Accessing a Custom Configuration Section in .Net - vb.net

I am trying to access settings in my config file, which is a series of xml elements listed as such:
<databases>
<database name="DatabaseOne" Value="[value]" />
<database name="DatabaseTwo" Value="[value]" />
</databases>
Now I want to access it. I have set up classes like so:
Public Class DatabaseConfigurationHandler
Inherits ConfigurationSection
<ConfigurationProperty("Databases", IsDefaultCollection:=True)> _
Public ReadOnly Property Databases() As DatabaseCollection
Get
Return CType(Me("Databases"), DatabaseCollection)
End Get
End Property
End Class
Public Class DatabaseCollection
Inherits ConfigurationElementCollection
Protected Overloads Overrides Function CreateNewElement() As ConfigurationElement
Return (New Database())
End Function
Protected Overloads Overrides Function GetElementKey(ByVal element As ConfigurationElement) As Object
Return (CType(element, Database).DatabaseName)
End Function
End Class
Public Class Database
Inherits ConfigurationElement
<ConfigurationProperty("name", IsKey:=True, IsRequired:=True)> _
Public Property DatabaseName() As String
Get
Return Me("name").ToString()
End Get
Set(ByVal Value As String)
Me("name") = Value
End Set
End Property
<ConfigurationProperty("value", IsRequired:=True)> _
Public Property DatabaseValue() As String
Get
Return Me("value").ToString()
End Get
Set(ByVal Value As String)
Me("value") = Value
End Set
End Property
End Class
I want to be able get the element by it's name and return the value but I can't see to do that:
Dim config As New DatabaseConfigurationHandler
config = System.Configuration.ConfigurationManager.GetSection("databases/database")
Return config.Databases("DatabaseOne")
Am I missing some code, what am I doing wrong? Any other errors in the above?
Thanks.

Here's a cut and paste from something very similar I did a few days ago.
Config:
<ListConfigurations>
<lists>
<add Name="blah" EndpointConfigurationName="blah" ListName="blah" ConnectionString="blah" TableName="blah" FieldsCsv="blah" DbFieldsCsv="blah"/>
<add Name="blah2" EndpointConfigurationName="blah" ListName="blah" ConnectionString="blah" TableName="blah" FieldsCsv="blah" DbFieldsCsv="blah"/>
</lists>
</ListConfigurations>
Config section C#:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;
namespace App
{
/// <summary>
/// Individual list configuration
/// </summary>
class ListConfiguration : ConfigurationElement
{
[ConfigurationProperty("Name", IsKey = true, IsRequired = true)]
public string Name
{
get { return (string)this["Name"]; }
}
[ConfigurationProperty("EndpointConfigurationName", IsRequired = true)]
public string EndpointConfigurationName
{
get { return (string)this["EndpointConfigurationName"]; }
}
[ConfigurationProperty("ListName", IsRequired = true)]
public string ListName
{
get { return (string)this["ListName"]; }
}
[ConfigurationProperty("ConnectionString", IsRequired = true)]
public string ConnectionString
{
get { return (string)this["ConnectionString"]; }
}
[ConfigurationProperty("TableName", IsRequired = true)]
public string TableName
{
get { return (string)this["TableName"]; }
}
[ConfigurationProperty("FieldsCsv", IsRequired = true)]
public string FieldsCsv
{
get { return (string)this["FieldsCsv"]; }
}
[ConfigurationProperty("DbFieldsCsv", IsRequired = true)]
public string DbFieldsCsv
{
get { return (string)this["DbFieldsCsv"]; }
}
}
/// <summary>
/// Collection of list configs
/// </summary>
class ListConfigurationCollection : ConfigurationElementCollection
{
protected override ConfigurationElement CreateNewElement()
{
return new ListConfiguration();
}
protected override object GetElementKey(ConfigurationElement element)
{
return ((ListConfiguration)element).Name;
}
}
/// <summary>
/// Config section
/// </summary>
class ListConfigurationSection : ConfigurationSection
{
[ConfigurationProperty("lists")]
public ListConfigurationCollection Lists
{
get { return (ListConfigurationCollection)this["lists"]; }
}
}
}
And the code to pick it up from the main app:
ListConfigurationSection configSection = null;
try
{
configSection = ConfigurationManager.GetSection("ListConfigurations") as ListConfigurationSection;
}
catch (System.Configuration.ConfigurationErrorsException)
{
}

There isn't any good reason to design this kind of stuff by hand anymore. Rather, you should be using the Configuration Section Designer on CodePlex:
http://csd.codeplex.com/
Once installed, you can just add a new item to your project (a configuration section designer) and then add the elements and the constraints. I've found it VERY easy to use, and I will probably never write a piece of code for configuration files again.

