Analyzing Risk

Just read a great article about risk on MSDN. While evaluating risks in my daily job, it puts some things in context (like the top 10 project risks) .

Creating a configuration section

In general, a lot of application are using the appSettings section of a config file for storing application parameters. A major drawback of this practice, is the lack of prior knowledge about the format and default value of these parameters, so you need to program all this functionality yourself.
A better way to provide your application with configuration values, is the use of a configuration section. Instead of using the appSettings node, you can specify your own.
The key to your own configuration section is the System.Configuration namespace.
You write your own class, but should inherit ConfigurationSection.
Now you can spice up your properties in this class with the ConfigurationProperty attribute. Validation can be programmed with the attributes

• IntegerValidatorAttribute
• LongValidatorAttribute
• RegexStringValidatorAttribute
• StringValidatorAttribute
• TimeSpanValidatorAttribute

For example:

public class TestConfigurationSection : ConfigurationSection
{
// Empty Construct
public TestConfigurationSection() { }

// default string property
[ConfigurationProperty("deliveryStore", IsRequired = true)]
public string DeliveryStore
{
get
{
return (string)this["deliveryStore"];
}
set
{
this["deliveryStore"] = value;
}
}
//uri types will work too
[ConfigurationProperty("serviceUrl", DefaultValue = "http://192.168.1.10/MessageService", IsRequired = false)]
public Uri ServiceUrl
{
get
{
return (Uri)this["serviceUrl"];
}
set
{
this["serviceUrl"] = value;
}
}

[ConfigurationProperty("timeOut", DefaultValue = "0:00:20")]
[TimeSpanValidator(MinValueString = "0:00:05", MaxValueString = "0:05:00", ExcludeRange = false)]
public TimeSpan TimeOut
{
get
{
return (TimeSpan)this["timeOut"];
}
set
{
this["timeOut"] = value;
}
}
}


To use this configuration section in your config, you need to add it to the configsections node, for instance:

<configSections>
<section name="testConfig" type="NJV.Utils.TestConfigurationSection, NJV.Utils"/>
</configSections>
<testConfig
deliveryStore="D:\Test"
serviceUrl="http://10.0.0.9/MessageService"
timeOut="0:00:20"
/>


Now you've the settings defined and validation setup. To read these values, you can use the following code:

TestConfigSection config = (TestConfigSection)System.Configuration.ConfigurationManager.GetSection("testConfig");
TimeSpan timeout = config.TimeOut;
string deliveryLocation = config.DeliveryStore;
Uri serviceLocation = config.ServiceUrl;


The only drawback here is, you should be sure to have a testConfig section defined in your config, and it should be of the correct type. So maybe there could be some type and null reference checking on line 1:

TestConfigSection config = System.Configuration.ConfigurationManager.GetSection("testConfig") as TestConfigSection;
if (config==null)
{
throw new ApplicationException("No configuration available");
}


Certified SQL Server Developer

With the wave of beta exams the last month, I've earned three new certifications:
MCTS: SQL Server 2008, Database Development, MCTS: SQL Server 2008, Business Intelligence Development and Maintenance and MCITP: Database Developer 2008.

Quite funny the SQL Developer is under the MCITP certification brand, instead of the MCPD.