Setup value provider for dropdown list field in Sitecore forms using IFieldValueProvider

Question

I have a doubt regarding setting up a value provider for prefilling Sitecore forms, I can see there are examples for simple text input fields, and it's working, but when I try to set up a value provider for a dropdown list field it's not working.

I tried below but had no luck, can someone help me to figure out what am doing wrong here?

    public class CountryListValueProvider : IFieldValueProvider
        {
            public FieldValueProviderContext ValueProviderContext { get; set; }
            public object GetValue(string parameters)
            {
                var countries = GetCountries();
                var countrList = new ListFieldItemCollection();
                foreach (var country in countries.data)
                {
                    countrList.Add(new ListFieldItem
                    {
                        Text = country.code,
                        Value = country.value
                    });
                }
                switch (parameters)
                {
                    case "countrList":
                        return countrList;
                    default:
                        return string.Empty;
                }
            }
        }

Or do I need to try something else, like using IListDataSourceProvider?

Answer 1

The main use of Value Provider is for prefilling Sitecore forms. So Sitecore has described how to implement that using the below article.

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

But in your case, if you want to pre-fill your value for a dropdown list then you only need to pass a list of strings like this. For example, if the value you want pre-fill is called "prefillvalue", then you code will be like this.

public object GetValue(string parameters)
{
   return new List<string> {"prefillvalue"};
}

Read this article for more details.

http://onelittlespark.bartverdonck.be/value-provider-on-list-components/