You can use this configuration handler instead.. It will work for ALL custom configuration sections
public class XmlConfigurator : IConfigurationSectionHandler
{
public object Create(object parent,
object configContext, XmlNode section)
{
if (section == null)
throw new ArgumentNullException("section",
"Invalid or missing configuration section " +
"provided to XmlConfigurator");
XPathNavigator xNav = section.CreateNavigator();
if (xNav == null)
throw new ApplicationException(
"Unable to create XPath Navigator");
Type sectionType = Type.GetType((string)
(xNav).Evaluate("string(#configType)"));
XmlSerializer xs = new XmlSerializer(sectionType);
return xs.Deserialize(new XmlNodeReader(section));
}
}
Your config file then has to include a reference to the type that the represents the root element
<ConnectionConfig
configType="MyNamespace.ConnectionConfig, MyNamespace.AssmblyName" >
A sample config file might look like this:
<?xml version="1.0" encoding="utf-8" ?>
<ConnectionConfig
configType="MyNamespace.ConnectionConfig, MyNamespace.AssmblyName" >
<ConnCompanys>
<ConnCompany companyName="CompanyNameHere">
<ConnApps>
<ConnApp applicationName="Athena" vendorName="Oracle" >
<ConnSpecs>
<ConnSpec environments="DEV"
serverName="Athena"
port="1521"
catalog="DatabaseName"
logon="MyUserName"
password="%%552355%8234^kNfllceHGp55X5g==" />
<!-- etc...
And you will need to define the classes that each xml element maps to... using the appropriate XmlSerialization attributes ...
[XmlRoot("ConnectionConfig")]
public class ConnectionConfig
{
private ConnCompanys comps;
[XmlArrayItem(ElementName = "ConnCompany")]
public ConnCompanys ConnCompanys
{
get { return comps; }
set { comps = value; }
}
public ConnApp this[string CompanyName, string AppName]
{ get { return ConnCompanys[CompanyName][AppName]; } }
public ConnSpec this[string CompanyName, string AppName, APPENV env]
{
get
{
return ConnCompanys[CompanyName][AppName, env];
}
}
}
public class ConnCompanys : List<ConnCompany>
{
public ConnCompany this[string companyName]
{
get
{
foreach (ConnCompany comp in this)
if (comp.CompanyName == companyName)
return comp;
return null;
}
}
public bool Contains(string companyName)
{
foreach (ConnCompany comp in this)
if (comp.CompanyName == companyName)
return true;
return false;
}
}
public class ConnCompany
{
#region private state fields
private string compNm;
private ConnApps apps;
#endregion private state fields
#region public properties
[XmlAttribute(DataType = "string", AttributeName = "companyName")]
public string CompanyName
{
get { return compNm; }
set { compNm = value; }
}
[XmlArrayItem(ElementName = "ConnApp")]
public ConnApps ConnApps
{
get { return apps; }
set { apps = value; }
}
#endregion public properties
#region indexers
public ConnApp this[string applicationName]
{ get { return ConnApps[applicationName]; } }
public ConnSpec this[string applicationName, APPENV environment]
{
get
{
foreach (ConnSpec con in this[applicationName].ConnSpecs)
if (con.Environment == environment)
return con;
return null;
}
}
#endregion indexers
}
etc...

My VB isn't up to much sorry but here's how you do it in C#.
C#
public class AppState : IConfigurationSectionHandler
{
static AppState()
{
xmlNode myConfigNode = (XmlNode)ConfigurationManager.GetSection("databases");
}
public object Create(object parent, object context, XmlNode configSection) {
return configSection;
}
}
App.Config
<configuration>
<configSections>
<section name="databases" type="MyAssembly.AppState, MyAssembly" />
</configSections>
<databases>
<database name="DatabaseOne" Value="[value]" />
<database name="DatabaseTwo" Value="[value]" />
</databases>
</configuration>

You might be interested in using a ConfigurationElementCollection where T is the type of the child ConfigurationElements. You can find sample code in C# at http://devpinoy.org/blogs/jakelite/archive/2009/01/10/iconfigurationsectionhandler-is-dead-long-live-iconfigurationsectionhandler.aspx
Cheers!

