How to View SharePoint App Web Site Contents

I know most of the SharePoint App developers or users would definitely look for site contents of an App Web and List Settings in an App Web. But it turns out that there is no direct way to access the App Web Contents similar to a regular site's Site Contents.

However I have a trick to see the app web site contents by typing in the below URL as a suffix to your app web URL.
/_layouts/15/mcontent.aspx

Example: http://app-web-url/_layouts/15/mcontent.aspx

It lists all the available lists/libraries in the app web. But you will notice that the way the contents are listed is different from the regular Site Contents and by clicking on the list/library will redirects to list/library settings instead actual list. On the settings page you see the List Name which redirects to the actual list content.

Hope this post is helpful...

Create Folder in SharePoint using REST

Here is the quick code snippet to create a folder in a Library or List using SharePoint REST.

var docLibraryName = "DocLibrary";
var folderName = "FolderTest";
var appWebUrl = "http://weburl";

var folderRelativePath = ''; //Populate with the path after folder creation to add files to folder
var folder = CreateFolder(appWebUrl, docLibraryName, folderName);
if (folder && folder.statusText && folder.statusText == 'Created') {
    if (folder.responseJSON && folder.responseJSON.d) {
        folderRelativePath = folder.responseJSON.d.ServerRelativeUrl;
    }
}

////Method to create a folder and returns folder object with metadata
CreateFolder = function (url, libraryname, foldername) {
    var folderRelPath = libraryname + '/' + foldername;
    var requestUri = url + "/_api/web/folders";
    var data = $.ajax({
        url: requestUri,
        type: "POST",
        async: false,
        data: JSON.stringify({ '__metadata': { 'type': 'SP.Folder' }, 'ServerRelativeUrl': folderRelPath }),
        headers: {
            "accept": "application/json; odata=verbose",
            "content-type": "application/json; odata=verbose",
            "X-RequestDigest": $("#__REQUESTDIGEST").val()
        },
        success: function (data) {
            alert('Folder created successfully.');
            return data;
        },
        error: function (error) {
            alert('Folder creation failed!');
            //alert(JSON.stringify(error));
            return data;
        }
    });
    return data;
}

Reference:
SharePoint REST Create Folder in Library
Creating Folder in Library using REST
REST Create Folder in SharePoint Library

SharePoint Custom ULS Logging

Here is a working code snippet (C# class) to write custom errors or logs to ULS log.

using Microsoft.SharePoint;
using Microsoft.SharePoint.Administration;
using System.Collections.Generic;

namespace CustomLogging
{
    class LoggingService : SPDiagnosticsServiceBase
    {
        public static string diagnostcAreaName = "CustomLogging";
        public static string errorPrefix = "CustomLogging: ";

        private LoggingService()
            : base("CustomLogging Logging Service", SPFarm.Local)
        {
        }

        protected override IEnumerable<SPDiagnosticsArea> ProvideAreas()
        {
            List<SPDiagnosticsArea> areas = new List<SPDiagnosticsArea>
            {
                new SPDiagnosticsArea(diagnostcAreaName, new List<SPDiagnosticsCategory>
                {
                    new SPDiagnosticsCategory("CustomLogging", TraceSeverity.Unexpected, EventSeverity.Error)
                })
            };

            return areas;
        }

        public static void LogError(string message, EventSeverity eventSeverity)
        {
            SPSecurity.RunWithElevatedPrivileges(delegate ()
            {
                SPDiagnosticsService diagnosticService = SPDiagnosticsService.Local;
                diagnosticService.WriteTrace(0, new SPDiagnosticsCategory(diagnostcAreaName, TraceSeverity.Monitorable, eventSeverity),
                   TraceSeverity.Monitorable, errorPrefix + "{0}", new object[] { message });
            });

        }
    }
}

An entry to ULS logs can be written using the below snippet with make use of the above class.

try
{
    //Business logic
}
catch (Exception ex)
{
    LoggingService.LogError(ex.Message + " " + ex.StackTrace + "\r" + ex.Source, (EventSeverity)EventSeverity.Information);
}

SharePoint Cross Site Lookup Field

Can we create a cross site lookup field?
Yes of course, it can be. Thought it is not possible OTB, a simple trick will do this.

