ASP.NET MVC Checkbox Group
asp.net-mvc, checkbox
Solution
I don't know how to solve your problem, but you could define your checkboxes with this code:
<%= Html.CheckBox("n[0]") %><%= Html.Hidden("n[0]",false) %>
<%= Html.CheckBox("n[1]") %><%= Html.Hidden("n[1]",false) %>
<%= Html.CheckBox("n[2]") %><%= Html.Hidden("n[2]",false) %>
Hidden fields are needed, because if checkbox is not checked, form doesn't send any value. With hidden field it sends false.
Your post method will be:
[HttpPost]
public ActionResult Test(bool[] n)
{
return View();
}
It may not be optimal and I am open to comments, but it works:)
EDIT
Extended version:
<%= Html.CheckBox("n[0].Checked") %><%= Html.Hidden("n[0].Value",32) %><%= Html.Hidden("n[0].Checked",false) %>
<%= Html.CheckBox("n[1].Checked") %><%= Html.Hidden("n[1].Value",55) %><%= Html.Hidden("n[1].Checked",false) %>
<%= Html.CheckBox("n[2].Checked") %><%= Html.Hidden("n[2].Value",76) %><%= Html.Hidden("n[2].Checked",false) %>
Your post method will be:
[HttpPost]
public ActionResult Test(CheckedValue[] n)
{
return View();
}
public class CheckedValue
{
public bool Checked { get; set; }
public bool Value { get; set; }
}
I wrote it without VS, so it may need little correction.
Problem
I am trying to formulate a work-around for the lack of a "checkbox group" in ASP.NET MVC. The typical way to implement this is to have check boxes of the same name, each with the value it represents. ``` <input type="checkbox" name="n" value=1 /> <input type="checkbox" name="n" value=2 /> <input type="checkbox" name="n" value=3 /> ``` When submitted, it will comma delimit all values to the request item "n".. so Request["n"] == "1,2,3" if all three are checked when submitted. In ASP.NET MVC, you can have a parameter of n as an array to accept this post. ``` public ActionResult ActionName( int[] n ) { ... } ``` All of the above works fine. The problem I have is that when validation fails, the check boxes are not restored to their checked state. Any suggestions. Problem Code: (I started with the default asp.net mvc project) Controller ``` public class HomeController : Controller { public ActionResult Index() { var t = getTestModel("First"); return View(t); } [AcceptVerbs(HttpVerbs.Post)] public ActionResult Index(TestModelView t) { if(String.IsNullOrEmpty( t.TextBoxValue)) ModelState.AddModelError("TextBoxValue", "TextBoxValue required."); var newView = getTestModel("Next"); return View(newView); } private TestModelView getTestModel(string prefix) { var t = new TestModelView(); t.Checkboxes = new List<CheckboxInfo>() { new CheckboxInfo(){Text = prefix + "1", Value="1", IsChecked=false}, new CheckboxInfo(){Text = prefix + "2", Value="2", IsChecked=false} }; return t; } } public class TestModelView { public string TextBoxValue { get; set; } public List<CheckboxInfo> Checkboxes { get; set; } } public class CheckboxInfo { public string Text { get; set; } public string Value { get; set; } public bool IsChecked { get; set; } } } ``` ASPX ``` <% using( Html.BeginForm() ){ %> <p><%= Html.ValidationSummary() %></p> <p><%= Html.TextBox("TextBoxValue")%></p> <p><% int i = 0; foreach (var cb in Model.Checkboxes) { %> <input type="checkbox" name="Checkboxes[<%=i%>]" value="<%= Html.Encode(cb.Value) %>" <%=cb.IsChecked ? "checked=\"checked\"" : String.Empty %> /><%= Html.Encode(cb.Text)%><br /> <% i++; } %></p> <p><input type="submit" value="submit" /></p> <% } %> ``` Working Code Controller ``` [AcceptVerbs(HttpVerbs.Post)] public ActionResult Index(TestModelView t) { if(String.IsNullOrEmpty( t.TextBoxValue)) { ModelState.AddModelError("TextBoxValue", "TextBoxValue required."); return View(t); } var newView = getTestModel("Next"); return View(newView); } ``` ASPX ``` int i = 0; foreach (var cb in Model.Checkboxes) { %> <input type="checkbox" name="Checkboxes[<%=i%>].IsChecked" <%=cb.IsChecked ? "checked=\"checked\"" : String.Empty %> value="true" /> <input type="hidden" name="Checkboxes[<%=i%>].IsChecked" value="false" /> <input type="hidden" name="Checkboxes[<%=i%>].Value" value="<%= cb.Value %>" /> <input type="hidden" name="Checkboxes[<%=i%>].Text" value="<%= cb.Text %>" /> <%= Html.Encode(cb.Text)%><br /> <% i++; } %></p> <p><input type="submit" value="submit" /></p> ``` Of course something similar could be done with Html Helpers, but this works.