The Textarea Tag Helper

The role of the textarea tag helper is to render and HMTL textarea element for capturing multiline text.

The textarea tag helper has one attribute:

Attribute	Description
for	An expression to be evaluated against the current page model

Notes

The textarea tag helper renders id and name attributes based on the name of the model property passed to the asp-for attribute. It also renders any associated data attributes required for property validation.

The MainText property below has a maximum length of 300 applied to it:

[BindProperty, MaxLength(300)]
public string MainText { get; set; }

This is passed to the value of the asp-for attribute of the tag helper:

<textarea asp-for="MainText"></textarea>

The resulting HTML includes the validation attributes for unobtrusive validation as well as the appropriate name attribute value for model binding:

<textarea 
    data-val="true" 
    data-val-maxlength="The field MainText must be a string or array type with a maximum length of &#x27;300&#x27;." 
    data-val-maxlength-max="300" 
    id="MainText" 
    name="MainText">