Chapter_5_Forms_Html_Helpers.md

Forms and HTML Helpers

• A form is a container for input elements: buttons, checkboxes, and more. Input elements in a form enable a user to enter information into a page and submit information to a server.
• There are two main attributes of a form tag: the action and the method
• action attribute tells a web browser where to send the information.
• method attribute tells the browser whether to use HTTP POST or HTTP GET when sending the information. Default value is HTTP GET

Example:

<form action='/Student/Create' method="post">
  <input name="fullname" type="text" />
  <input type="submit" value="Submit" />
</form>

HTML Helpers

These are methods to make views easy to author. Most of them output HTML markup.
Some HTML Helpers:

• BeginForm
  This helps to build a robust form. Example:

@using (Html.BeginForm("Create",  "Student", FormMethod.Get)) {
  <input name="fullname" type="text" />
  <input type="submit" value="Submit" />
}

• Validation Helpers
  • Html.ValidationSummary
    This displays unordered list of all validation errors in the ModelState dicitionary.
  • @Html.ValidationMessage When an error exists for a particular field in the ModelState dicitionary, you can use ValidationMessage helper to display that message.
• Input HTML Helpers
  • @Html.TextBox
    TextBox helper renders an input tag with the type attribute set to text. Example:

  @Html.TextBox("fullname", Model.FullName) results <input id="fullname" name="fullname" type="text" />

  • @Html.TextArea
    This will render <textarea> element for multiline entry.
  • @Html.Label
    This return <label /> element using the string parameter to determine rendered text and for attribute value.
  • @Html.DropDownList and @Html.ListBox
    Both of these return <select /> element. DropDownList allows you to select single element while Listbox allows you to select multiple values.
  • Other Input helpers: @Html.Hidden, @Htm.RadioButton, @Html.Password, @Html.Checkbox.
• Rendering Helpers
  These helpers produce links to other resources inside an application. Examples: @Html.ActionLink and @Html.RouteLink
• Strongly Typed Helpers
  with strongly typed helpers, you pass a lambda expression to specify a model property for rendering. They have same name as other helpers but with For suffix. Examples: @Html.TextBoxFor, @Html.LabelFor, @Html.DropDownListFor etc.