programatically save a ConfigurationElementCollection with attributes

  • Thread starter Thread starter Eric
  • Start date Start date
E

Eric

Hi Folks,

I wrote a custom configuration element which is
ConfigurationElementCollection with attributes. The configuration
section does look like this:

<rules name="Personal Rules">
<rule name="Rule 01" order="1" />
<rule name="Rule 02" order="2" />
</rules>

I read the attributes overriding the
OnDeserializeUnrecognizedAttribute method with no problem, but I can't
find a methos to actually Serialize the collection attribute, which
limits the way I can programmatically update the configuration.

Does anyone how can I do programmatically save this attribute?

Thanks in advance.
 
Hi,

You might want to use the built in configuration support for this.
Example :
namespace RuleConfig
{
public class RuleElement : ConfigurationElement
{
private static readonly ConfigurationProperty _order;
private static readonly ConfigurationProperty _name;
private static readonly ConfigurationPropertyCollection _properties;
static RuleElement()
{
_order = new ConfigurationProperty("order", typeof(int), null,
ConfigurationPropertyOptions.IsRequired);
_name = new ConfigurationProperty("name", typeof(string), null,
ConfigurationPropertyOptions.IsRequired);
_properties = new ConfigurationPropertyCollection();
_properties.Add(_order);
_properties.Add(_name);
}
public string Name
{
get { return (string)base[_name]; }
set { base[_name] = value; }
}
public int Order
{
get { return (int)base[_order]; }
set { base[_order] = value; }
}
protected override ConfigurationPropertyCollection Properties
{
get
{
return _properties;
}
}
}
[ConfigurationCollection(typeof(RuleElement), CollectionType =
ConfigurationElementCollectionType.BasicMap, AddItemName = "rule")]
public class RuleCollection : ConfigurationElementCollection
{
public void Add(RuleElement element)
{
base.BaseAdd(element);
}
protected override ConfigurationElement CreateNewElement()
{
return new RuleElement();
}
protected override object GetElementKey(ConfigurationElement
element)
{
return ((RuleElement)element).Order;
}
protected override string ElementName
{ get { return "rule"; } }
public override ConfigurationElementCollectionType CollectionType
{ get { return ConfigurationElementCollectionType.BasicMap; } }
}
public class RuleSection : ConfigurationSection
{
private static readonly ConfigurationProperty _rules;
private static readonly ConfigurationPropertyCollection _properties;
static RuleSection()
{
_rules = new ConfigurationProperty(null, typeof(RuleCollection),
null, ConfigurationPropertyOptions.IsDefaultCollection);
_properties = new ConfigurationPropertyCollection();
_properties.Add(_rules);
}
protected override ConfigurationPropertyCollection Properties
{
get
{
return _properties;
}
}
public RuleCollection Rules
{
get { return (RuleCollection)base[_rules]; }
}
}
}
-----------------------------------Example app.config
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<configSections>
<section type="RuleConfig.RuleSection, RuleConfig" name="rules"/>
</configSections>
<rules>
<rule order="1" name="name1"/>
<rule order="2" name="name2"/>
</rules>
</configuration>
----------------------------------Example of use
Configuration config =
ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
RuleSection section = config.GetSection("rules") as RuleSection;
if (section != null)
{
//read
foreach (RuleElement rule in section.Rules)
System.Console.WriteLine(string.Format("{0,5}:{1}", rule.Order,
rule.Name));
//modify
section.Rules.Add(new RuleElement() { Order = 8, Name = "name8" });
config.Save(ConfigurationSaveMode.Modified);
}


Hope You find this useful.
-Zsolt
 
    public class RuleElement : ConfigurationElement
    {
        private static readonly ConfigurationProperty _order;
        private static readonly ConfigurationProperty _name;
        private static readonly ConfigurationPropertyCollection _properties;
-Zsolt
Click to expand...

Nice!! thanks Miher. I was declaring the property trought the use of
ConfigurationProperty attribute but I did'nt realize that in the case
of a collection, I still have to create the ConfigurationProperty by
hand.

One final question, I saw examples of custom configuration where the
property is a static variable, just like yours, and other where they
are instance fields. Is it safe to declare them as static?

tahnks a lot.
 
Hi,
Nice!! thanks Miher. I was declaring the property trought the use of
ConfigurationProperty attribute but I did'nt realize that in the case
of a collection, I still have to create the ConfigurationProperty by
hand.
Click to expand...
You can do it with attributes also, instead of declaring the
ConfigurationProperties, the two are the same.
One final question, I saw examples of custom configuration where the
property is a static variable, just like yours, and other where they
are instance fields. Is it safe to declare them as static?
Click to expand...
These fields only describe the properties so i dont see anything against
declaring those as static variables (and with that we also prevent them
being cloned to every instance.)

It just came to my mind that i have read a really cool article about this,
You might want to check it out. :
http://www.codeproject.com/KB/dotnet/mysteriesofconfiguration.aspx

Hope You find this useful.
-Zsolt
 
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