MVC Checkbox

本文转自：http://www.cnblogs.com/season2009/archive/2012/09/17/2685007.html

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.

签名：删除冗余的代码最开心，找不到删除的代码最痛苦！