theKindOfMe

July 1, 2009

Using Custom T4 templates To Generate Better Controllers in ASP MVC

Filed under: Uncategorized — Tags: , , , , — yasi8h @ 7:52 am

While working on this asp.net mvc project at work i couldn’t help notice that there are lots of code that is getting copy-pasted from one controller to the other, when i am adding a new controller. now as you know mvc fm comes with a set of T4 templates that lets you add views and controllers in such a way that some code in these views and controllers are generated for you. this is grate. but you can customize the original templates to your needs and make them generate more of the code for you. (please note that i am talking about controllers that are responsible for mostly CURD on a given single model.)

First of all you will need to identify what code gets repeated from controller to controller in your asp.net mvc project. and then you can get these stuff out in to a template and start working on it.

Locating the T4 Templates

you can find your original templates in [Visual Studio Install Directory]\Common7\IDE\ItemTemplates\[CSharp | VisualBasic]\Web\MVC\CodeTemplates\ and the you can copy them to your project folder. you can start editing these copies and they will be used when you invoke your templates(ex:- by clicking on the Add Controller sub menu within the IDE). for more info please refer to T4 Templates: A Quick-Start Guide for ASP.NET MVC Developers )

Customizing

In my case i wanted my controllers to have all the basic actions like List, Details, Create, Edit and my custom actions like Grid, GridData(take a look at A Grid with Ajax/Pagination/Sorting/Filtering on ASP.net MVC with ExtJS and Enitiy Framework).

i needed to get the type of the model that a given controller is associated with. and then i have to traverse it’s properties(through reflection…etc) and do some string manipulation to generate custom method signatures and custom anonymous types. i also wanted to filter the list of properties that will be used in these parameters and anon types.

Action method signatures

action method signatures can be different from controller to controller. as in…

//Different Properties, in different models
//
//Create action of a Product Controller
public ActionResult Create(string ID, string Name, string Description, string Price)
//
//Create action of a User Controller
public ActionResult Create(string ID, string Name, string Age)

//Different Primary Keys in different models
//
public ActionResult Details(int UID)
//
public ActionResult Details(int UID, int SiteUID)

Method calls to models

//Different Primary Keys
//
public ActionResult Details(int UID)
        {
            return View(Category.GetModelByPrimaryKey(new {UID}));
        }
//
public ActionResult Details(int UID, int SiteUID)
        {
            return View(Category.GetModelByPrimaryKey(new {UID, SiteUID}));
        }

//Different Properties for different models
//
public ActionResult Create(string ID, string Name)
        {
            Category.Create(new {ID,Name}, User.Identity.Name)
            return View();
        }
//
public ActionResult Create(string ID, string Name, int PropOne, string PropTwo)
        {
            Category.Create(new {ID,Name, PropOne, PropTwo}, User.Identity.Name)
            return View();
        }

But unlike in the view here in the controller you can’t just access the model’s type through MvcTextTemplateHost.ViewDataType. when you are generating a controller this property is null. so i thought of using reflection get the model for the current controller. you can use the ControllerRootName property of MvcTextTemplateHost(available through mvcHost variable in the default template) to get the model name(ex: ProductController would give Product).

<#
Type controllerType = Assembly.LoadFile("D:\\path\\to\\your\\model\\assemblys\\dll\\file.dll").GetType("Example.Models." + mvcHost.ControllerRootName);
#>

Following is the full source code of a generated controller and the modified template that was used to generate it. I have reused some methods like IsBindableType and GetEntityKeyProperties(i have modified this a bit) that can be found in some View templates in mvc framework. The generated controller can be used to do CURD operations on the model and provide a backend(providing data to the grid through json) for a ExtJS grid! 🙂 (A Grid with Ajax/Pagination/Sorting/Filtering on ASP.net MVC with ExtJS and Enitiy Framework)

Generated Controller

//
//A Generated Controller
//
using System;
using System.Collections;
using System.Web.Mvc;
using ExampleInc.Filters;
using ExampleInc.Lib.Helpers;
using ExampleInc.Models;
using ExampleInc.Models.UoW;

namespace ExampleInc.Controllers
{
	[Authorize]
    [NavigationFilter]
    public class ExampleModelController : Controller
    {
        //
        // GET: /ExampleModel/
        public ActionResult Index()
        {
            return RedirectToAction("List");
        }

        //
        // GET: /ExampleModel/Details/5
        public ActionResult Details(Int32 SiteUID,Int32 UID)
        {
            return View(ExampleModel.GetModelByPrimaryKey(new {SiteUID,UID}));
        }