There's a nice simple way of doing this demonstrated here also:
codeproject.com/KB/XML/xml_config_section.aspx

Related

Trouble with DataContractSerializer

I'm trying to make DataContract Serializer work with one of my class.
Here it is :
public class MyOwnObservableCollection<T> : ObservableCollection<T>, IDisposable
where T : IObjectWithChangeTracker, INotifyPropertyChanged
{
protected List<T> removedItems;
[DataMember]
public List<T> RemovedItems
{
get { return this.removedItems;}
set { this.removedItems = value;}
}
// Other code removed for simplification
// ...
//
}
It is important to understand that the RemovedItems list gets populated automatically when you remove an Item from the ObservableCollection.
Now serializing an instance of this class using the DataContractSerializer with one element in the removedItems list with the following code :
MyOwnObservableCollection<Test> _Test = new MyOwnObservableCollection<Test>();
DataContractSerializer dcs = new DataContractSerializer(typeof(MyOwnObservableCollection<Test>));
XmlWriterSettings settings = new XmlWriterSettings() { Indent = true };
string fileName = #"Test.xml";
Insurance atest = new Test();
atest.Name = #"sfdsfsdfsff";
_Test.Add(atest);
_Test.RemoveAt(0); // The Iitem in the ObservableCollection is moved to the RemovedItems List/
using (var w = XmlWriter.Create(fileName, settings))
{
dcs.WriteObject(w, _Test);
}
ends with nothing in the XML file :
<?xml version="1.0" encoding="utf-8"?>
<ArrayOfTest xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="MyNameSpace" />
Why is this public property ignored ? What have I missed here ?
TIA.
The problem here is that your class is derived from a collection, and as such, the DataContractSerializer serializes only its items, but not any extra properties, as stated here: No properties when using CollectionDataContract.
A workaround would be using the original (inherited) collection as a property, rather than inheriting from it:
public class MyOwnObservableCollection<T> : IDisposable
where T : IObjectWithChangeTracker, INotifyPropertyChanged
{
readonly ObservableCollection<T> originalCollection = new ObservableCollection<T>();
protected List<T> removedItems = = new List<T>();
[DataMember]
public List<T> RemovedItems
{
get { return this.removedItems;}
set { this.removedItems = value;}
}
[DataMember]
public ObservableCollection<T> OriginalCollection
{
get { return this.originalCollection; }
}
// ...
}

base class property always null when creating objects from xaml

I'm trying to instance an object(s) from xaml. The object's class inherits from a base class. Everything works good except that the a base class property ("Key") is not setting correctly from xaml. It's always null. The object's properties itself are set OK from xaml. Also when I set the Key property from code it sets fine.
I put a breakpoint on the closing bracket of the MainWindow method to view the object data. The hover details tells me the Key property is always null.
Any ideas what I'm doing wrong?
<?xml version="1.0" encoding="utf-8" ?>
<GroupUiItem xmlns="clr-namespace:Configurator.UiCore"
Key="key_grp1" UserName="grp1">
<ParameterUiItem Key="key_par1" UserName="par1"/>
<GroupUiItem Key="key_grp2" UserName="grp2">
<ParameterUiItem Key="key_par2" UserName="par2"/>
<ParameterUiItem Key="key_par3" UserName="par3"/>
</GroupUiItem>
<ParameterUiItem Key="key_par4" UserName="par4"/>
<ParameterUiItem Key="key_par5" UserName="par5"/>
<ParameterUiItem Key="key_par6" UserName="par6"/>
</GroupUiItem>
public partial class MainWindow : Window
{
public MainWindow()
{
GroupUiItem ConfigUi = new GroupUiItem();
InitializeComponent();
using (FileStream stream = new FileStream("XMLFile1.xaml", FileMode.Open, FileAccess.Read))
{
ConfigUi = XamlReader.Load(stream) as GroupUiItem;
}
ConfigUi.Key = "key_grp1"; // this works OK
CategoryList.ItemsSource = ConfigUi.Children;
}
}
// These are in the Configurator.UiCore namespace:
public class ConfiguratorUiItem
{
protected string _Key;
public string Key
{
get { return _Key; }
set { _Key = value; }
}
}
[ContentProperty("Children")]
public class GroupUiItem : ConfiguratorUiItem
{
private ObservableCollection<ConfiguratorUiItem> _Children = new ObservableCollection<ConfiguratorUiItem>();
public ObservableCollection<ConfiguratorUiItem> Children
{ get { return _Children; }
set { _Children = value; }
}
private string _UserName;
public string UserName
{ get { return _UserName; }
set { _UserName = value; }
}
}
public class ParameterUiItem : ConfiguratorUiItem
{
private string _ParameterType;
public string ParameterType
{
get { return _ParameterType; }
set { _ParameterType = value; }
}
private string _UserName;
public string UserName
{
get { return _UserName; }
set { _UserName = value; }
}
}
OK figured out my problem. Noob mistake. Needed to set build action to None and copy always. I had build action set to a page so it wasn't a loose xaml and wasn't updating to appropriate folder. I copied the xaml file to output directory manually when I first couldn't figure out the problem. This caused the program to always use the old file.
When I did this also had to add ";assembly=Configurator" to the end of the xmlns so that it now reads: "xmlns="clr-namespace:Configurator.UiCore;assembly=Configurator". Then it worked.

