Custom HTML Helper with Page Mode Rendering

aditya pewekar

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15 Feb 2019CPOL1 min read

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Create custom HTML helper to manage Page Mode like View (Readonly) and Edit/Add (Editable)

Introduction

How do we make an entire Web Page editable or readonly based on certain conditions without using a bunch of If else conditions? While searching for an answer to this question, I came across lots of ways, i.e., as follows:

We can create two different views and can call based on the required condition:
Razor
```
@if (readonly)
{
     @Html.DisplayForView()
}
else
{
     @Html.EditorForView()
}
```
In this, we will need to create two different partial views, which seems to be code redundancy.
The second approach I found is to set the If else condition in the @Html.Control:
Razor
```
@Html.EditorFor(x => x.Name,IsReadonly ? (object) new 
            { htmlAttributes = new { @readonly = "readonly"} }
                    : new { htmlAttributes = new { @readonly = ""} })
```
In this case, if my form has multiple EditorFor, then it becomes a tedious job to do the conditioning and also, your view becomes clumsy and heavy.

So just to manage everything in one place, I created a Custom HTML Helper and set the readonly attribute based on the Page Mode which I managed to pass using ViewBag. Following is the code for the same.

Index.cshtml

Razor

@{
    Layout = null;
}
@using CustomHTMLHelperPageMode.Helper
@model CustomHTMLHelperPageMode.Models.User

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>

    <link rel="stylesheet" 
     href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.0/css/bootstrap.min.css">

    <!-- jQuery library -->
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

    <!-- Latest compiled JavaScript -->
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.0/js/bootstrap.min.js"></script>
</head>
<body>
    <div>
        @using (Html.BeginForm())
        {
            <div class="container">
                <div class="form-group">
                    @Html.LabelFor(model => model.Name)
                    @Html.PageModeTextBoxFor(model => model.Name, 
                          new { htmlAttributes = new { @class = "form-control" } })
                </div>
                <div class="form-group">
                    @Html.LabelFor(model => model.Phone)
                    @Html.PageModeTextBoxFor(model => model.Phone, 
                          new { htmlAttributes = new { @class = "form-control" } })
                </div>
                <div class="form-group">
                    @Html.LabelFor(model => model.Email)
                    @Html.PageModeTextBoxFor(model => model.Email, 
                          new { htmlAttributes = new { @class = "form-control" } })
                </div>
                <div class="form-group">
                    @Html.LabelFor(model => model.Address)
                    @Html.PageModeTextBoxFor(model => model.Address, 
                          new { htmlAttributes = new { @class = "form-control" } })
                </div>

                @if (ViewBag.PageMode != "View")
                {
                    <input type="submit" value="Create" class="btn btn-default" />
                }

                </div>
                }
            </div>
</body>
</html>

HomeController.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace CustomHTMLHelperPageMode.Controllers
{
    public class HomeController : Controller
    {
        // GET: Home
        public ActionResult Index()
        {
            return View();
        }

        public ActionResult ViewIndex()
        {
            ViewBag.PageMode = "View";
            return View("Index");
        }
    }
}

PageModeTextBox.cs (Helper)

using System;
using System.Collections.Generic;
using System.Web.Mvc.Html;

namespace CustomHTMLHelperPageMode.Helper
{
    public static class PageModeTextBox
    {
        public static System.Web.Mvc.MvcHtmlString PageModeTextBoxFor<TModel, TValue>
       (this System.Web.Mvc.HtmlHelper<TModel> html,
       System.Linq.Expressions.Expression<Func<TModel, TValue>> expression,
       object htmlAttributes = null, bool readOnly = false)
        {

            System.Web.Mvc.ModelMetadata oModelMetadata =
                System.Web.Mvc.ModelMetadata.FromLambdaExpression(expression, html.ViewData);

            Dictionary<string, object> dynamicAttribute = new Dictionary<string, object>();

            foreach(var prop in htmlAttributes.GetType().GetProperties())
            {
                if(prop.Name== "htmlAttributes")
                {
                    var propValue = prop.GetValue(htmlAttributes, null);
                    foreach (var innerProp in propValue.GetType().GetProperties())
                    {
                        dynamicAttribute.Add(innerProp.Name, innerProp.GetValue(propValue, null));
                    }
                }
                else
                {
                    dynamicAttribute.Add(prop.Name, prop.GetValue(prop));
                }
            }            

            if (html.ViewBag.PageMode == "View")
            {
                if (dynamicAttribute.ContainsKey("readonly") == false)
                {
                    dynamicAttribute.Add("readonly", "read-only");
                }
            }     

            return (html.TextBoxFor(expression, dynamicAttribute));
        }
    }
}

User.cs (Model)

using System.ComponentModel;

namespace CustomHTMLHelperPageMode.Models
{
    public class User
    {
        [DisplayName("Name")]
        public string Name { get; set; }
        [DisplayName("Contact No")]
        public string Phone { get; set; }
        [DisplayName("Email")]
        public string Email { get; set; }
        [DisplayName("Address")]
        public string Address { get; set; }
    }
}

Edit Mode

View Mode

The sample code is available on GitHub.

If any of the readers have an improved and better workflow for the above requirement, I would like to add the same to my knowledge.

CODE IT !!!

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Written By

aditya pewekar

India

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