Optimizing Code Reusability For SharePoint Using LINQ and the MVP Design Pattern

Houston Tech Fest 2014

Introduction – Ted Wagner

BS in Game Software DevelopmentSharePoint SME for over 3 Years.Conducted multiple training sessions for SharePoint 2010 and 2013.Worked for Sparkhound over a year.

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Overview

Review the MVP patternSetting up models to promote encapsulation and testingSetting up Presenters and Views for separation of functionality to promote testing

Outcome

Reusable SharePoint solutions to be used between various applications and SharePoint projects.

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What is MVP?

A design pattern used to separate functionality from controls to maximize the amount of code that can be tested automatically.Separation of the logic of events and the updates made to the application data.Uses an Interface to reference the view instead of the view classMany different variations

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What is MVP?

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Microsoft Corporation. (2014). The Model-View-Presenter (MVP) Pattern. Retrieved September 3, 2014, from Microsoft Developer Network: http://msdn.microsoft.com/en-us/library/ff649571.aspx

MVP image (Microsoft Corporation, 2014)

Supervising Presenter

Why use MVP with SharePoint?

MVC is technically “not supported”Designs are usually scoped to one view – Web PartsIncrease Unit TestingEncapsulation of SharePoint Methods and Assemblies

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Model

Data Model1. Data Model

1. Representation of columns within a List or Library

2. Business Model1. Represented as an interface2. Data access object used to query database

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View

Class Containing visual controlsHandles eventsContains Page Events, JavaScript, CSS, JQuery and any other Front-End functionalityViews do not have knowledge of the modelAn interface is designated to the view for updating the view state when the model is updated. 1

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Presenter

The class that combines the view to the data models.Updates the view.One presenter per viewEasily attach to Unit testing projects for automation.

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LINQ to SharePoint

Utilize LINQ to easily query SharePoint ListsProvides quick way to cast objects to generics for encapsulationQuickly generate models representing SharePoint Lists using SPMetal

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Setting up Solution

Create a Class Library Project for storing ModelsCreate Project for SharePoint SolutionsSign keyAdd assembly to package

Package->Advanced->Add

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Setting up your Models

• Create a separate project for you models only

• Setup your data models• Setup Data Access Objects and business

model interfaces

Best Practices• Keep all SharePoint references in the

models• Keep error handling to a minimum in the

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Data Model Example

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public class CustomerModel { public string CustId { get; set; } public string FirstName { get; set; } public string LastName { get; set; } public string Address { get; set; } public string City { get; set; } public string State { get; set; } public string Zip { get; set; } public bool Vendor { get; set; } }

Generate DataContext With SPMetal

• SPMetal – located in the BIN folder in Hive• Create Environment Variable referencing

SPMetal in hive folder• System Properties -> Advanced Settings ->

Advanced• Create Folder for storing DataContext Files

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C:\SPMetal /web:http://sparkhound.ted.local /code:CustomerDataContext.cs

Using DataContext ModelUsing Preconfigured data models from SPMetal

ProsGenerates exact column namesNo need to create data models

ConsCannot keep SharePoint functionality within the modelHard to find and update models

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Example

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public List<CustomerItem> GetCustomers() {

using (TechfestdatacontextDataContext dc = new TechfestdatacontextDataContext(SPContext.Current.Site.Url)) { EntityList<CustomerItem> customers = dc.GetList<CustomerItem>("Customer");

var allCustomers = from c in customers select c;

return allCustomers.ToList<CustomerItem>(); } }

Using Custom Data ModelDesigning your own Data Model

ProsFlexibility to control what data is passedControl namesEncapsulate SharePoint references

ConsMust create each data model manually

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Example

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using(TechfestdatacontextDataContext dc = new TechfestdatacontextDataContext(SPContext.Current.Site.Url)) { EntityList<RegisterItem> register = dc.GetList<RegisterItem>("Register");

var customerDetails = from r in register where r.CustID == CustId select new RegisterModel { CustId = r.CustID, Credit = Convert.ToDouble(r.Credit), Debit = Convert.ToDouble(r.Debit), Date = Convert.ToDateTime(r.Date), RegisterId = r.Title };

return customerDetails.ToList<RegisterModel>(); }

Setting up the presenter

The presenter will reference the view through an interfaceOverload the constructor to pass the viewAll functionality is handled by the presenter

Best PracticesUse bool functions to catch errors. Return false for errors to keep other functionality from continuing.

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Example

Constructor accepting view and assigning it to a variable

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public CustomerInfoPresenter(ICustomerInfoView View) { view = View; }

Example

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public bool GetCustomerInfo() { try { CustomerBusinessObject model = new CustomerBusinessObject(); view.GetCustomers = model.GetCustomers();

return true; } catch (Exception ex) { view.ErrorMsg = "Error Getting Customer Info: " + ex.Message; return false; } }

Setting up the view

Views use properties to assign values and populate controls Minimum functionality in viewsRepresent data in an interface to pass data

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public interface ICustomerInfoView { List<CustomerItem> GetCustomers {get; set;} List<RegisterModel> CustomerData {get; set;} string ErrorMsg { get; set; } }

Example

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public List<CustomerItem> GetCustomers { get { return CustomerDDL.DataSource as List<CustomerItem>; } set { CustomerDDL.DataTextField = "LastName"; CustomerDDL.DataValueField = "Title"; CustomerDDL.DataSource = value; CustomerDDL.DataBind();

CustomerDDL.Items.Insert(0, "Please select a customer..."); } }

Example – Page Load

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protected void Page_Load(object sender, EventArgs e) { if (!Page.IsPostBack) { CustomerInfoPresenter presenter = new CustomerInfoPresenter(this);

presenter.GetCustomerInfo(); } }

Pros/ConsPros

EncapsulationEasily give code to other developers

Reusability with other projects and applicationsAbility to manipulate and bind data after query

ConsIssues with cross site collection queriesLINQ is not Thread SafeSlower than CAMLExtra coding overhead

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Overcoming cross site collection queries

1. Extend DataContext Model to include a new constructor that accepts different site collections.

2. Change the Current Context to the site collection being queried.

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Overcoming cross site collection queries

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var CurrentContext = HttpContext.Current;(using SPSite site = new SPSite(SiteCollectionUrl)){

(using(SPWeb web = site.OpenWeb()){

HttpRequest request = new HttpRequest(“”, SiteCollectionURL, “”);HttpContext.Current = new HttpContext(request, new HttpRespone(new StringWriter()));

//Perform Linq Query}

}

HttpContext.Current = CurrentContext;

Questions

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Contact Info

Ted WagnerTed.wagner@sparkhound.com

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Works CitedMicrosoft Corporation. (2014). The Model-View-Presenter (MVP) Pattern. Retrieved September 3, 2014, from Microsoft Developer Network: http://msdn.microsoft.com/en-us/library/ff649571.aspx

 

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