NHibernate: Custom Property Accessor's Get and Set methods not being called

I'm attempting to map a database field ("LS_RECNUM") possible values of NULL, 'M' and 'F' to a property with a Gender enumeration type.
The mapping looks like this:
Map(x => x.Gender).Column("LS_GENDER").Access.Using<GenderPropertyAccessor>();
...and the GenderPropertyAccessor class looks like this:
using System;
using System.Collections;
using System.Reflection;
using Kctc;
using NHibernate.Engine;
using NHibernate.Properties;
public class GenderPropertyAccessor : IPropertyAccessor
{
#region Setter
private class GenderGetterSetter : IGetter, ISetter
{
PropertyInfo _property;
public GenderGetterSetter(PropertyInfo property)
{
if (property == null) throw new ArgumentNullException("property");
if (property.PropertyType != typeof(Gender)) throw new ArgumentException("property");
_property = property;
}
public void Set(object target, object value) //Convert string to enum
{
_property.SetValue(target, GetGenderFromString(value), null);
}
public object Get(object target) //Convert enum back to string
{
Gender gender = (Gender)_property.GetValue(target, null);
return SetGenderToString(gender);
}
/// <summary>
/// Interprets the supplied string as a gender.
/// </summary>
/// <param name="strGender">The gender as either 'F' or 'M'.</param>
/// <returns></returns>
private Gender GetGenderFromString(object strGender)
{
if (strGender == null) return Gender.Unknown;
switch (strGender.ToString().ToLower())
{
case "f":
return Gender.Female;
case "m":
return Gender.Male;
default:
return Gender.Unknown;
}
}
/// <summary>
/// Sets the supplied Gender to the appropriate 'M' or 'F' value.
/// </summary>
/// <param name="objGender">The gender.</param>
/// <returns></returns>
private string SetGenderToString(object objGender)
{
Gender gender = (Gender) objGender;
switch (gender)
{
case Gender.Female:
return "F";
case Gender.Male:
return "M";
default:
return null;
}
}
public MethodInfo Method
{
get { return null; }
}
public string PropertyName
{
get { return _property.Name; }
}
public object GetForInsert(object owner, IDictionary mergeMap, ISessionImplementor session)
{
return Get(owner);
}
public Type ReturnType
{
get { return typeof(byte[]); }
}
}
#endregion
public IGetter GetGetter(Type theClass, string propertyName)
{
return new GenderGetterSetter(theClass.GetProperty(propertyName));
}
public ISetter GetSetter(Type theClass, string propertyName)
{
return new GenderGetterSetter(theClass.GetProperty(propertyName));
}
public bool CanAccessThroughReflectionOptimizer
{
get { return false; }
}
}
Not being particularly familiar with reflection, I'm not at all sure that the Get and Set methods have been implemented correctly.
When I try this, I still get an error 'Can't parse F as Gender'. I've tried debugging the GenderPropertyAccessor class. The relevant line (shown above) in the mapping file is executing correctly, as is the constructor for the GenderGetterSetter class, but the Get and Set methods are never called!!!
Can anyone tell me what I might be doing wrong?
I would use an implementation of IUserType for this. Here's a good simple example. In the NullSafeGet and NullSafeSet methods you will mutate the string to an enum and back, respectively. It's also critical that your Equals implementation is correct in order for NHibernate to detect changes.
Mapping the property to use a custom user type is easy:
Map(x => x.Gender).Column("LS_GENDER").CustomType(typeof(MyUserType));