        //
        // GET: /ExampleModel/Create
        public ActionResult Create()
        {
            return View();
        } 

        //
        // POST: /ExampleModel/Create
        [AcceptVerbs(HttpVerbs.Post)]
        public ActionResult Create(Int32 SiteUID ,Int32 UID ,String ID ,String Name ,Decimal Turnover ,String StreetAddress ,String City ,String PostalCode ,String Telephone1 ,String Telephone2 ,String Email ,String Fax ,String Notes ,String Capacity ,Int16 NumberOfMealsPerDay ,Decimal SellingPricePerMeal ,Decimal BudgetPricePerMeal ,String BestTimeToCall ,Byte TradingDaysPerWeek ,Byte TradingWeeksPerYear ,Boolean AccountActive ,Int32 PrimaryContact_SiteUID ,Int32 PrimaryContactUID ,DateTime LastCallStartTime ,Boolean IsProfileCall )
        {
            if (ViewData.ModelState.IsValid)
            {
                // Attempt to add the user

                if (ExampleModel.Create(new {SiteUID ,UID ,ID ,Name ,Turnover ,StreetAddress ,City ,PostalCode ,Telephone1 ,Telephone2 ,Email ,Fax ,Notes ,Capacity ,NumberOfMealsPerDay ,SellingPricePerMeal ,BudgetPricePerMeal ,BestTimeToCall ,TradingDaysPerWeek ,TradingWeeksPerYear ,AccountActive ,PrimaryContact_SiteUID ,PrimaryContactUID ,LastCallStartTime ,IsProfileCall }, User.Identity.Name))
                {
                    TempData["StatusBar"] += "ExampleModel '" + ID + "' successfully added.";
                    return RedirectToAction("List");
                }

                ModelState.AddModelError("_FORM", "Error");
            }

            // If we got this far, something failed, redisplay form
            return View();
        }

        //
        // GET: /ExampleModel/Edit/5
        public ActionResult Edit(Int32 SiteUID,Int32 UID)
        {
            return View(ExampleModel.GetModelByPrimaryKey(new {SiteUID,UID}));
        }

        //
        // POST: /ExampleModel/Edit/5
        [AcceptVerbs(HttpVerbs.Post)]
        public ActionResult Edit(Int32 SiteUID ,Int32 UID ,String ID ,String Name ,Decimal Turnover ,String StreetAddress ,String City ,String PostalCode ,String Telephone1 ,String Telephone2 ,String Email ,String Fax ,String Notes ,String Capacity ,Int16 NumberOfMealsPerDay ,Decimal SellingPricePerMeal ,Decimal BudgetPricePerMeal ,String BestTimeToCall ,Byte TradingDaysPerWeek ,Byte TradingWeeksPerYear ,Boolean AccountActive ,Int32 PrimaryContact_SiteUID ,Int32 PrimaryContactUID ,DateTime LastCallStartTime ,Boolean IsProfileCall )
        {
            if (ViewData.ModelState.IsValid)
            {
                if (ExampleModel.Update(new {SiteUID,UID}, new {SiteUID ,UID ,ID ,Name ,Turnover ,StreetAddress ,City ,PostalCode ,Telephone1 ,Telephone2 ,Email ,Fax ,Notes ,Capacity ,NumberOfMealsPerDay ,SellingPricePerMeal ,BudgetPricePerMeal ,BestTimeToCall ,TradingDaysPerWeek ,TradingWeeksPerYear ,AccountActive ,PrimaryContact_SiteUID ,PrimaryContactUID ,LastCallStartTime ,IsProfileCall }, User.Identity.Name))
                {
                    TempData["StatusBar"] += "ExampleModel '" + ID + "' successfully updated.";
                    return RedirectToAction("List");
                }

                ModelState.AddModelError("_FORM", "Error");
            }

            // If we got this far, something failed, redisplay form
            return View(ExampleModel.GetModelByPrimaryKey(new {SiteUID,UID}));
        }

        public ActionResult Delete(Int32 SiteUID,Int32 UID)
        {
            if (ExampleModel.Delete(new {SiteUID,UID}))
            {
                TempData["StatusBar"] += "ExampleModel successfully deleted.";
            }
            else
            {
                TempData["StatusBar"] += "ExampleModel delete operation failed!.";
            }
            return RedirectToAction("List");
        }

