从App.config文件中读取集合

Question

I'm trying to get a collection of Items from the configuration file of an application. Everything looks ok, but I always fetch 0 elements (regardless that I put on the configuration file...)

My code is:

using System.Configuration;

namespace CustomSettingConfiguration
{
    public class TestConfigurationElement : ConfigurationElement
    {
        [ConfigurationProperty("name", IsKey = true, IsRequired = true)]
        public string Name
        {
            get { return (string) this["name"]; }
        }
    }

[ConfigurationCollection(typeof (TestConfigurationElement), AddItemName = "test")]
public class TestConfigurationElementCollection : ConfigurationElementCollection
{
    protected override ConfigurationElement CreateNewElement()
    {
        return new TestConfigurationElement();
    }

    protected override object GetElementKey(ConfigurationElement element)
    {
        return ((TestConfigurationElement) element).Name;
    }
}

public class TestConfigurationSection : ConfigurationSection
{
    [ConfigurationProperty("Tests", IsDefaultCollection = true)]
    public TestConfigurationElementCollection Tests
    {
        get { return (TestConfigurationElementCollection)this["Tests"]; }
    }
}
}

And the configuration file:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
   <configSections>
    <section name="TestConfigurationSection" type="CustomSettingConfiguration.TestConfigurationSection" />
  </configSections>

  <TestConfigurationSection>
    <Tests>
      <test name="One" />
      <test name="Two" />
    </Tests>
  </TestConfigurationSection>

</configuration>

To use It:

  TestConfigurationSection a = new TestConfigurationSection();
  var tests = a.Tests;

Any idea??

Thanks in advance

Answer 1

You should another code to load configuration settings:

TestConfigurationSection a = (TestConfigurationSection) System.Configuration.ConfigurationManager.GetSection("TestConfigurationSection");

also make sure that assemply is specified in your configuration file:

<section name="TestConfigurationSection" type="CustomSettingConfiguration.TestConfigurationSection, ConsoleApplication1" />

Answer 2

Does it really need it's own configuration section? Personally, I seldom find it necessary to go beyond the simple settings in the project properties. Here's how I did it in a project where I wanted to use a list of sources that were allowed and disallowed. The object I wanted to save in configuration (in my case, user.config, but the principle is the same for app.config) is a plain c# object (it implements an interface that isn't germane to this discussion is all).

So to make it easy, I created a collection class for my object. This simplifies the setting-up part. Here's the class, in its entirety:

// This is mainly declared to ease use as a User Setting
public class SpellSourceCollection : List<SpellSource>
{
    public SpellSourceCollection() : base() { }
    public SpellSourceCollection(IEnumerable<SpellSource> ListToCopy)
        : this()
    {
        this.AddRange(ListToCopy);
    }
}

Remember that "SpellSource" has nothing special about it. Now, in the settings for the project, I can assign the Type as my collection object.

You may have to "Browse" to the correct custom object. Once it's done, however, reading from app.config (or user.config) is a breeze. Here's what the config file looks like (slightly abbreviated).

<setting name="Sources" serializeAs="Xml">
    <value>
        <ArrayOfSpellSource xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
            <SpellSource>
                <Source>PFRPG Advanced Player's Guide</Source>
                <Allowed>true</Allowed>
                <BackgroundColor>White</BackgroundColor>
            </SpellSource>
            <SpellSource>
                <Source>PFRPG Core</Source>
                <Allowed>true</Allowed>
                <BackgroundColor>White</BackgroundColor>
            </SpellSource>
            <SpellSource>
                <Source>Rival Guide</Source>
                <Allowed>false</Allowed>
                <BackgroundColor>White</BackgroundColor>
            </SpellSource>
            <SpellSource>
                <Source>Ultimate Combat</Source>
                <Allowed>true</Allowed>
                <BackgroundColor>White</BackgroundColor>
            </SpellSource>
            <SpellSource>
                <Source>Ultimate Magic</Source>
                <Allowed>true</Allowed>
                <BackgroundColor>Cyan</BackgroundColor>
            </SpellSource>
        </ArrayOfSpellSource>
    </value>
</setting>

Getting at the property is simply a matter of

SpellSourceCollection settingsSources = Properties.Settings.Default.Sources;
// do stuff or even later in your project, you can save this user setting
Properties.Settings.Default.Sources = settingsSources;
Properties.Settings.Default.Save();

You can apply that to your own project in similar fashion. The only mildly tricky bits are declaring the collection object and creating the setting in the project properties.