Prabhu’s blog.