Skip to main content

Storing and restoring Kendo Grid state from Database

There is no any built in way to store entire grid state into database and restore back again with all filters, groups, aggregates, page and page size.

At first, I was trying to restore only filters by looking through DataSourceRequest. DataSourceRequest is kind of communication medium between client and server for the operation we do on grid. All the request comes via DataSourceRequest. In previous approach, I was trying to store IFileDescriptor interface which come with class FileDescriptor by looping through filters and serializing into string for saving into database but this IFileDescriptor can also contain CompositeFilterDescriptor which can be nested in nested object which are very tricky to handle.

So, I had decompiled entire Kendo.MVC library and found out that all Kendo MVC controls are derived from “JsonObject”. It is there own implementation with ”Serialize” abstract function and “ToJson” function. In controls they are overriding “Serialize” method which depicts the object found on JavaScript for Kendo control. The “ToJson” function is returning “IDictionary<string,object>”. This is all we need. We can transform “IDictionary<string,object>” from “ToJson” and store into database and on initialization of grid on client side we can put these values directly on Kendo Grid.

Please note that serialization/direct storing could have been done directly on JavaScript level but there is no event associated to filters and might be same with other as well.

Let's start by defining Kendo MVC Grid control but we will not populate grid data right away while rendering. We got to initialize settings first (grid state from DB) and then populate data and restore grid state through “DataSource”. To stop grid data population Kendo MVC helper has “AutoBind()” function which can be set as “AutoBind(false)” .
Here is the entire grid sample:

 @(Html.Kendo().Grid<ViewModel>()  
 .Name("GridSample")  
 .Columns(columns =>  
 {  
      columns.Bound(vm => vm.LastName);  
      columns.Bound( vm => vm.FirstName);  
      columns.Bound( vm => vm.MiddleName);  
      columns.Bound( vm => vm.Id).Title("Id #");  
 })  
 .AutoBind(false)  
 .DataSource(datasource => datasource  
      .Ajax()  
      .Read(read => read.Action("GetAllData", "SampleGrid", new { area = "" })  
                     )  
      .PageSize(20)  
 )  
 .Reorderable(reorder => reorder.Columns(true))  
 .Pageable()  
 .Filterable()  
 .Sortable()  
 .ColumnMenu()  
 .Scrollable()  
 .Selectable(selectable => selectable.Mode(GridSelectionMode.Single)))  
 // JavaScript call  
 <script type=”text/javascript”>  
 RestoreGridSetting("GridSample")  
 </script>  

After setting up grid we need to initialize grid with data stored into DB through JavaScript.

 function RestoreGridSetting (gridId) {  
      if (gridId === undefined || gridId === null) {  
           return;  
      }  
      // Select row  
      var grid = $('#' + gridId).data('kendoGrid');  
      if (grid === undefined) {  
           return;  
      }  
      // Initialize columns  
      $.get('/api/userprofilegrid/' + gridId.toLowerCase(), function (data) {  
           if (data === undefined || data === null) {  
                return;  
           }  
           // Set values from result of WebAPI call  
           grid.dataSource.filter(JSON.parse(data.Filters));  
           grid.dataSource.sort(JSON.parse(data.Sorts));  
           grid.dataSource.group(JSON.parse(data.Groups));  
           grid.dataSource.aggregate(JSON.parse(data.Aggregates));  
      });  
 }  

If the first request comes it will get information from WebApi and restore on grid via grid's datasource.
Now, let's look into action request which will be called from Grid control.

 .Read(read => read.Action("GetAllData", "SampleGrid", new { area = "" })  

Everything will remain as it is (DataSourceRequest) just that we need to save data into database which would be resulted by WebAPI call from JavaScript. So, here is server side code for GetAllData.

 var gridDetail = // TODO: Get object from DB;  
 if (gridDetail == null)  
 {  
      return;  
 }  
 gridDetail.Aggregates = JsonConvert.SerializeObject(request.Aggregates.OfType<JsonObject>().ToJson());  
 gridDetail.Filters = JsonConvert.SerializeObject(request.Filters.OfType<JsonObject>().ToJson());  
 gridDetail.Groups = JsonConvert.SerializeObject(request.Groups.OfType<JsonObject>().ToJson());  
 gridDetail.PageSize = request.PageSize;  
 gridDetail.Sorts = JsonConvert.SerializeObject(request.Sorts.OfType<JsonObject>().ToJson());  
 //gridDetail.PageLocation = request.Page;  
 // TODO: Save object  

The above function is using Newtonsoft.JSON library to parse data from “IDictionary<string,object>” which is generated form “ToJson” call.

