SPWebConfigModification. Some links to start with: http://panvega.wordpress.com/2009/09/02/using-spwebconfigmodification-within-a-feature-receiver/ http://www.onedotnetway.com/get-name-of-current-executing-assembly-in-c/ http://blogs.devhorizon.com/reza/?p=459 http://ikarstein.wordpress.com/2010/09/02/add-web-config-modification-with-powershell-spwebconfigmodification/ http://msdn.microsoft.com/en-us/library/bb861909.aspx

public override void FeatureActivated(SPFeatureReceiverProperties properties)
{
	var webapp = parent as SPWebApplication;
	if (webapp != null)
	{
		var mod1 = GetWebControlsConfigMod();
		webapp.WebConfigModifications.Add(mod1);
		var mod2 = GetConStringConfigMod();
		webapp.WebConfigModifications.Add(mod2);
		SaveChanges(webapp);
	}
	else
	{
		Log.Warning("no modifications to webapp are done");
	}
}

public override void FeatureDeactivating(SPFeatureReceiverProperties properties)
{
	var webapp = parent as SPWebApplication;
	if (webapp != null)
	{
		var mod = GetWebControlsConfigMod();
		var modsCollection = webapp.WebConfigModifications;
		var modToDelete =
			(from m in modsCollection
			 where m.Value.Equals(mod.Value, StringComparison.InvariantCultureIgnoreCase)
			 select m).FirstOrDefault();
		if (modToDelete != null)
		{
			modsCollection.Remove(modToDelete);
			SaveChanges(webapp);
		}
	}
}
private static void SaveChanges(SPPersistedObject webapp)
{
	var service = webapp.Farm.Services.GetValue();
	service.ApplyWebConfigModifications();
	webapp.Update();
}

private static SPWebConfigModification GetWebControlsConfigMod()
{
	var assembly = System.Reflection.Assembly.GetAssembly(typeof(WebControls.OfficeEditor));
	var ass = assembly.FullName;
	var @namespace = assembly.GetName().Name + ".WebControls";
	var value = string.Format("", ass,
							  @namespace);
	const string path = "configuration/SharePoint/SafeControls";
	var mod = new SPWebConfigModification
	{
		Path = path,
		Name = "JustaName1",
		Sequence = 0,
		Owner = @namespace,
		Type = SPWebConfigModification.SPWebConfigModificationType.EnsureChildNode,
		Value = value
	};
	return mod;
}

private static SPWebConfigModification GetConStringConfigMod()
{
	const string name = "ContosoConString";
	const string conString =
		"Data Source=db.contoso.com;Initial Catalog=contoso\_db;Persist Security Info=True;User ID=contoso\_Contributor;Password=contoso";
	var mod = new SPWebConfigModification
	  {
		  Name = "JustaName2",
		  Path = "configuration/connectionStrings",
		  Owner = "contoso\_connectionstrings",
		  Type = SPWebConfigModification.SPWebConfigModificationType.EnsureChildNode,
		  Value = String.Format("", name, conString)
	  };
	return mod;
}
```Powershell:

#ADDING asnp microsoft.sharepoint.powershell $url = “http://contoso” $app = Get-SPWebApplication $url $name = “ContosoConString”; $conString = “Data Source=db.contoso.com;Initial Catalog=contoso_db;Persist Security Info=True;User ID=contoso_Contributor;Password=contoso”; $mod = new-object Microsoft.SharePoint.Administration.SPWebConfigModification $mod.Name = “JustName2” $mod.Path = “configuration/connectionStrings” $mod.Owner = “User Name” $mod.Type = 0 #for the enum value “SPWebConfigModification.SPWebConfigModificationType.EnsureChildNode” $mod.Value = ‘’ -f $name, $conString $app.WebConfigModifications.Add($mod) $service = [Microsoft.SharePoint.Administration.SPWebService]::ContentService $service.ApplyWebConfigModifications() $app.Update() #ADDING snapin asnp microsoft.sharepoint.powershell

$url = “http://contoso” $app = Get-SPWebApplication $url

#SafeControl $assembly = “Contoso.SP, Version=1.0.0.0, Culture=neutral, PublicKeyToken=20c0327f8b01d979” $namespace = “Contoso.SP.WebControls” $mod = new-object Microsoft.SharePoint.Administration.SPWebConfigModification $mod.Name = “ContosoSafeControls” $mod.Path = “configuration/SharePoint/SafeControls” $mod.Owner = “Contoso” $mod.Type = 0 #for the enum value “SPWebConfigModification.SPWebConfigModificationType.EnsureChildNode” $mod.Value = ‘’ -f $assembly, $namespace $app.WebConfigModifications.Add($mod)

#applying changes $service = [Microsoft.SharePoint.Administration.SPWebService]::ContentService $service.ApplyWebConfigModifications() $app.Update()

#REMOVING asnp microsoft.sharepoint.powershell $app = Get-SPWebApplication http://contoso $modCol = $app.WebConfigModifications $mod = $modCol| Where { $_.Owner.Equals(“User Name”) } $modCol.Remove($mod) $service = [Microsoft.SharePoint.Administration.SPWebService]::ContentService $service.ApplyWebConfigModifications() $app.Update()

#if you want to clear all web.config mods associated with the web app: $modCol = $app.WebConfigModifications while ($modCol -ne 0) { $modCol.Remove($modCol[0]) } $service.ApplyWebConfigModifications() $app.Update()

##### Add the first connectionString

I encountered a problem adding the first connection string by this script. It just didn't work. [The solution is to add the parent element "connectionStrings"](http://stackoverflow.com/questions/4888307/problem-changing-web-config-in-sharepoint).

## Comments from Wordpress.com


#### 
[scriptcs and SharePoint. How SharePoint can benefit? | Bool Tech](http://tech.bool.se/scriptcs-and-sharepoint-how-sharepoint-can-benefit/ "") - <time datetime="2013-10-15 17:00:43">Oct 2, 2013</time>

\[…\] You don’t need to rewrite your C# code to PowerShell. It saves time. Often one can see two solutions: one for C#, one for PowerShell, example. \[…\]
<hr />

• PowerShell
• Sharepoint
• sharepoint
• web.config