        public ViewResult List()
        {
            return View();
        }

        public ViewResult Grid(string RowClickEventHandlerFunctionName)
        {
            ViewData["RowClickEventHandlerFunctionName"] = RowClickEventHandlerFunctionName;
            return View();
        }

        public JsonResult GridData()
        {
            int totalOjectCount;
            var ExampleModelsList = EmExtJSGridFilterHelper.GetResults(Request, DataMan.ObjectContext.ExampleModel, out totalOjectCount);
            var list = new ArrayList();
            foreach (var ExampleModel in ExampleModelsList) //populate data containers with read data
            {
                list.Add(new
                             {
                                 ExampleModel.SiteUID ,ExampleModel.UID ,ExampleModel.ID ,ExampleModel.Name ,ExampleModel.Turnover ,ExampleModel.StreetAddress ,ExampleModel.City ,ExampleModel.PostalCode ,ExampleModel.Telephone1 ,ExampleModel.Telephone2 ,ExampleModel.Email ,ExampleModel.Fax ,ExampleModel.Notes ,ExampleModel.Capacity ,ExampleModel.NumberOfMealsPerDay ,ExampleModel.SellingPricePerMeal ,ExampleModel.BudgetPricePerMeal ,ExampleModel.BestTimeToCall ,ExampleModel.TradingDaysPerWeek ,ExampleModel.TradingWeeksPerYear ,ExampleModel.AccountActive ,ExampleModel.PrimaryContact_SiteUID ,ExampleModel.PrimaryContactUID ,ExampleModel.LastCallStartTime ,ExampleModel.IsProfileCall
                             });
            }
            return Json(new {dataitExampleInc = list.ToArray(), totalItExampleInc = totalOjectCount});
        }
    }
}

T4 Template used to Generate the Controller

<#@ template language="C#" HostSpecific="True" #>
<#@ output extension="cs" #>
<#@ assembly name="System.Data.Entity" #>
<#@ assembly name="System.Data.Linq" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ import namespace="System.Reflection" #>
<#@ import namespace="System.Data.Objects.DataClasses" #>
<#@ import namespace="System.Data.Linq.Mapping" #>
<#
MvcTextTemplateHost mvcHost = (MvcTextTemplateHost)(Host);
#>
<#
Type controllerType = Assembly.LoadFile("D:\\work_items\\ExampleInc\\ExampleInc-Alt-21\\ExampleInc.Models\\bin\\Debug\\ExampleInc.Models.dll").GetType("ExampleInc.Models." + mvcHost.ControllerRootName);

PropertyInfo&#91;&#93; piArray = controllerType.GetProperties(BindingFlags.Public|BindingFlags.Instance|BindingFlags.DeclaredOnly);

string actionMethodParamerters = "", anonTypePropValString = "", gridDataAnonTypePropValString = "";
foreach (PropertyInfo pi in piArray)
		{
			Type currentPropertyType = GetUnderlyingType(pi.PropertyType);

			if(IsBindableType(currentPropertyType) && IsNeededProp(pi.Name))
			{
				actionMethodParamerters += currentPropertyType.Name + " " + pi.Name + " ,";
				anonTypePropValString += pi.Name + " ,";
				gridDataAnonTypePropValString += mvcHost.ControllerRootName.ToLower() + "." + pi.Name + " ,";
			}
		}
actionMethodParamerters = actionMethodParamerters.Remove(actionMethodParamerters.Length - 1); //remove the last extra ","
anonTypePropValString = anonTypePropValString.Remove(anonTypePropValString.Length - 1); //remove the last extra ","
gridDataAnonTypePropValString = gridDataAnonTypePropValString.Remove(gridDataAnonTypePropValString.Length - 1); //remove the last extra ","
#>
using System;
using System.Collections;
using System.Web.Mvc;
using ExampleInc.Filters;
using ExampleInc.Lib.Helpers;
using ExampleInc.Models;
using ExampleInc.Models.UoW;

namespace <#= mvcHost.Namespace #>
{
	[Authorize]
    [NavigationFilter]
    public class <#= mvcHost.ControllerName #> : Controller
    {
        //
        // GET: /<#= mvcHost.ControllerRootName #>/
        public ActionResult Index()
        {
            return RedirectToAction("List");
        }

<#
if(mvcHost.AddActionMethods) {
#>
        //
        // GET: /<#= mvcHost.ControllerRootName #>/Details/5
        public ActionResult Details(<#= GetMethodParamertersString(controllerType) #>)
        {
            return View(<#= mvcHost.ControllerRootName #>.GetModelByPrimaryKey(new {<#= GetDataAnonTypePropValString(controllerType) #>}));
        }

