Using ConfigurationManager & custom configuration sections

Hi there,

I'm trying to use the ConfigurationSection class from the ConfigurationManager because I need to store some repeated custom configuration settings that have multiple properties.

Using C# Express Edition 2005 Beta 2, I've built the example below based on an example I downloaded from the Internet. It compiles OK but when I run it I get the following error message:

An error occurred creating the configuration section handler for systems: Could not load type 'SystemsSection' from assembly 'ConfigConsoleApplication'. (C:\Documents and Settings\Jean\Local Settings\Application Data\Temporary Projects\ConfigConsoleApplication\bin\Debug\ConfigConsoleApplication.EXE.config line 4)

I newbie to C#, I've been head-butting the screen all day yesterday - I suspect there is something blindingly obvious that I've missed but I don't know what Sad

Thanks & regards,

J B Li
London

.NET Development21

I believe that the type name must also include the namespace. Try using type="ConfigConsoleApplication.SystemsSection,ConfigConsoleApplication" instead.

Hi David,

[CLAPS HAND ON FOREHEAD] Thanks for that - someone else also e-mailed me with the same solution ! And of course it works Big Smile

Here's the solution again with your correction in place for the benefit of anyone else looking for a small working example. I removed the redundant "default" property from my original posting and added code to output the configuration data.

Thanks again & regards,

Jean (<-- it's a French name).

Hi,

I am trying to work through the example you provided, and I cannot get it to compile. I keep getting the following exception:

Error 18 'ConfigConsoleApplication.SystemsCollection.CollectionType': cannot change access modifiers when overriding 'public' inherited member 'System.Configuration.ConfigurationElementCollection.CollectionType' C:\TheCloset\CustomConfigSample\CustomConfigSample\Program.cs 39 57 CustomConfigSample

Do you have any idea what would be causing this I have included the reference to the System.configuration dll, and have made no other changes to the code.

Thanks,

Jim Martin.

Looks like the issue is due to using the RTM version of Visual Studio. MS changes a few items.

Firts, I needed to change the

protected override ConfigurationElementCollectionType CollectionType

to

public override ConfigurationElementCollectionType CollectionType

After this, several of the attribute parameter names were changed in the final release. I am including the code as I was able to get it compiling.

Thanks to all who contributed to this. It has been very helpful to me!

Jim.

-------------------------------------------------------
App.Config

< xml version="1.0" encoding="utf-8" >

</configSections>

</systems>

</configuration>

-----------------------------------------------------
Program.cs

using System;

using System.Collections.Generic;

using System.Collections.Specialized;

using System.Configuration; // remember to add reference in project

using System.Reflection;

using System.Text;

namespace ConfigConsoleApplication

{

public sealed class SystemsSection : ConfigurationSection

{

public SystemsSection()

{

}

[ConfigurationProperty( "", IsDefaultCollection = true )]

public SystemsCollection Systems

{

get

{

return (SystemsCollection)base[""];

}

public sealed class SystemsCollection : ConfigurationElementCollection

{

protected override ConfigurationElement CreateNewElement()

{

return new SystemElement();

}

protected override object GetElementKey( ConfigurationElement element )

{

return ((SystemElement)element).Name;

}

public override ConfigurationElementCollectionType CollectionType

{

get

{

return ConfigurationElementCollectionType.BasicMap;

}

protected override string ElementName

{

get

{

return "system";

}

public sealed class SystemElement : ConfigurationElement

{

[ConfigurationProperty( "name", IsKey = true, IsRequired = true )]

public string Name

{

get

{

return (string)base["name"];

}

set

{

base["name"] = value;

}

[ConfigurationProperty( "server", IsRequired = true )]

public string Server

{

get

{

return (string)base["server"];

}

set

{

base["server"] = value;

}

[ConfigurationProperty( "database", IsRequired = true )]

public string Database

{

get

{

return (string)base["database"];

}

set

{

base["database"] = value;

}

public override string ToString()

{

string output = "SystemElement :\n";

output += string.Format( "Name = {0}\n", Name );

output += string.Format( "Server = {0}\n", Server );

output += string.Format( "Database = {0}\n", Database );

return output;

}

public class Program

{

static void Main( string[] args )

{

SystemsSection sysSection = ConfigurationManager.GetSection( "systems" )

as SystemsSection;

SystemsCollection oneCollection = sysSection.Systems;

foreach( SystemElement oneElement in oneCollection )

{

Console.WriteLine( oneElement.ToString() );

}

Hi,

I can read the following data.

