Question

I have model

public class UploadOptionModel
{
    public UploadOptionModel()
    {

        OutputFormat = outputFormatList.Select(i => new SelectListItem
                 {
                     Text = i,
                     Value = i
                 });
    }

    public string Email { get; set; }        
    public IEnumerable<SelectListItem> OutputFormat { get; set; }
}

and View

@model PC.Models.UploadOptionModel
@using (Html.BeginForm())
{
    @Html.TextBoxFor(p => p.Email)
    @Html.DropDownList("OutputFormat", Model.OutputFormat)
}

I am trying to submit the form above using Ajax call and bind it to model

//Calling ValidateFile Action controller
 $.ajax({
                    url: '@Url.Action("ValidateFile", "Converter")',
                    data: JSON.stringify({ file: fileName, formData: serializedForm }),
                    contentType: 'application/json',
                    type: 'POST',
                    success: function (response) {
                        if (response.result) {
                        } else {
                            RemoveFile(fileName);
                        }
                    }
                });

    function serializeForm() {        
        var data = $("form").serializeArray();
        var formData = {};
        for (var i = 0; i < data.length; i++) {
            formData[data[i].name] = data[i].value;
        }

        return formData;
    }

The ValidateFile action

[HttpPost]
public JsonResult ValidateFile(string file, UploadOptionModel formData)
{
}

The problem is that UploadOptionModel.OutputFormat is not binding. I can’t read selected dropdown value. UploadOptionModel.Email field is bind successfully.

Answer 1

You should have another property in your Model class, where you bind the selected value of the dropdownlist.
So in your model add something like

public string OutputFormatSelected { get; set; }

And then use it in your view, this way:

@model PC.Models.UploadOptionModel
@using (Html.BeginForm())
{
    @Html.TextBoxFor(p => p.Email)
    @Html.DropDownListFor( m => m.OutputFormatSelected, m.OutputFormat)
}

Your problem was that you wee binding both the list of elements and the result to the same property