        //
        // GET: /<#= mvcHost.ControllerRootName #>/Create
        public ActionResult Create()
        {
            return View();
        } 

        //
        // POST: /<#= mvcHost.ControllerRootName #>/Create
        [AcceptVerbs(HttpVerbs.Post)]
        public ActionResult Create(<#= actionMethodParamerters #>)
        {
            if (ViewData.ModelState.IsValid)
            {
                // Attempt to add the user

                if (<#= mvcHost.ControllerRootName #>.Create(new {<#= anonTypePropValString #>}, User.Identity.Name))
                {
                    TempData["StatusBar"] += "<#= mvcHost.ControllerRootName #> '" + ID + "' successfully added.";
                    return RedirectToAction("List");
                }

                ModelState.AddModelError("_FORM", "Error");
            }

            // If we got this far, something failed, redisplay form
            return View();
        }

        //
        // GET: /<#= mvcHost.ControllerRootName #>/Edit/5
        public ActionResult Edit(<#= GetMethodParamertersString(controllerType) #>)
        {
            return View(<#= mvcHost.ControllerRootName #>.GetModelByPrimaryKey(new {<#= GetDataAnonTypePropValString(controllerType) #>}));
        }

        //
        // POST: /<#= mvcHost.ControllerRootName #>/Edit/5
        [AcceptVerbs(HttpVerbs.Post)]
        public ActionResult Edit(<#= actionMethodParamerters #>)
        {
            if (ViewData.ModelState.IsValid)
            {
                if (<#= mvcHost.ControllerRootName #>.Update(new {<#= GetDataAnonTypePropValString(controllerType) #>}, new {<#= anonTypePropValString #>}, User.Identity.Name))
                {
                    TempData["StatusBar"] += "<#= mvcHost.ControllerRootName #> '" + ID + "' successfully updated.";
                    return RedirectToAction("List");
                }

                ModelState.AddModelError("_FORM", "Error");
            }

            // If we got this far, something failed, redisplay form
            return View(<#= mvcHost.ControllerRootName #>.GetModelByPrimaryKey(new {<#= GetDataAnonTypePropValString(controllerType) #>}));
        }

        public ActionResult Delete(<#= GetMethodParamertersString(controllerType) #>)
        {
            if (<#= mvcHost.ControllerRootName #>.Delete(new {<#= GetDataAnonTypePropValString(controllerType) #>}))
            {
                TempData["StatusBar"] += "<#= mvcHost.ControllerRootName #> successfully deleted.";
            }
            else
            {
                TempData["StatusBar"] += "<#= mvcHost.ControllerRootName #> delete operation failed!.";
            }
            return RedirectToAction("List");
        }

        public ViewResult List()
        {
            return View();
        }

        public ViewResult Grid(string RowClickEventHandlerFunctionName)
        {
            ViewData["RowClickEventHandlerFunctionName"] = RowClickEventHandlerFunctionName;
            return View();
        }

        public JsonResult GridData()
        {
            int totalOjectCount;
            var <#= mvcHost.ControllerRootName.ToLower() #>sList = EmExtJSGridFilterHelper.GetResults(Request, DataMan.ObjectContext.<#= mvcHost.ControllerRootName #>, out totalOjectCount);
            var list = new ArrayList();
            foreach (var <#= mvcHost.ControllerRootName.ToLower() #> in <#= mvcHost.ControllerRootName.ToLower() #>sList) //populate data containers with read data
            {
                list.Add(new
                             {
                                 <#= gridDataAnonTypePropValString #>
                             });
            }
            return Json(new {dataitems = list.ToArray(), totalItems = totalOjectCount});
        }
<#
}
#>
    }
}
<#+
public static List<PropertyInfo> GetEntityKeyProperties(Type type)
{
	List<PropertyInfo> keyProperties = new List<PropertyInfo>();