Regs

Satya

Thanks for the thread, you guys helped me create a custom config section for my VB.NET project, so I thought I would post the translated code in case anyone needs it

Imports system

Imports System.configuration

Imports System.Collections.Generic

Imports System.Collections.Specialized

Imports System.Reflection

Imports System.text

Namespace ConfigConsoleApplication

Public Class SystemsSection

Inherits ConfigurationSection

Public Sub PrintSettings()

End Sub

<ConfigurationProperty("", IsDefaultCollection:=True)> _

Public ReadOnly Property Systems() As SystemsCollection

Get

Return CType(Me(""), SystemsCollection)

End Get

End Property

End Class

Public Class SystemsCollection

Inherits ConfigurationElementCollection

Protected Overloads Overrides Function CreateNewElement() As System.Configuration.ConfigurationElement

Return New SystemElement()

End Function

Protected Overrides Function GetElementKey(ByVal element As System.Configuration.ConfigurationElement) As Object

Return CType(element, SystemElement).Name

End Function

Public Overrides ReadOnly Property CollectionType() As System.Configuration.ConfigurationElementCollectionType

Get

Return ConfigurationElementCollectionType.BasicMap

End Get

End Property

Protected Overrides ReadOnly Property ElementName() As String

Get

Return "system"

End Get

End Property

End Class

Public Class SystemElement

Inherits ConfigurationElement

<ConfigurationProperty("name", IsKey:=True, isRequired:=True)> _

Public Property Name() As String

Get

Return Me("name")

End Get

Set(ByVal value As String)

Me("name") = value

End Set

End Property

<ConfigurationProperty("server", isRequired:=True)> _

Public Property Server() As String

Get

Return Me("server")

End Get

Set(ByVal value As String)

Me("server") = value

End Set

End Property

<ConfigurationProperty("database", isRequired:=True)> _

Public Property Database() As String

Get

Return Me("database")

End Get

Set(ByVal value As String)

Me("database") = value

End Set

End Property

Public Overrides Function ToString() As String

Dim output As String

output = "SystemElement :\n"

output += String.Format("Name = {0}\n", Name)

output += String.Format("Server = {0}\n", Server)

output += String.Format("Database = {0}\n", Database)

Return output

End Function

End Class

End Namespace

hi, Jim Martin & Jean

Your codes are really cool! They has been very helpful to me! Now i wanna do something a little different. i wish i can use a customized configuration file "myapp.config" , whose content is same as the file "App.config".

myapp.config:

< xml version="1.0" encoding="utf-8" >
<configuration>
<configSections>
<section name="systems" type="ConfigConsoleApplication.SystemsSection, ConfigConsoleApplication" />
</configSections>
<systems>
<system name="Production" server="PRODSERVER" database="Prod" />
<system name="Demo" server="DEMOSERVER" database="Demo" />
<system name="Testing" server="TESTSERVER" database="Test" />
<system name="Development" server="DEVSERVER" database="DEV" />
</systems>
</configuration>

MySampleCode scriptlet:

ExeConfigurationFileMap fileMap = new ExeConfigurationFileMap();

Configuration cfg = ConfigurationManager.OpenMappedExeConfiguration(fileMap, ConfigurationUserLevel.None);
SystemsSection sysSection = cfg.GetSection("systems") as SystemsSection;
......

Why the variant "sysSection" is null Do you have any idea about it Thank you guys in advance!!!

Eric G Wang

hi Satya,

Can you show me some Sample Codes Thanks a lot!!!

Eric G Wang