WorkItemChangedEvent and AddedRelations field

I am trying to capture links that were added to a work item in TFS by catching WorkItemChangedEvent via TFS services. Here is the relevant XML part of the message that comes through:
<AddedRelations><AddedRelation><WorkItemId>8846</WorkItemId></AddedRelation></AddedRelations>
This is declared as a field in WorkItemChangedEvent class that should be deserialized into object upon receiving the event:
public partial class WorkItemChangedEvent
{
private string[] addedRelations;
/// <remarks/>
[XmlArrayItemAttribute("WorkItemId", IsNullable = false)]
public string[] AddedRelations
{
get { return this.addedRelations; }
set { this.addedRelations = value; }
}
}
I cannot figure out why the AddedRelations does not get deserialized properly.
I can only suspect that the object structure does not match the XML schema.
I have changed the structure of my WorkItemChangedEvent class a little bit to match the XML:
public partial class WorkItemChangedEvent
{
private AddedRelation[] addedRelations;
/// <remarks/>
[XmlArrayItemAttribute("AddedRelation", IsNullable = false)]
public AddedRelation[] AddedRelations
{
get { return this.addedRelations; }
set { this.addedRelations = value; }
}
[GeneratedCodeAttribute("xsd", "2.0.50727.42")]
[SerializableAttribute()]
[DebuggerStepThroughAttribute()]
[DesignerCategoryAttribute("code")]
[XmlTypeAttribute(Namespace = "")]
public partial class AddedRelation
{
#region Fields
private string workItemId;
#endregion
/// <remarks/>
public string WorkItemId
{
get { return this.workItemId; }
set { this.workItemId = value; }
}
}
}
I still think that there must be some logic behind the original solution since it was designed by TFS authors (MS)? Anyway I am glad it works now and that I answered my question first ;]

Fluent nHibernate Automapping not creating Plural table name

I have two tables, Locations and Facilities
They map to two classes,
public Location : Entity
{
//properties
}
public Facility : Entity
{
public virtual Location Location { get; set; }
}
Everything works just dandy, until I change facility to this
public Facility : Location
{
}
Now I get an exception from nHibernate saying
NHibernate.ADOException was unhandled by user code
Message=could not execute query
InnerException: System.Data.SqlClient.SqlException
Message=Invalid object name 'Facility'.
For some reason it is not creating the plural name of the table into the sql string.
Thanks for any help!
EDIT
This is my current TableNameConvention
public class TableNameConvention : IClassConvention
{
public void Apply(FluentNHibernate.Conventions.Instances.IClassInstance instance)
{
instance.Table(Inflector.Net.Inflector.Pluralize(instance.EntityType.Name));
}
}
When Facility inherits from Entity, the Facility does run through this method. When it inherits from Location, it does not
Edit 2
Figured I'd post everything...
public class AutoPersistenceModelGenerator : IAutoPersistenceModelGenerator
{
#region IAutoPersistenceModelGenerator Members
public AutoPersistenceModel Generate()
{
var mappings = new AutoPersistenceModel();
mappings.AddEntityAssembly(typeof(Person).Assembly).Where(GetAutoMappingFilter);
mappings.Conventions.Setup(GetConventions());
mappings.Setup(GetSetup());
mappings.IgnoreBase<Entity>();
mappings.IgnoreBase(typeof(EntityWithTypedId<>));
mappings.UseOverridesFromAssemblyOf<AutoPersistenceModelGenerator>();
return mappings;
}
#endregion
private Action<AutoMappingExpressions> GetSetup()
{
return c =>
{
c.FindIdentity = type => type.Name == "Id";
};
}
private Action<IConventionFinder> GetConventions()
{
return c =>
{
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.ForeignKeyConvention>();
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.HasManyConvention>();
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.HasManyToManyConvention>();
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.ManyToManyTableNameConvention>();
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.PrimaryKeyConvention>();
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.ReferenceConvention>();
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.TableNameConvention>();
};
}
/// <summary>
/// Provides a filter for only including types which inherit from the IEntityWithTypedId interface.
/// </summary>
private bool GetAutoMappingFilter(Type t)
{
return t.GetInterfaces().Any(x =>
x.IsGenericType &&
x.GetGenericTypeDefinition() == typeof(IEntityWithTypedId<>));
}
}
Have you set a convention?
public class TableNameConvention : IClassConvention
{
public void Apply(FluentNHibernate.Conventions.Instances.IClassInstance instance)
{
string typeName = instance.EntityType.Name;
instance.Table(Inflector.Net.Inflector.Pluralize(typeName));
}
}
This is an old question, but for the sake of others who stumble upon this looking for an answer, you can also create a convention that uses the built-in PluralizationService that comes with EF:
public class TableNameConvention : IClassConvention
{
public void Apply(IClassInstance instance)
{
string typeName = instance.EntityType.Name;
instance.Table(PluralizationService.CreateService(CultureInfo.CurrentCulture).Pluralize(typeName));
}
}