	PropertyInfo[] properties = type.GetProperties();

	foreach (PropertyInfo pi in properties)
	{
		System.Object[] attributes = pi.GetCustomAttributes(true);

		foreach (object attribute in attributes)
		{
			if (attribute is EdmScalarPropertyAttribute)
			{
				if ((attribute as EdmScalarPropertyAttribute).EntityKeyProperty == true)
				{
					keyProperties.Add(pi);
				}
			} else if(attribute is ColumnAttribute) {
				if ((attribute as ColumnAttribute).IsPrimaryKey == true)
				{
					keyProperties.Add(pi);
				}
			}
		}
	}

	return keyProperties;
}

public bool IsBindableType(Type type)
{
	bool isBindable = false;

	if (type.IsPrimitive || type.Equals(typeof(string)) || type.Equals(typeof(DateTime)) || type.Equals(typeof(decimal)) || type.Equals(typeof(Guid)) || type.Equals(typeof(DateTimeOffset)) || type.Equals(typeof(TimeSpan)))
	{
		isBindable = true;
	}

	return isBindable;
}

public bool IsNeededProp(string propName)
        {
            switch (propName)
            {
                case "CreationDate":
                case "LastModifiedDate":
                case "LastModifiedBy":
                case "EffectiveDate":
                case "ExpiryDate":
                case "ServerEntryDate":
                    return false;
            }
            return true;
        }

public string GetMethodParamertersString(Type viewDataType)
        {
			List<PropertyInfo> primaryKeys = GetEntityKeyProperties(viewDataType);

			if(primaryKeys.Count > 0) {
				string result = "";
				foreach(PropertyInfo pk in primaryKeys)
				{
					result += String.Format("{0} {1},", GetUnderlyingType(pk.PropertyType).Name , pk.Name);
				}

				return result.Remove(result.Length - 1); //remove the last extra ","
			} else {
				return "UID=Model.PrimaryKey";
			}
        }

public string GetDataAnonTypePropValString(Type viewDataType)
        {
			List<PropertyInfo> primaryKeys = GetEntityKeyProperties(viewDataType);

			if(primaryKeys.Count > 0) {
				string result = "";
				foreach(PropertyInfo pk in primaryKeys)
				{
					result += String.Format("{0},", pk.Name);
				}

				return result.Remove(result.Length - 1); //remove the last extra ","
			} else {
				return "UID=Model.PrimaryKey";
			}
        }

public Type GetUnderlyingType(Type type)
{
	Type currentPropertyType = type;
			Type currentUnderlyingType = System.Nullable.GetUnderlyingType(currentPropertyType);
			if(currentUnderlyingType != null) {
				currentPropertyType = currentUnderlyingType;
			}

			return currentPropertyType;
}
#>

hope this will help someone/myself in the feuture 🙂

February 5, 2009

A Grid with Ajax/Pagination/Sorting/Filtering on ASP.net MVC with ExtJS and Enitiy Framework

Filed under: Uncategorized — Tags: , , , , , , , — yasi8h @ 9:18 am

I am new to all these JS libraries like jQuery and ExtJS(there are many more out there…). when i got started with asp.net mvc i looked in to jQuery. and i was absolutely amazed with all the functionality it offered with very simple and neat syntax! a while ago i did a post on “Ajax Enabling MVCContrib Grid’s Pagination with jQuery”. In which i added AJAX/pagination support to MVCContrib’s Grid. but with time i needed more and more features from the grid. like sorting and filtering(through AJAX of course). then i came across the wonderful JS library called ExtJS. it have grate UI components done and ready to be used. i love all ExtJS stuff that is related to UI. and their components seems to be very extensible as well.

Ext JS Overview

Ext JS is a cross-browser JavaScript library for building rich Internet applications. It includes:

  • High performance, customizable UI widgets
  • Well designed and extensible Component model
  • An intuitive, easy to use API
  • Commercial and Open Source licenses available

i liked there Grid and it had all the features i needed. so i decided to go ahead with it.

extjs_grid_screenshot

the main points i had to look at:

  • including a ExtJS distribution with my asp.net mvc project which is already using jQuery
  • inserting the relevant JS to render the grid in my views
  • creating the necessary controller actions to support the grid’s actions(get data/sort/filter data…etc)

Including a ExtJS distribution

ExtJS JS library can use other libraries(such as jQuery…) as its base library. so been a fan of jQuery, i choose to build a custom version of ExtJS which uses jQuery as its base.  this version of the library includes the jQuery adapter within it self. but you still need to include the jQuery library by your self. it is NOT included in the custom version that you built for your self.  so in your site.master(you can put these where ever you like, not necessary in the site.master. just make sure these are included where ever you use them) you have to include the libraries in the following order: include jQuery first, then include any jQuery plugins you use and finally include ExtJS(any of your custom JS files should be included afterward).

now you are done including the JS libraries necessary . but ExtJS’s UI components need a few more things to be included in your site.master for them to work correctly. you need to include the necessary style sheets/images used by ExtJS components. to get these download ExtJS SDK. this includes all the style sheets and the images among other things. you will need to include the necessary plugins as well.

