I want to do client side validation of listbox. We can't move all items from one listbox to another. There should be at least one item in the listbox.
Listbox should not be blank completely as there should be at least one item in it.
Can you please guide me how to do it. Appreciated for your help.
Class
public class NumberClass
{
public string currentLeftNumbers { get; set; }
public IEnumerable<SelectListItem> leftnumbers { get; set; }
public IEnumerable<int> leftSelectednumbers { get; set; }
public string currentRightNumbers { get; set; }
public IEnumerable<SelectListItem> rightnumbers { get; set; }
public IEnumerable<int> rightSelectednumbers { get; set; }
}
Controller
[HttpGet]
public ActionResult Index()
{
List<int> items = new List<int>();
for (int i = 1; i <= 20; i++)
{
items.Add(i);
}
NumberClass num = GetModel(items, new List<int>());
return View(num);
}
[HttpPost]
public ActionResult Index(NumberClass model)
{
List<int> left = GetNumbers(model.currentLeftNumbers);
List<int> right = GetNumbers(model.currentRightNumbers);
if (model.leftSelectednumbers != null)
{
foreach (var i in model.leftSelectednumbers)
{
left.Remove(i);
right.Add(i);
}
}
if (model.rightSelectednumbers != null)
{
foreach (var i in model.rightSelectednumbers)
{
right.Remove(i);
left.Add(i);
}
}
return View(GetModel(left, right));
}
private List<int> GetNumbers(string numbers)
{
if (string.IsNullOrWhiteSpace(numbers))
{
return new List<int>();
}
else
{
return numbers.Split(new char[] { ',' },
StringSplitOptions.RemoveEmptyEntries).Select(n => int.Parse(n)).ToList();
}
}
private NumberClass GetModel(IEnumerable<int> left, IEnumerable<int> right)
{
NumberClass model = new NumberClass();
if (left.Any())
{
model.currentLeftNumbers = left.Select(n => n.ToString()).Aggregate((x, y) => x + "," + y);
model.leftnumbers = left.OrderBy(x => x).Select(n => new SelectListItem { Value = n.ToString(), Text = n.ToString() });
}
else
{
model.leftnumbers = new List<SelectListItem>();
}
if (right.Any())
{
model.currentRightNumbers = right.Select(n => n.ToString()).Aggregate((x, y) => x + "," + y);
model.rightnumbers = right.OrderBy(x => x).Select(n => new SelectListItem { Value = n.ToString(), Text = n.ToString() });
}
else
{
model.rightnumbers= new List<SelectListItem>();
}
return model;
}
Index.cshtml
@using (Html.BeginForm())
{
<input type="hidden" name="CurrentLeftNumbers" value="@Model.currentLeftNumbers"/>
<div class="col-md-6" style="font-family:Arial">
@Html.ListBoxFor(m => m.leftSelectednumbers, Model.leftnumbers, new { size = 20, @class = "listBox" })
<br />
<input type="submit" value="move right" />
</div>
<input type="hidden" name="CurrentRightNumbers" value="@Model.currentRightNumbers" />
<div class="col-md-6" style="font-family:Arial">
@Html.ListBoxFor(m => m.rightSelectednumbers, Model.rightnumbers, new { size = 20, @class = "listBox" })
<br />
<input type="submit" value="move left" />
</div>
}
