How to publish wmi classes in .net?
Question
I've created a seperate assembly with a class that is intended to be published through wmi. Then I've created a windows forms app that references that assembly and attempts to publish the class. When I try to publish the class, I get an exception of type System.Management.Instrumentation.WmiProviderInstallationException. The message of the exception says "Exception of type 'System.Management.Instrumentation.WMIInfraException' was thrown.". I have no idea what this means. I've tried .Net2.0 and .Net3.5 (sp1 too) and get the same results.
Below is my wmi class, followed by the code I used to publish it.
//Interface.cs in assembly WMI.Interface.dll
using System;
using System.Collections.Generic;
using System.Text;
[assembly: System.Management.Instrumentation.WmiConfiguration(@"root\Test",
HostingModel =
System.Management.Instrumentation.ManagementHostingModel.Decoupled)]
namespace WMI
{
[System.ComponentModel.RunInstaller(true)]
public class MyApplicationManagementInstaller :
System.Management.Instrumentation.DefaultManagementInstaller { }
[System.Management.Instrumentation.ManagementEntity(Singleton = true)]
[System.Management.Instrumentation.ManagementQualifier("Description",
Value = "Obtain processor information.")]
public class Interface
{
[System.Management.Instrumentation.ManagementBind]
public Interface()
{
}
[System.Management.Instrumentation.ManagementProbe]
[System.Management.Instrumentation.ManagementQualifier("Descriiption",
Value="The number of processors.")]
public int ProcessorCount
{
get { return Environment.ProcessorCount; }
}
}
}
//Button click in windows forms application to publish class
try
{
System.Management.Instrumentation.InstrumentationManager.Publish(new
WMI.Interface());
}
catch (System.Management.Instrumentation.InstrumentationException
exInstrumentation)
{
MessageBox.Show(exInstrumentation.ToString());
}
catch (System.Management.Instrumentation.WmiProviderInstallationException
exProvider)
{
MessageBox.Show(exProvider.ToString());
}
catch (Exception exPublish)
{
MessageBox.Show(exPublish.ToString());
}
Solution
I used gacutil - installutil to to test your class (as a dll). The gacutil part worked, but installutil (actually mofcomp) complained about a syntax error:
...
error SYNTAX 0X80044014: Unexpected character in class name (must be an identifier)
Compiler returned error 0x80044014
...
So I changed the class name to 'MyInterface' the installutil part worked, but the class didn't return any instances. Finally I changed the hosting model to Network Service and got it to work.
OTHER TIPS
To summarize, this is the final code that works:
Provider class, in it's own assembly:
// the namespace used for publishing the WMI classes and object instances
[assembly: Instrumented("root/mytest")]
using System;
using System.Collections.Generic;
using System.Text;
using System.Management;
using System.Management.Instrumentation;
using System.Configuration.Install;
using System.ComponentModel;
namespace WMITest
{
[InstrumentationClass(System.Management.Instrumentation.InstrumentationType.Instance)]
//[ManagementEntity()]
//[ManagementQualifier("Description",Value = "Obtain processor information.")]
public class MyWMIInterface
{
//[System.Management.Instrumentation.ManagementBind]
public MyWMIInterface()
{
}
//[ManagementProbe]
//[ManagementQualifier("Descriiption", Value="The number of processors.")]
public int ProcessorCount
{
get { return Environment.ProcessorCount; }
}
}
/// <summary>
/// This class provides static methods to publish messages to WMI
/// </summary>
public static class InstrumentationProvider
{
/// <summary>
/// publishes a message to the WMI repository
/// </summary>
/// <param name="MessageText">the message text</param>
/// <param name="Type">the message type</param>
public static MyWMIInterface Publish()
{
// create a new message
MyWMIInterface pInterface = new MyWMIInterface();
Instrumentation.Publish(pInterface);
return pInterface;
}
/// <summary>
/// revoke a previously published message from the WMI repository
/// </summary>
/// <param name="Message">the message to revoke</param>
public static void Revoke(MyWMIInterface pInterface)
{
Instrumentation.Revoke(pInterface);
}
}
/// <summary>
/// Installer class which will publish the InfoMessage to the WMI schema
/// (the assembly attribute Instrumented defines the namespace this
/// class gets published too
/// </summary>
[RunInstaller(true)]
public class WMITestManagementInstaller :
DefaultManagementProjectInstaller
{
}
}
Windows forms application main form, publishes provider class:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Management;
using System.Management.Instrumentation;
namespace WMI
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
WMITest.MyWMIInterface pIntf_m;
private void btnPublish_Click(object sender, EventArgs e)
{
try
{
pIntf_m = WMITest.InstrumentationProvider.Publish();
}
catch (ManagementException exManagement)
{
MessageBox.Show(exManagement.ToString());
}
catch (Exception exPublish)
{
MessageBox.Show(exPublish.ToString());
}
}
}
}
Test web application, consumer:
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Management.Instrumentation;
using System.Management;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
ManagementClass pWMIClass = null;
pWMIClass = new ManagementClass(@"root\interiorhealth:MyWMIInterface");
lblOutput.Text = "ClassName: " + pWMIClass.ClassPath.ClassName + "<BR/>" +
"IsClass: " + pWMIClass.ClassPath.IsClass + "<BR/>" +
"IsInstance: " + pWMIClass.ClassPath.IsInstance + "<BR/>" +
"IsSingleton: " + pWMIClass.ClassPath.IsSingleton + "<BR/>" +
"Namespace Path: " + pWMIClass.ClassPath.NamespacePath + "<BR/>" +
"Path: " + pWMIClass.ClassPath.Path + "<BR/>" +
"Relative Path: " + pWMIClass.ClassPath.RelativePath + "<BR/>" +
"Server: " + pWMIClass.ClassPath.Server + "<BR/>";
//GridView control
this.gvProperties.DataSource = pWMIClass.Properties;
this.gvProperties.DataBind();
//GridView control
this.gvSystemProperties.DataSource = pWMIClass.SystemProperties;
this.gvSystemProperties.DataBind();
//GridView control
this.gvDerivation.DataSource = pWMIClass.Derivation;
this.gvDerivation.DataBind();
//GridView control
this.gvMethods.DataSource = pWMIClass.Methods;
this.gvMethods.DataBind();
//GridView control
this.gvQualifiers.DataSource = pWMIClass.Qualifiers;
this.gvQualifiers.DataBind();
}
}
}