/// <summary>
/// Returns a table with checkbox options for a model property
/// </summary>
/// <param name="htmlHelper">The HTML helper instance that this method extends.</param>
/// <param name="expression">An expression that contains the property to render</param>
/// <param name="selectList">A collection of SelectListItem objects that are used to populate the drop-down list</param>
/// <param name="attributes">Personalized attributes to set on table</param>
public static MvcHtmlString CheckBoxTableFor <TModel, TProperty>(this HtmlHelper <TModel> htmlHelper, Expression <Func <TModel, TProperty> > expression, IEnumerable <SelectListItem> selectList, AttributesTable attributes)
{
var tableBody = new TagBuilder("tbody");
attributes = CreateTableContent(ref tableBody, selectList, attributes);
return(MvcHtmlString.Create(CreateBaseTable(tableBody, attributes).ToString(TagRenderMode.Normal)));
}
//para criar a estrutura principal da tabela (cria theader e junta tbody):
private static TagBuilder CreateBaseTable(TagBuilder tableBody, AttributesTable attributes)
{
return(CreateBaseTable(tableBody, attributes, null));
}
//para criar o conteudo da tabela (tbody):
private static AttributesTable CreateTableContent(ref TagBuilder tableBody, IEnumerable <SelectListItem> selectList, AttributesTable attributes)
{
//criação de selectList com os dados a expor na tabela:
var newList = new SelectList(selectList, "Id", (selectList as MultiSelectList).DataTextField);
var selectedValues = (selectList as SelectList).SelectedValue as ICollection;
if (selectedValues != null)
{
newList = new SelectList(selectedValues, "Id", (selectList as MultiSelectList).DataTextField);
}
if (selectList != null)
{
int index = 0, countSelected = 0;
foreach (var item in selectList)
{
try
{
//verifica se o item conincide com os itens selecionados no model:
foreach (var selectedItem in from object selectedItem in selectedValues let valor = selectedItem.getPropertyValue((selectList as MultiSelectList).DataTextField) where selectedItem.getPropertyValue((selectList as MultiSelectList).DataTextField).ToString() == item.Text select selectedItem)
{
item.Selected = true;
if (attributes.isBackoffice)
{
item.Selected = bool.Parse(selectedItem.getPropertyValue("Selected").ToString().ToLower());
}
break;
}
}
catch (Exception) {}
//criação de nova linha da tabela:
var newTR = new TagBuilder("tr");
newTR.MergeAttribute("id", index.ToString());
newTR.AddCssClass(index % 2 == 0 ? "odd" : "even");
//criação de checkbox a apresentar na tabela:
var checkbox = new TagBuilder("input");
checkbox.MergeAttribute("type", "checkbox");
if (attributes.isBackoffice)
{
checkbox.MergeAttribute("data-fieldname", "Selected");
}
if (attributes.AllChecked)
{
checkbox.MergeAttribute("value", "true");
checkbox.MergeAttribute("checked", "true");
}
else
{
checkbox.MergeAttribute("value", item.Selected.ToString().ToLower());
checkbox.MergeAttribute("checked", item.Selected.ToString().ToLower());
}
//à tabela são também adicionados campos (hidden) referentes ao Id da propriedade e à sua descrição:
var hiddenId = new TagBuilder("input");
hiddenId.MergeAttribute("type", "hidden");
hiddenId.MergeAttribute("value", item.Value);
hiddenId.MergeAttribute("id", "isId");
hiddenId.MergeAttribute("data-fieldname", String.IsNullOrEmpty(attributes.IdName) ? (selectList as MultiSelectList).DataValueField : attributes.IdName);
var hiddenDesc = new TagBuilder("input");
hiddenDesc.MergeAttribute("type", "hidden");
hiddenDesc.MergeAttribute("value", item.Text);
hiddenDesc.MergeAttribute("id", "isName");
hiddenDesc.MergeAttribute("data-fieldname", (selectList as MultiSelectList).DataTextField);
//atualização dos campos a inserir na tabela, ou seja, caso no model esses valores estejam selecionados, esse facto deve-se verifica visualmente e no momento de submissão dos dados:
if (selectedValues != null && selectedValues.Count != 0)
{
if (newList.Any(selectedItem => (String.IsNullOrEmpty(selectedItem.Text) && selectedItem.Value == item.Value) || (!String.IsNullOrEmpty(selectedItem.Text) && selectedItem.Text == item.Text && item.Selected)))
{
checkbox.MergeAttribute("value", "true");
checkbox.MergeAttribute("checked", "true");
if (!String.IsNullOrEmpty(attributes.FieldName))
{
//para os valores chegarem realmente selecionados ao controller deve-se garantir isso definindo o nome da coleção, o indice do objeto e o nome e valor de cada propriedade:
if (attributes.isBackoffice)
{
checkbox.MergeAttribute("name", attributes.FieldName + "[" + countSelected + "].Selected"); // para desaparecer no futuro
}
hiddenId.MergeAttribute("name", attributes.FieldName + "[" + countSelected + "]." + (String.IsNullOrEmpty(attributes.IdName) ? (selectList as MultiSelectList).DataValueField : attributes.IdName));
hiddenDesc.MergeAttribute("name", attributes.FieldName + "[" + countSelected + "]." + (selectList as MultiSelectList).DataTextField);
}
countSelected++;
}
}
//adiciona-se todos os campos aos respetivos TDs, adicionam-se os TDs à nova linha criada, e adiciona-se a linha ao tbody da tabela:
newTR.InnerHtml += "<td>" + hiddenId + hiddenDesc + checkbox + "</td><td>" + item.Text + "</td>";
tableBody.InnerHtml += newTR;
index++;
}
if (index == countSelected && countSelected != 0)
{
attributes.AllChecked = true;
}
}
return(attributes);
}