To summarize all of them as steps
1. Create grid control by setting “Autobind” as false.
2. Through AJAX call get grid state model and set the value into grid's datasource.
3. On server side grid's action to retrieve data, save DataSourceRequest properties with the help of “ToJson” and "JsonCovert".


NOTE: In this article, I have not covered restoring hidden columns and column grid position. There are plenty of resource that can be followed to achieve it.

Comments

Popular posts from this blog

Elegantly dealing with TimeZones in MVC Core / WebApi

In any new application handling TimeZone/DateTime is mostly least priority and generally, if someone is concerned then it would be handled by using DateTime.UtcNow on codes while creating current dates and converting incoming Date to UTC to save on servers. Basically, the process is followed by saving DateTime to UTC format in a database and keep converting data to native format based on user region or single region in the application's presentation layer. The above is tedious work and have to be followed religiously. If any developer misses out the manual conversion, then that area of code/view would not work. With newer frameworks, there are flexible ways to deal/intercept incoming or outgoing calls to simplify conversion of TimeZones. These are steps/process to achieve it. 1. Central code for storing user's state about TimeZone. Also, central code for conversion logic based on TimeZones. 2. Dependency injection for the above class to ...

Using Redis distributed cache in dotnet core with helper extension methods

Redis cache is out process cache provider for a distributed environment. It is popular in Azure Cloud solution, but it also has a standalone application to operate upon in case of small enterprises application. How to install Redis Cache on a local machine? Redis can be used as a local cache server too on our local machines. At first install, Chocolatey https://chocolatey.org/ , to make installation of Redis easy. Also, the version under Chocolatey supports more commands and compatible with Official Cache package from Microsoft. After Chocolatey installation hit choco install redis-64 . Once the installation is done, we can start the server by running redis-server . Distributed Cache package and registration dotnet core provides IDistributedCache interface which can be overrided with our own implementation. That is one of the beauties of dotnet core, having DI implementation at heart of framework. There is already nuget package available to override IDistributedCache i...

Handling JSON DateTime format on Asp.Net Core

This is a very simple trick to handle JSON date format on AspNet Core by global settings. This can be applicable for the older version as well. In a newer version by default, .Net depends upon Newtonsoft to process any JSON data. Newtonsoft depends upon Newtonsoft.Json.Converters.IsoDateTimeConverter class for processing date which in turns adds timezone for JSON data format. There is a global setting available for same that can be adjusted according to requirement. So, for example, we want to set default formatting to US format, we just need this code. services.AddMvc() .AddJsonOptions(options => { options.SerializerSettings.DateTimeZoneHandling = "MM/dd/yyyy HH:mm:ss"; });

Architecture solution composting Repository Pattern, Unit Of Work, Dependency Injection, Factory Pattern and others

Project architecture is like garden, we plant the things in certain order and eventually they grow in similar manner. If things are planted well then they will all look(work) great and easier to manage. If they grow as cumbersome it would difficult to maintain and with time more problems would be happening in maintenance. There is no any fixed or known approach to decide project architecture and specially with Agile Methodology. In Agile Methodology, we cannot predict how our end products will look like similarly we cannot say a certain architecture will fit well for entire development lifespan for project. So, the best thing is to modify the architecture as per our application growth. I understand that it sounds good but will be far more problematic with actual development. If it is left as it is then more problems will arise with time. Just think about moving plant vs a full grown tree. Coming to technical side, In this article, I will be explaining about the various techniques ...

Trim text in MVC Core through Model Binder

Trimming text can be done on client side codes, but I believe it is most suitable on MVC Model Binder since it would be at one place on infrastructure level which would be free from any manual intervention of developer. This would allow every post request to be processed and converted to a trimmed string. Let us start by creating Model binder using Microsoft.AspNetCore.Mvc.ModelBinding; using System; using System.Threading.Tasks; public class TrimmingModelBinder : IModelBinder { private readonly IModelBinder FallbackBinder; public TrimmingModelBinder(IModelBinder fallbackBinder) { FallbackBinder = fallbackBinder ?? throw new ArgumentNullException(nameof(fallbackBinder)); } public Task BindModelAsync(ModelBindingContext bindingContext) { if (bindingContext == null) { throw new ArgumentNullException(nameof(bindingContext)); } var valueProviderResult = bindingContext.ValueProvider.GetValue(bin...