Scenario: Creating a cross site lookup field between the two peer web sites or sub web sites under a same site collection.
Example: Create a lookup field between two sites http:/sitecollection/webA & http://sitecollection/webB

The trick is just to set the lookup field webId with the target list webId.
Code snippet to create cross site lookup field programatically:

private bool CreateCrossSiteLookupField(SPWeb sourceWeb, SPWeb targetWeb, string sourceListTitle, string targetListtitle, string lookUpFieldName, string lookupValueColumn, bool isRequiredField)
{
    ////Get the source and target lists 
    SPList sourceList = sourceWeb.Lists.TryGetList(sourceListTitle);
    SPList targetList = targetWeb.Lists.TryGetList(targetListtitle);

    if (null != sourceList && null != targetList)
    {
        ////Add a lookup field to source list with target list as lookup list
        sourceList.Fields.AddLookup(lookUpFieldName, targetList.ID, isRequiredField);

        ////Get the created lookup field from source list 
        SPFieldLookup lookupField = (SPFieldLookup)sourceList.Fields[lookUpFieldName];

        ////Set the lookup field's webID with target list webId
        lookupField.LookupWebId = targetList.ParentWeb.ID;

        ////Set the lookup field's display field 
        lookupField.LookupField = targetList.Fields[lookupValueColumn].InternalName;

        ////Finally update the lookup field
        lookupField.Update();
    }
    return true;
}

Code snippet to create cross site lookup field with PowerShell:

Add-PSSnapIn "Microsoft.SharePoint.Powershell"

#Get the webs and lists
$webA = Get-SPWeb http://siteurl/webA/
$webB = Get-SPWeb http://siteurl/webB/
$sourceList = $webA.Lists.item("SourceList")
$targetList = $webB.Lists.item("TargetList")

#Add a lookup field to source list with target list as lookup list
$sourceList.fields.AddLookup("LookupFieldName", $targetList.id, "true")

#Get the created lookup field from source list
$lookupField = $sourceList.Fields["LookupFieldName"]

#Set the lookup field's webID with target list webId
$lookupField.LookupWebId = $targetList.ParentWeb.ID

#Set the lookup field's display field
$lookupField.LookupField = $targetList.Fields["Title"].InternalName
$lookupField.Update();

How to Get Outgoing E-Mail Settings Programatically

Sometimes it might be needed to get the Web Application outgoing emails settings programatically.
The below code snippet gives all the settings including Outbound SMTP server, From address, Reply-to address and Character set information.

using (SPSite site = new SPSite("http://siteurl"))
{
    SPWebApplication webApp = site.WebApplication;
    string outboundSMTPServer = webApp.OutboundMailServiceInstance.Parent.Name;
    string fromAddress = webApp.OutboundMailSenderAddress;
    string replyToAddress = webApp.OutboundMailReplyToAddress;
    int characterSet = webApp.OutboundMailCodePage;
}

Web application outgoing email settings can also be updated programatically as below.

using (SPSite site = new SPSite("http://siteurl"))
{
    string outboundSMTPServer = "Outbound SMTP server";
    string fromAddress = "From address";
    string replyToAddress = "Reply-to address";
    int characterSet = 65001; //Character set code

    SPWebApplication webApp = site.WebApplication;
    webApp.UpdateMailSettings(outboundSMTPServer,fromAddress,replyToAddress,characterSet);
}

Similarly we can get & set the Global outgoing email settings as below.
GET:

var globalAdmin = SPAdministrationWebApplication.Local;
var outboundSMTPServer = globalAdmin.OutboundMailServiceInstance.Parent.Name;
var fromAddress = globalAdmin.OutboundMailSenderAddress;
var replyToAddress = globalAdmin.OutboundMailReplyToAddress;
var characterSet = globalAdmin.OutboundMailCodePage;

SET:

string outboundSMTPServer = "Outbound SMTP server";
string fromAddress = "From address";
string replyToAddress = "Reply-to address";
int characterSet = 65001; //Character set code
var globalAdmin = SPAdministrationWebApplication.Local;
globalAdmin.UpdateMailSettings(outboundSMTPServer, fromAddress, replyToAddress, characterSet); 

SharePoint AutoComplete Lookup Field with JQuery

Created a Custom SharePoint Lookup field that offers new functionalities to default SharePoint lookup field by allowing Auto Complete or Type Ahead search functionality with Contains CAML query.

