Below is a snippet of my custom postcode field.

I am having issues when using this field. It never hits the breakpoint that i set on Process value.

public class PostcodeField : FieldType { public PostcodeField() { Id = new Guid("06681d21-021e-43d6-8932-942f2092fe2f"); Name = "Postcode"; Description = "Renders a textbox and button for postcode"; DataType = FieldDataType.LongString; }

    private string _houseNumber;
    private string _street;
    private string _town;
    private string _postCode;

    public override string RenderPreview()
    {
        var postcode = new StringBuilder();
        postcode.Append("<input type=\"text\" name =\"HouseNuumber\"/>");
        postcode.Append("<br/>");
        postcode.Append("<input type=\"text\" name =\"Street\"/>");
        postcode.Append("<br/>");
        postcode.Append("<input type=\"text\" name =\"Town\"/>");
        postcode.Append("<br/>");
        postcode.Append("<input type=\"text\" name =\"Postcode\"/>");
        postcode.Append("<br/>");
        postcode.Append("<input type=\"button\" value=\"Find Address\" name=\"FindAddressBtn\"/>");
        postcode.Append("<br/>");
        return postcode.ToString();
    }

    public override string RenderPreviewWithPrevalues(List<object> prevalues)
    {
        return RenderPreview();
    }

    //public override List<Exception> Validate(HttpContextBase httpContext)
    //{
    //    _houseNumber = httpContext.Request["HouseNumber"];
    //    _street = httpContext.Request["Street"];
    //    _town = httpContext.Request["Town"];
    //    _postCode = httpContext.Request["Postcode"];

    //    var postcodeValidator = new PostCodeFieldValidator(_postCode, _street, _houseNumber, _town);
    //    var results = postcodeValidator.Validate();
    //    if(results.Any())
    //    {
    //        var exceptions = new List<Exception>();
    //        results.ForEach(x => exceptions.Add(new Exception(x)));
    //        return exceptions;
    //    }
    //    return null;
    //}

    public override List<object> ProcessValue(HttpContextBase httpContext)
    {
        var vals = new List<object>();

        _houseNumber = _houseNumber== null? httpContext.Request["HouseNumber"]: String.Empty;
        _street = _street==null? httpContext.Request["Street"] : String.Empty;
        _town = _town ==null? httpContext.Request["Town"] : String.Empty;
        _postCode = _postCode == null? httpContext.Request["Postcode"] : String.Empty;

        vals.Add(string.Concat(_houseNumber, " ", _street, " ", _town, " ", _postCode));



        //var fullAddress = String.Format("{0};{1};{2};{3}", _houseNumber, _street, _town, _postCode);

        //vals.Add(fullAddress);
        return vals;
    }
}

Here is snippet for .cshtml. Please help I am not sure what i could be doing wrong

<div class="appFormItemWrapper" id="FindAddressBtnWrapper">
</div>
<div style="display: none;" class="validation" id="FindAddressBtnValidation">
    Please press the Find Address button.</div>
<div style="display: none;" class="validation" id="ManualAddressValidation">
    Postcode not found. Please enter full address manually
</div>
<div class="appFormItemWrapper fullWidth" id="SelectAddressWrapper">
    <label for="SelectAddress"> Select address</label>
    <select id="SelectAddress" data-role="none" class="appFormSelect big appFormSection3" name="SelectAddress" value="@Request["SelectAddress"]">
        <option selected="selected" value="">Choose</option>
    </select>
</div>
<div id="InputAddressWrapper">
    <div class="appFormItemWrapper">
        <label for="HouseNumber">
            House Name / Number</label>
        <input type="text" data-role="none" name="HouseNumber" id="HouseNumber" value="@Request.Form["HouseNumber"]" />
    </div>
    <div class="appFormItemWrapper">
        <label for="Street">
            Street</label>
        <input type="text" data-role="none" name="Street" id="Street" value="@Request["Street"]" />
    </div>
    <div class="appFormItemWrapper">
        <label for="Town">
            Town / City</label>
        <input type="text" data-role="none" name="Town" id="Town" value="@Request["Town"]" />
    </div>
    <div class="clearAll">
    </div>
    <input type="hidden" name="SelectAddressIsVisible" id="SelectAddressIsVisible" value="0" />
    <input type="hidden" name="InputAddressIsVisible" id="InputAddressIsVisible" value="0" />
</div>