  • ext-2.2resourcescssext-all.css
  • ext-2.2resourcesimages – images used by ExtJS components
  • all JS files under ext-2.2examplesgrid-filteringgrid – includes necessary plugins needed for the grid filtering functionality

now you are ready to roll. note that we can use what ever jQuery we want when we are working with extjs components. and as we are using the jQuery core(and also because we are already using jQuery in out mvc project) the size of the ExtJS library is much lower.

Rendering the grid

looking at the samples(look under ext-2.2examplesgrid-filtering) included in the extjs sdk. its not that hard to figure out how to render the grid using javascript. the extjs API reference would be helpful as well.

i ran across a bug in the GridView component when i tried to use disable ‘autoHeight’ ‘feature’ of the grid. how ever there was a fix available for it in the the extjs forums.  following is the JS code that i used in my view(in which the grid resides). i just included them in a script tag within the view. but the best way to use them would be to extract them in to some helper methods and then using the helpers.

some notes about ExtJs grids

  • a grid is ‘bound’ to a data store.
  • when rendering a grid you will have to create a data record, column modal and a data reader(JsonReader in this case).
  • column modal – how the columns are structured
  • data record – how a data record(or a person object, in the context of this example) is structured. what fields does it contain…etc
  • data reader – where to get/ how to read data
  • filters and paging is connected to the grid in a ‘pluggable’ manner

        //Sugguested Fix for the bug: "Grid autoHeight disables horizontal scrolling too"
        Ext.override(Ext.grid.GridView, {
            layout: function() {
                if (!this.mainBody) {
                    return;
                }
                var g = this.grid;
                var c = g.getGridEl(), cm = this.cm,
                expandCol = g.autoExpandColumn,
                gv = this;
                var csize = c.getSize(true);
                var vw = csize.width;
                if (vw < 20 || csize.height < 20) {
                    return;
                }
                if (g.autoHeight) {
                    csize.height = this.mainHd.getHeight() + this.mainBody.getHeight();
                    if (!this.forceFit) {
                        csize.height += this.scrollOffset;
                    }
                }
                this.el.setSize(csize.width, csize.height);
                var hdHeight = this.mainHd.getHeight();
                var vh = csize.height - (hdHeight);
                this.scroller.setSize(vw, vh);
                if (this.innerHd) {
                    this.innerHd.style.width = (vw) + 'px';
                }
                if (this.forceFit) {
                    if (this.lastViewWidth != vw) {
                        this.fitColumns(false, false);
                        this.lastViewWidth = vw;
                    }
                } else {
                    this.autoExpand();
                }
                this.onLayout(vw, vh);
            }
        });
        //end bug fix here
        //////////////////

        Ext.onReady(function() {
            Ext.QuickTips.init(); //for enabling tool tips

            Ext.menu.RangeMenu.prototype.icons = {
                gt: '/Scripts/extjs/plugins/grid-filter/img/greater_then.png',
                lt: '/Scripts/extjs/plugins/grid-filter/img/less_then.png',
                eq: '/Scripts/extjs/plugins/grid-filter/img/equals.png'
            };
            Ext.grid.filter.StringFilter.prototype.icon = '/Scripts/extjs/plugins/grid-filter/img/find.png';

            createAndShowGrid();
        });

        function createAndShowGrid() {

            order = Ext.data.Record.create(&#91;
	        { name: 'Id' },
	        { name: 'FirstName' },
	        { name: 'Email' }
        &#93;);

            orderReader = new Ext.data.JsonReader({
                root: 'dataitems',
                totalProperty: 'totalItems' //number of total records
            },
		    order
	    );
            //data store creation
            ds = new Ext.data.Store({
                proxy: new Ext.data.HttpProxy({
                    url: '/Person/ListJson'
                }),
                reader: orderReader,
                sortInfo: { field: 'Id', direction: "ASC" },
                remoteSort: true
            });

            columnModel = new Ext.grid.ColumnModel(&#91;{
                header: 'Person Id',
                dataIndex: 'Id'
            }, {
                header: 'Person Name',
                dataIndex: 'FirstName'
            }, {
                header: 'Person Email',
                dataIndex: 'Email'
            }
	    &#93;);

            columnModel.defaultSortable = true;

            var filters = new Ext.grid.GridFilters({
                filters: &#91;
	                { type: 'string', dataIndex: 'Id' },
	                { type: 'string', dataIndex: 'FirstName' },
	                { type: 'string', dataIndex: 'Email' }
	            &#93;
            });