Below is a few of the features offered by AutoComplete Lookup field over standard SharePoint Lookup field:

• Auto Complete or Type Ahead lookup search (queries after each typing)
• OTB SharePoint Lookup Dropdown look and feel for the results 
• Proper validations
• Searches the lookup keyword with Contains CAML query
• Configurable for No.of results to be displayed
• Configurable for No.of characters to start the auto complete search

Limitations:

• It cannot be multi-valuated
• Only one AutoComplete Lookup field is allowed per list
• The target lookup field is frozen and always the Title field

The project is packaged as a Windows installer using the SharePoint Solution installer; to install, simply run setup.exe. The software is available on CodePlex here.

Please do let me know if you find any issues or bugs or useful enhancement that could be added.

SharePoint ListItem Update vs SystemUpdate vs UpdateOverwriteVersion

Here is a simple table format to explain the differences among Update vs SystemUpdate vs UpdateOverwriteVersion vs SystemUpdate(true). 

This information is pretty much useful to look at the differences between the following SPListItem methods when working with event receivers or workflows.

	Update()	SystemUpdate()	SystemUpdate(true)	UpdateOverwriteVersion()
Updates the item in the database	ü	ü	ü	ü
Creates a new version	ü	û	ü	û
Updates the Modified and Modified By values	ü	û	û	ü

How to update Modified By field in a SharePoint list item programatically

While adding/updating a list item using SPSecurity.RunWithElevatedPrivileges with administrator privileges, Created By / Modified By fields are set to System Account as the piece of code is executed with Application Pool account context.

But in an ideal case Created By / Modified By fields should have the original user who actually did the modification. In order to achieve this Created By / Modified By fields needs to be updated at the time of inserting / updating list item.

The catchy point here is to get the Current User out of the SPSecurity.RunWithElevatedPrivileges scope because within the scope it is always System Account as mentioned.

The below code snippet works as as explained above:

////Get the current user out of the SPSecurity.RunWithElevatedPrivileges scope
SPUser currentUser = SPContext.Current.Web.CurrentUser;

SPSecurity.RunWithElevatedPrivileges(delegate()
{
    using (SPSite newSite = new SPSite("http://siteurl"))
    {
        using (SPWeb newWeb = newSite.OpenWeb())
        {
            SPList list = newWeb.Lists.TryGetList("List Title");
            if (null != list)
            {
                bool isNewItem = true; //Adding or Updating item
                SPListItem item = list.GetItemById(1);
                if (isNewItem)
                {
                    item["Author"] = currentUser;
                }
                item["Editor"] = currentUser;

                item.Update();
            }
        }
    }
});

Reference:
How to update Modified By field programatically
How to update Created By field programatically
SharePoint List Item update Modified By field programatically
SharePoint List Item update Created By field programatically

How to Check Group Exists in SharePoint Programatically

I was trying to check if specific group exists in SharePoint web. I couldn't find any OTB API method to achieve this.
Hence I am using the below LINQ statement to check whether group exists in a web.

string groupName = "MyGroupName";
SPWeb web = SPContext.Current.Web;
 //Check if group exists in the web
 if (web.Groups.OfType<SPGroup>().Count(g=>g.Name.Equals(groupName, StringComparison.InvariantCultureIgnoreCase))>0)
 {
     //Get the SPGroup by group name if exists
     SPGroup group = web.Groups[groupName];
 }

Access Denied within SPSecurity.RunWithElevatedPrivileges

I never thought that SPSecurity.RunWithElevatedPrivileges gives an error "Access Denied". But yes, i see it in my below scenario.

I was doing an operation within an item event receiver which required higher level of access to update the web level information. Since this was to be executed irrespective of the access of the user logged in, i had the code to be executed within the SPSecurity.RunWithElevatedPrivileges. Unexpectedly the code was failing and throwing an error "Access Denied".

