Assign a value to a hidden field on Experience Forms

Question

I have added a hidden field on a Sitecore (9.2) form. I want to assign some value to that hidden field when the form loads. Can anyone please tell me how I can achieve that?

Answer 1

You need to add a custom field in Sitecore forms. You may refer to some blogs related to it. For example in my case I've created a custom Sitecore field called "hidden field". When I add it to Sitecore form, it gives me options to add some values like this.

And in the code behind, I bind these values like this.

using Sitecore.Data.Items;
using Sitecore.Diagnostics;
using Sitecore.ExperienceForms.Mvc.Models.Fields;

namespace Site.Feature.Forms.Forms.Controls.HiddenField
{

[System.Serializable]
public class HiddenFieldModel : InputViewModel<string>
{
    public string FromEmail { get; set; }

    protected override void InitItemProperties(Item item)
    {
        Assert.ArgumentNotNull(item, "item");
        base.InitItemProperties(item);

        FromEmail = item?.Fields["From Email"]?.Value;
    }

    protected override void UpdateItemFields(Item item)
    {
        Assert.ArgumentNotNull(item, "item");
        base.UpdateItemFields(item);

        var fromEmail = item.Fields["From Email"];
        if (fromEmail != null)
            fromEmail.SetValue(FromEmail, true);
    }
}
 }

And on the view, you can access the value like this.

@using System.Web.Mvc.Html
@model Site.Feature.Forms.Forms.Controls.HiddenField.HiddenFieldModel

<input type="hidden" id="@Html.IdFor(m => Model.FromEmail)" name="@Html.NameFor(m => Model.FromEmail)" value="@Model.FromEmail" />

Answer 2

Make sure your custom hidden field component supports the value provider mechanism.

You can create a value provider to fill the hidden field.

https://doc.sitecore.com/developers/93/sitecore-experience-manager/en/walkthrough--setting-up-a-value-provider-for-prefilling-forms.html