MVC Checkbox

单个Checkbox

针对single checkbox使用方法和textbox等并没有太大区别, 代码如下:

View:

<%= Html.CheckBoxFor(model => model.IsNeverExpired)%>

HTML生成:

<input id="IsNeverExpired" name="IsNeverExpired" type="checkbox" value="true" />
<input name="IsNeverExpired" type="hidden" value="false" />

Controller:

//创建
public override JsonResult Create(Credential model) { }

//编辑
public override JsonResult Edit(string id, FormCollection formValues)
{
    Credential model = repository.GetByID(Convert.ToInt32(id));
    UpdateModel(model);
}

上面生成的HTML有点奇怪, 为什么它会生成两个控件呢?

因为如果只生成一个input, 系统无法区分"没有选中checkbox" 和 "checkbox没有生成".

那又是为什么只生成一个input就无法区分呢?

原来当一个form中包含checkbox时,如果没有给它赋值(选中), 在服务器端Request.Form中得到的值是NULL

据说是标准的browser behaviour.

参见:http://forums.asp.net/t/1425806.aspx/1/10

多个Checkbox

当对象之间是多对多的关系时, 在数据库中一般是通过建立一个中间表来映射, 如一个证件有多个专业(或一篇文章属于多个Categorie)

此时CheckBox组就派上用场了. 由于并没有类似Html.CheckBoxListFor这样的方法, 我是通过如下方法实现的.

View:

<% foreach (var item in (MultiSelectList)ViewData["list"]) {%>
<input type="checkbox" name="ProfessionalIDs" value="<%=item.Value%>" id="Professional<%=item.Value%>" <%=item.Selected ? "checked=\"checked\"" : String.Empty%> />
    <label for="Professional<%=item.Value%>"><%=item.Text%></label>
<%} %>

Controller:

View Code

public override ActionResult Create()
{
    Credential model = new Credential();
    model.InitProfessionalList();

    ViewData["list"] = new MultiSelectList(model.Professionals.Items, "TypeID", "Name", null);
    return View(model);
}   

[AcceptVerbs(HttpVerbs.Post)]
public override JsonResult Create(Credential model)
{
    if (model.ProfessionalIDs == null)
    {
        model.CredentialProfessional = new System.Data.Linq.EntitySet<CredentialProfessional>();
    }
    else
    {
        foreach (int professionalID in model.ProfessionalIDs)
        {
            model.CredentialProfessional.Add(new CredentialProfessional() { CredentialID = model.CredentialID, ProfessionalID = professionalID });
        }
    }
    ...      
}

[AcceptVerbs(HttpVerbs.Post)]
public override JsonResult Edit(string id, FormCollection formValues)
{
    repository.Edit(model, formValues["ProfessionalIDs"]);
    ...
}

Repository:

View Code

public StatusEnum Add(TEntity entity)
{
    db.GetTable<TEntity>().InsertOnSubmit(entity);
    db.SubmitChanges();
    return StatusEnum.Success;
}

public StatusEnum Edit(Credential model, string professional)
{
    List<CredentialProfessional> newSelect = new List<CredentialProfessional>();

    if (!string.IsNullOrEmpty(professional))
    {
        string[] professionalArray = professional.Split(',');

        foreach (string professionalID in professionalArray)   //新选择的项保存到集合中
        {
            newSelect.Add(new CredentialProfessional() { CredentialID = model.CredentialID, ProfessionalID = Convert.ToInt32(professionalID) });
        }
    }

    model.CredentialProfessional.Except(newSelect).ToList().ForEach(n => db.CredentialProfessional.DeleteOnSubmit(n));
    newSelect.Except(model.CredentialProfessional).ToList().ForEach(n => db.CredentialProfessional.InsertOnSubmit(n));
    db.SubmitChanges();
    return StatusEnum.Success;
}

说明: CredentialProfessional就是中间表, 须以其2个外健做为联合主健.