The below code executes well and fine for the users who has Full Control on a web but gives a "Access Denied' error for contributors or readers though the code is wrapped in SPSecurity.RunWithElevatedPrivileges.

public override void ItemCheckedIn(SPItemEventProperties properties)
{
            base.ItemCheckedIn(properties);
            SPSecurity.RunWithElevatedPrivileges(delegate()
            {
                         SPWeb web = properties.Web;
                         var listItem = properties.ListItem;
                          if (!listItem.Title.Equals(web.Title))
                          {
                                    web.AllowUnsafeUpdates = true;
                                    web.Title = listItem.Title;
                                    web.Update();
                                    web.AllowUnsafeUpdates = false;
                           }
             }
}

In the above code web.Update() throws an exception "Access Denied" Though the code is executing under RunWithElevatedPrivileges. Because the code doesn't really execute under elevated privileges as the respective object SPWeb was not created within the SPSecurity.RunWithElevatedPrivileges but it is retrieved through the receiver context properties.Web, which is created before elevated privileges. Hence the elevated privileges cannot be applied to that object.

The solution for this problem is very simple. Create the objects which are being used to perform some operations with in the SPSecurity.RunWithElevatedPrivileges.

public override void ItemCheckedIn(SPItemEventProperties properties)
{
          base.ItemCheckedIn(properties);
          SPSecurity.RunWithElevatedPrivileges(delegate()
          {                 
                 var listItem = properties.ListItem;
                 using (SPSite site = new SPSite(properties.Site.ID))
                 {
                        using (SPWeb web = site.OpenWeb(properties.Web.ID))
                        {     
                               if (!listItem.Title.Equals(web.Title))
                              {
                                    web.AllowUnsafeUpdates = true;
                                    web.Title = listItem.Title;
                                    web.Update();
                                    web.AllowUnsafeUpdates = false;
                              }
                        }
                 }
           }
}

In this case created a SPWeb object with in elevated previliges though it is available as properties.Web.

How to Add User to Default SharePoint Groups Programatically

As every SharePoint developer or user know that when a new Site is created, Obviously 3 commonly used site specific groups will be created automatically along with some general groups.
<Site Name> Owners
<Site Name> Members
<Site Name> Visitors

To add an user to any of the above three groups of a site, we have a API method to get the groups associated with that site, programatically.

using (SPSite site = new SPSite("http://siteurl"))
{
    using (SPWeb web = site.RootWeb)
    {
        ////Get the site default groups
        SPGroup owernsGroup = web.AssociatedOwnerGroup;
        SPGroup membersGroup = web.AssociatedMemberGroup;
        SPGroup visitorsGroup = web.AssociatedVisitorGroup;

        ////Add user to groups
        SPUser user = web.EnsureUser("login");
        if (null != user)
        {
            owernsGroup.AddUser(user);
            membersGroup.AddUser(user);
            visitorsGroup.AddUser(user);
        }
    }
}

Also we can add user to other default groups like Approvers, Designers and Viewers etc., But there is no API property for web to get these groups. So we can get the group by Name.

if (web.GroupExists("Approvers"))
{
    ////Get approvers group
    SPGroup approversGroup = web.Groups["Approvers"];            
    if (null != approversGroup)
    {
        ////Add user to group
        SPUser user = web.EnsureUser("login");
        approversGroup.AddUser(user);
    }
}

Check User exists in SharePoint Group

I was looking for direct API method to check whether specified user exists in SharePoint group. Unfortunately there is no direct API check.

I found below single statement is efficient for this check. I made it a generic for re-usability.

SPGroup spGroup = web.Groups["Group Name"];
if (null != spGroup)
{
  SPUser spUser = web.EnsureUser("Login Account");
  if (null != spUser)
  {
    bool userExsists = spUser.Groups.Cast<SPGroup>().Any(g => g.Name.ToLower() == spGroup.Name.ToLower());
     if (!userExsists)
     {
        spGroup.AddUser(spUser);
     }
  }
}