            var pagingBar = new Ext.PagingToolbar({
                pageSize: 10,
                store: ds,
                displayInfo: true,
                displayMsg: 'Displaying Persons {0} - {1} of {2}',
                emptyMsg: "No Persons to display",
                plugins: filters
            });

            grid = new Ext.grid.GridPanel({
                store: ds,
                cm: columnModel,
                width: 500,
                autoHeight: true,
                title: 'Persons List',
                frame: true,
                loadMask: true,
                stripeRows: true,
                plugins: filters,
                bbar: pagingBar // paging bar on the bottom
            });

            grid.render('personGrid');
            grid.store.load({ params: { start: 0, limit: 10} });
        }
<div id="personGrid"

&#91;/sourcecode&#93;
<h4>Controller actions to support the grid's actions(get data/sort/filter data...etc)</h4>
A ExtJS grid can be fed data in various ways. i am going use a controller action to give the grid the data it needs to render it self. the data would be in json format. we would have a controller action like the following, that returns a JsonResult. we can use the Json method in the mvc framework to serialize the data to json with ease. i am doing it by constructing a anonymous type that hosts the data and then serializing it to json. please note that the following example uses the Entity Framework to deal with the back-end data. although this is example uses the EF. you can easily port it to use any other ORM technology(Linq...etc).

source of /Person/ListJson action


public JsonResult ListJson()
        {
            int totalOjectCount;
            var personsList = ExtJSGridFilterHelper.GetResults(Request, new ObjectEntities().Person,out totalOjectCount);
            var list = new ArrayList();
            foreach (var person in personsList) //populate data containers with read data
            {
                list.Add(new
                             {
                                 Id = person.ID,
                                 FirstName = person.FirstName,
                                 person.Email
                             });
            }
            return Json(new { dataitems = list.ToArray(), totalItems = totalOjectCount });
        }

note that the json result that is returned, basically contains a array of items and a another property called totalItems. this total items property tell the grid, the number of(obviously ) total items that it will have to display. this is helpfule for the grid when pagination is enabled. and you should make sure that this property is specified in your json output if you want the pagination to work correctly.

example json output that is produced by the above action

{"dataitems":[{"Id":"5","FirstName":"jhon Lalic","Email":"jhon@gmail.com"},{"Id":"6","FirstName":"Maureen Joesph","Email"
:"maureen@gmail.com"}],"totalItems":2}

this contains two records. and the totalItems property.

ExtJSGridFilterHelper is a helper class that harbours most of the logic related to implementing sorting/paging and filtering of data. i am not going to explain what the source code is doing, step by step. but you can always read the source ;). 

parsing of parameters sent by the grid…(for the full source code please look at the source of ExtJSGridFilterHelper)

parameters related to paging

  • start
  • limit

parameters related to the sorting

  • sort => the name of the property to be sorted(as given in the client side(aka field name))
  • dir => direction
if (sort != null) //do sorting
            {
                objectsList = query.OrderBy("it." + sort).ToList();
                if (dir == "DESC") objectsList.Reverse();
            }
            else
            {
                objectsList = query.ToList();
            }

parameters related to the filters

public Filter(int id, HttpRequestBase request)
            {
                Id = id;
                Field = request.Params[string.Format("filter[{0}][field]", id)];
                DataType = request.Params[string.Format("filter[{0}][data][type]", id)];
                DataValue = request.Params[string.Format("filter[{0}][data][value]", id)];
                Datacomparison = request.Params[string.Format("filter[{0}][data][comparison]", id)];
            }

how filters are processed, extract from the getExpression() method

</pre>
<pre>public FilterExpressionResult getExpression()
            {
                string expressionString = null;
                var expressionParams = new List(); //paramerters collection
                switch (DataType)
                {
                    case "string":
                        expressionString = string.Format("(it.{0} like '{1}%')", Field, DataValue);
                        break;
                    case "boolean":
                        expressionString = string.Format("(it.{0} = {1})", Field, (DataValue == "true") ? 1 : 0);
                        break;
                    case "numeric":
                        switch (Datacomparison)
                        {
                            case "gt":
                                Datacomparison = ">";
                                break;
                            case "lt":
                                Datacomparison = "";
                                break;
                            case "lt":
                                Datacomparison = "<";
                                break;
                            default:
                                Datacomparison = "=";
                                break;
                        }

