Changing html img by value comes from json data which gets database value with some nullable fields

i have a database table that holds the following fields:

product_id | design_id | material_id | color_id | picture1 (picture name field)..

design_id, material_id and color_id are nullable fields in the database..

I am using linqtosql for it.

I have dropdownlists for the id fields. The dropdowns are in order as so:

Product>Design>Material>Color

This is an unbreakable line. (yeah, I figured how to do this)

When I choose the first dropdown item (Product list item) I want my picture to change. Then when choosing further dropdown items I want it to change again. (for example: after product is chosen when a design is chosen I want it to find the picture which matches product and design id (which can be found in the database).

So if product=1, design=0, material=0 and color=0 the picture for this situation will be displayed and if product=3, design=6, material=2 and color=9 the picture for this different situation will be displayed.

EDIT : I can now change the image but cant display on the screen only the link comes..

Here is new code:

jquery

    $.getJSON('@Url.Content("~/Admin/GetPictures/")', { productId: prod, designId: des, matsid: mats, colid: col }, function (data) {
        $.each(data, function (i, c) {
            /*$("img#re开发者_如何转开发s").attr("src", "../../Pictures/" + c.Text).attr("alt", "../../Pictures/" + c.Text).attr("width", "100%");*/
              $("img#res").attr({ 'src': '../../Pictures/' + c.Text, 'alt': '../../Pictures/' + c.Text, 'width': '100%' });
        })
    })

Found a solution for this problem :

controller

public JsonResult GetPictures(int productId, int? designId, int? matsid, int? colid)
{
    int? d = 0;
    int? m = 0;
    int? c = 0;
    if (designId == null) { d = 0; } else if (designId != null) { d = designId; };
    if (matsid == null) { m = 0; } else if (matsid != null) { m = matsid;};
    if (colid == null) { c = 0; } else if (colid != null) { c = colid; };
    IEnumerable<SelectListItem> PictureItems = db.Pictures.Where(x => x.product_id == productId & x.design_id == d & x.material_id == m & x.color_id == c).AsEnumerable().Select(x => new SelectListItem()
    {
        Text = x.picture1,
        Value = x.id.ToString().TrimEnd() 
    });
    SelectList data = new SelectList(PictureItems, "Value", "Text");
    return Json(data, JsonRequestBehavior.AllowGet);
}

view

$.getJSON('@Url.Content("~/Admin/GetPictures/")', { productId: prod, designId: des, matsid: mats, colid: col }, function (data) {
    $.each(data, function (i, c) {
        $("img#res").attr("src", "../../Pictures/" + c.Text).attr("alt", "../../Pictures/" + c.Text);
    })
})