Making FluentValidation compatible with Swagger including Enum or fixed List support

FluentValidation is not directly compatible with Swagger API to validate models. But they do provide an interface through which we can compose Swagger validation manually. That means we look under FluentValidation validators and compose Swagger validator properties to make it compatible. More of all mapping by reading information from FluentValidation and setting it to Swagger Model Schema. These can be done on any custom validation from FluentValidation too just that proper schema property has to be available from Swagger. Custom validation from Enum/List values on FluentValidation using FluentValidation.Validators; using System.Collections.Generic; using System.Linq; using static System.String; /// <summary> /// Validator as per list of items. /// </summary> /// <seealso cref="PropertyValidator" /> public class FixedListValidator : PropertyValidator { /// <summary> /// Gets the valid items /// <...

Using LINQ to Entity efficiently with First/FirstOrDefault/Last/LastOrDefault/Single/SingleOrDefault

We generally use these extension methods First/FirstOrDefault/Last/LastOrDefault/Single/SingleOrDefault with predicates like ctx=> ctx.Model.FirstOrDefault(item => item.Id == 1 ) Or ctx=> ctx.Model.Where(item => item.Id == 1 ).FirstOrDefault() What is the problem with these? FirstOrDefault or similar methods immediately loads all data at once. So, let's say we have fifty columns on table then all those columns data would be retrieved from DB and saved into memory. This link gives a fair idea of different function behavior.  https://msdn.microsoft.com/en-us/library/bb882641.aspx .  So, even if we require only one value from selected field it retrieves all values. What is the solution? The solution is pretty simple. Whenever we need selected items better to do projection before calling FirstOrDefault or similar methods. Ex: Selecting single item ctx.Model.Where(itm => itm.Id == 1) .Select(itm => itm.Name).FirstO...

LDAP with ASP.Net Identity Core in MVC with project.json

Lightweight Directory Access Protocol (LDAP), the name itself explain it. An application protocol used over an IP network to access the distributed directory information service. The first and foremost thing is to add references for consuming LDAP. This has to be done by adding reference from Global Assembly Cache (GAC) into project.json "frameworks": { "net461": { "frameworkAssemblies": { "System.DirectoryServices": "4.0.0.0", "System.DirectoryServices.AccountManagement": "4.0.0.0" } } }, These  System.DirectoryServices  and  System.DirectoryServices.AccountManagement  references are used to consume LDAP functionality. It is always better to have an abstraction for irrelevant items in consuming part. For an example, the application does not need to know about PrincipalContext or any other dependent items from those two references to make it extensible. So, we can begin wi...

Channel, ChannelReader and ChannelWriter to manage data streams in multi-threading environment

I came across Channel class while working with SignalR which looks really interesting. By looking into NuGet packages ( https://www.nuget.org/packages/System.Threading.Channels ), it seems just 4 months old. The Channel class provides infrastructure to have multiple reads and write simuletensely through it's Reader and Writer properties. This is where it is handy in case of SignalR where data streaming needs to be done but is not just limited to that but wherever something needs to be read/write/combination of both in a multi-threading environment. In my case with SignalR, I had to stream stock data at a regular interval of time. public ChannelReader<StockData> StreamStock() { var channel = Channel.CreateUnbounded<StockData>(); _stockManager.OnStockData = stockData => { channel.Writer.TryWrite(stockData); }; return channel.Reader; } The SignalR keeps return type of ChannelReader<StockData> open so that whatev...

Blazor 0.5.0 Interop JavaScript from C# and C# to JavaScript call

Blazor provides two-way communication from JS to C# and C# to JS which is called Interop. The version upgrade to Blazor 0.5.0 changed the approach in interactions between cshtml and JS files. The newer version simplifies JS calling by avoiding pre-registration of JS function. In this article, we would see how to call a JS method by passing multiple parameters from cshtml and parameterized call from JS to cshtml. The scenario that is used in this article has a Kendo AutoComplete to search book and populate information based on the selection. An example of a call to JS from cshtml await JSRuntime.Current.InvokeAsync<string>( "searchBook.Init", "#SearchTitle", new DotNetObjectRef(this)); Takeaways from the above example: - JSRuntime.Current give environment to execute out-process JS. - InvokeAsync is a function that would allow executing the JS function. - The searchBook.Init is a JS function call, we would see it in details in the second sec...