Environment Variables <environmentVariables>


The <environmentVariables> element of the <applicationPools>/<add> element specifies a list of environment variables that Internet Information Services (IIS) 10 will pass to a worker process when an application is launched. The <environmentVariables> element contains a collection of <add> elements which define the individual name/value pairs for each environment variable.


Version Notes
IIS 10.0 The <environmentVariables> element was introduced in IIS 10.
IIS 8.0 N/A
IIS 7.5 N/A
IIS 7.0 N/A
IIS 6.0 N/A


The <environmentVariables> element is included in the default installation of IIS 10.

How To

There is no user interface for setting the environment variables for IIS 10. For examples of how to set the environment variables programmatically, see the Code Samples section of this document.




Child Elements

Element Description
add Optional element.

Adds an environment variable to the collection of environment variables.
remove Optional element.

Removes an environment variable from the collection of environment variables.

Configuration Sample

The following example adds an environment variable to an application pool.

   <add name="Contoso" managedRuntimeVersion="v4.0" managedPipelineMode="Classic">
         <add name="foo" value="bar" />

Sample Code

The following examples demonstrate how to add a name/value pair to the collection of environment variables.


appcmd.exe set config -section:system.applicationHost/applicationPools /+"[name='Contoso'].environmentVariables.[name='foo',value='bar']" /commit:apphost


using System;
using System.Text;
using Microsoft.Web.Administration;

internal static class Sample {
   private static void Main() {
      using(ServerManager serverManager = new ServerManager()) { 
         Configuration config = serverManager.GetApplicationHostConfiguration();
         ConfigurationSection applicationPoolsSection = config.GetSection("system.applicationHost/applicationPools");
         ConfigurationElementCollection applicationPoolsCollection = applicationPoolsSection.GetCollection();
         ConfigurationElement addElement = FindElement(applicationPoolsCollection, "add", "name", @"Contoso");
         if (addElement == null) throw new InvalidOperationException("Element not found!");
         ConfigurationElementCollection environmentVariablesCollection = addElement.GetCollection("environmentVariables");
         ConfigurationElement addElement1 = environmentVariablesCollection.CreateElement("add");
         addElement1["name"] = @"foo";
         addElement1["value"] = @"bar";
   private static ConfigurationElement FindElement(ConfigurationElementCollection collection, string elementTagName, params string[] keyValues)
      foreach (ConfigurationElement element in collection)
         if (String.Equals(element.ElementTagName, elementTagName, StringComparison.OrdinalIgnoreCase))
            bool matches = true;
            for (int i = 0; i < keyValues.Length; i += 2)
               object o = element.GetAttributeValue(keyValues[i]);
               string value = null;
               if (o != null)
                  value = o.ToString();
               if (!String.Equals(value, keyValues[i + 1], StringComparison.OrdinalIgnoreCase))
                  matches = false;
            if (matches)
               return element;
      return null;


Imports System
Imports System.Text
Imports Microsoft.Web.Administration

Class Sample
   Private Shared Sub Main()
      Dim serverManager As ServerManager = New ServerManager
      Dim config As Configuration = serverManager.GetApplicationHostConfiguration
      Dim applicationPoolsSection As ConfigurationSection = config.GetSection("system.applicationHost/applicationPools")
      Dim applicationPoolsCollection As ConfigurationElementCollection = applicationPoolsSection.GetCollection
      Dim addElement As ConfigurationElement = FindElement(applicationPoolsCollection, "add", "name", "Contoso")
      If (addElement Is Nothing) Then
         Throw New InvalidOperationException("Element not found!")
      End If
      Dim environmentVariablesCollection As ConfigurationElementCollection = addElement.GetCollection("environmentVariables")
      Dim addElement1 As ConfigurationElement = environmentVariablesCollection.CreateElement("add")
      addElement1("name") = "foo"
      addElement1("value") = "bar"
   End Sub