                        expressionParams.Add(new ObjectParameter("Param" + Id, DateTime.Parse(DataValue)));
                        expressionString = string.Format("(it.{0} {2} {1})", Field, "@" + "Param" + Id, Datacomparison);
                        break;
                    case "list":
                        var split = DataValue.Split(new&#91;&#93; { ',' });
                        var r = new string&#91;split.Length&#93;;
                        for (var i = 0; i < split.Length; i++)
                        {
                            r&#91;i&#93; = string.Format("(it.{0} = '{1}')", Field, split&#91;i&#93;);
                        }
                        expressionString = string.Format("({0})", string.Join("OR", r));
                        break;
                }
<pre>

source of ExtJSGridFilterHelper

public class ExtJSGridFilterHelper
{
public static List GetResults(HttpRequestBase request, ObjectQuery query, out int totalOjectCount)
{
var sort = request.Params[“sort”];
var dir = request.Params[“dir”];

//get non null values
int intStart, intLimit;
if (!int.TryParse(request.Params[“start”], out intStart)) intStart = 0;
if (!int.TryParse(request.Params[“limit”], out intLimit)) intLimit = 10;

List objectsList;

totalOjectCount = query.Count();
var i = 0;
var exspressions = new List();
var parameters = new List();
while (true) //check for filters starting from 0, if one exists move to the next one(0 -> 1…), .
{
if (!Filter.checkExistence(i, request.Params)) break; //…if not stop looking further
var expression = new Filter(i, request).getExpression();
exspressions.Add(expression.Expression);
parameters.AddRange(expression.Parameters);
i++; //keep track of index
}
var exspression = string.Format(“({0})”, string.Join(“AND”, exspressions.ToArray()));
//build the final expression
if (exspression != “()”) query = query.Where(exspression, parameters.ToArray()); //filter collection on the expression

if (sort != null) //do sorting
{
objectsList = query.OrderBy(“it.” + sort).ToList();
if (dir == “DESC”) objectsList.Reverse();
}
else
{
objectsList = query.ToList();
}

if (intStart + intLimit > objectsList.Count)
intLimit = objectsList.Count – intStart; //make sure the range we select is valid
objectsList = objectsList.GetRange(intStart, intLimit);
return objectsList;
}

#region Nested type: Filter

public class Filter
{
public string Datacomparison { get; set; }
public string DataType { get; set; }
public string DataValue { get; set; }
public string Field { get; set; }

public int Id { get; set; }

public static bool checkExistence(int filterIndex, NameValueCollection @params)
{
return (@params[string.Format(“filter[{0}][field]”, filterIndex)] != null);
}

public Filter(int id, HttpRequestBase request)
{
Id = id;
Field = request.Params[string.Format(“filter[{0}][field]”, id)];
DataType = request.Params[string.Format(“filter[{0}][data][type]”, id)];
DataValue = request.Params[string.Format(“filter[{0}][data][value]”, id)];
Datacomparison = request.Params[string.Format(“filter[{0}][data][comparison]”, id)];
}

public FilterExpressionResult getExpression()
{
string expressionString = null;
var expressionParams = new List(); //paramerters collection
switch (DataType)
{
case “string”:
expressionString = string.Format(“(it.{0} like ‘{1}%’)”, Field, DataValue);
break;
case “boolean”:
expressionString = string.Format(“(it.{0} = {1})”, Field, (DataValue == “true”) ? 1 : 0);
break;
case “numeric”:
switch (Datacomparison)
{
case “gt”:
Datacomparison = “>”;
break;
case “lt”:
Datacomparison = “”;
break;
case “lt”:
Datacomparison = “<"; break; default: Datacomparison = "="; break; } expressionParams.Add(new ObjectParameter("Param" + Id, DateTime.Parse(DataValue))); expressionString = string.Format("(it.{0} {2} {1})", Field, "@" + "Param" + Id, Datacomparison); break; case "list": var split = DataValue.Split(new[] { ',' }); var r = new string[split.Length]; for (var i = 0; i < split.Length; i++) { r[i] = string.Format("(it.{0} = '{1}')", Field, split[i]); } expressionString = string.Format("({0})", string.Join("OR", r)); break; } return expressionString != null ? new FilterExpressionResult { Expression = expressionString, Parameters = expressionParams } : null; } #region Nested type: FilterExpressionResult public class FilterExpressionResult { public string Expression { get; set; } public List Parameters { get; set; } } #endregion } #endregion } [/sourcecode] ah! that's it for now. i might post some helpers that can be used in your views when you want to render the grid. the advantage of using this would be, so you won't need to repeat all that javascript code in each and every view that you want to display a grid in. hope this will be helpful to someone. cheers!

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