   Private Function FindElement(ByVal collection As ConfigurationElementCollection, ByVal elementTagName As String, ByVal ParamArray keyValues() As String) As ConfigurationElement
      For Each element As ConfigurationElement In collection
         If String.Equals(element.ElementTagName, elementTagName, StringComparison.OrdinalIgnoreCase) Then
            Dim matches As Boolean = True
            Dim i As Integer
            For i = 0 To keyValues.Length - 1 Step 2
               Dim o As Object = element.GetAttributeValue(keyValues(i))
               Dim value As String = Nothing
               If (Not (o) Is Nothing) Then
                  value = o.ToString
               End If
               If Not String.Equals(value, keyValues((i + 1)), StringComparison.OrdinalIgnoreCase) Then
                  matches = False
                  Exit For
               End If
            If matches Then
               Return element
            End If
         End If
      Return Nothing
   End Function

End Class


var adminManager = new ActiveXObject('Microsoft.ApplicationHost.WritableAdminManager');
adminManager.CommitPath = "MACHINE/WEBROOT/APPHOST";
var applicationPoolsSection = adminManager.GetAdminSection("system.applicationHost/applicationPools", "MACHINE/WEBROOT/APPHOST");
var applicationPoolsCollection = applicationPoolsSection.Collection;
var addElementPos = FindElement(applicationPoolsCollection, "add", ["name", "Contoso"]);
if (addElementPos == -1) throw "Element not found!";

var addElement = applicationPoolsCollection.Item(addElementPos);
var environmentVariablesCollection = addElement.ChildElements.Item("environmentVariables").Collection;

var addElement1 = environmentVariablesCollection.CreateNewElement("add");
addElement1.Properties.Item("name").Value = "foo";
addElement1.Properties.Item("value").Value = "bar";


function FindElement(collection, elementTagName, valuesToMatch) {
   for (var i = 0; i < collection.Count; i++) {
      var element = collection.Item(i);
      if (element.Name == elementTagName) {
         var matches = true;
         for (var iVal = 0; iVal < valuesToMatch.length; iVal += 2) {
            var property = element.GetPropertyByName(valuesToMatch[iVal]);
            var value = property.Value;
            if (value != null) {
               value = value.toString();
            if (value != valuesToMatch[iVal + 1]) {
               matches = false;
         if (matches) {
            return i;
   return -1;


Set adminManager = CreateObject("Microsoft.ApplicationHost.WritableAdminManager")
adminManager.CommitPath = "MACHINE/WEBROOT/APPHOST"
Set applicationPoolsSection = adminManager.GetAdminSection("system.applicationHost/applicationPools", "MACHINE/WEBROOT/APPHOST")
Set applicationPoolsCollection = applicationPoolsSection.Collection

addElementPos = FindElement(applicationPoolsCollection, "add", Array("name", "Contoso"))
If addElementPos = -1 Then
   WScript.Echo "Element not found!"
End If

Set addElement = applicationPoolsCollection.Item(addElementPos)
Set environmentVariablesCollection = addElement.ChildElements.Item("environmentVariables").Collection

Set addElement1 = environmentVariablesCollection.CreateNewElement("add")
addElement1.Properties.Item("name").Value = "foo"
addElement1.Properties.Item("value").Value = "bar"


Function FindElement(collection, elementTagName, valuesToMatch)
   For i = 0 To CInt(collection.Count) - 1
      Set element = collection.Item(i)
      If element.Name = elementTagName Then
         matches = True
         For iVal = 0 To UBound(valuesToMatch) Step 2
            Set property = element.GetPropertyByName(valuesToMatch(iVal))
            value = property.Value
            If Not IsNull(value) Then
               value = CStr(value)
            End If
            If Not value = CStr(valuesToMatch(iVal + 1)) Then
               matches = False
               Exit For
            End If
         If matches Then
            Exit For
         End If
      End If
   If matches Then
      FindElement = i
      FindElement = -1
   End If
End Function