根据Html.TextBoxFor的条件设置禁用属性

Question

我想根据下面的asp.net MVC中的Html.TextBoxFor条件设置disable属性

@Html.TextBoxFor(model => model.ExpireDate, new { style = "width: 70px;", maxlength = "10", id = "expire-date" disabled = (Model.ExpireDate == null ? "disable" : "") })

该助手有两个输出禁用="禁用"或禁用="".两个主题都使文本框禁用.

如果Model.ExpireDate == null,我想禁用文本框,否则我想启用它

Answer 1

有效的方法是:

disabled="disabled"

浏览器也可以接受, disabled=""但我建议你采用第一种方法.

现在我要建议你编写一个自定义HTML帮助程序,以便将这个禁用功能封装到一个可重用的代码段中:

using System;
using System.Linq.Expressions;
using System.Web;
using System.Web.Mvc;
using System.Web.Mvc.Html;
using System.Web.Routing;

public static class HtmlExtensions
{
    public static IHtmlString MyTextBoxFor<TModel, TProperty>(
        this HtmlHelper<TModel> htmlHelper, 
        Expression<Func<TModel, TProperty>> expression, 
        object htmlAttributes, 
        bool disabled
    )
    {
        var attributes = new RouteValueDictionary(htmlAttributes);
        if (disabled)
        {
            attributes["disabled"] = "disabled";
        }
        return htmlHelper.TextBoxFor(expression, attributes);
    }
}

您可以这样使用:

@Html.MyTextBoxFor(
    model => model.ExpireDate, 
    new { 
        style = "width: 70px;", 
        maxlength = "10", 
        id = "expire-date" 
    }, 
    Model.ExpireDate == null
)

你可以为这个助手带来更多智慧:

public static class HtmlExtensions
{
    public static IHtmlString MyTextBoxFor<TModel, TProperty>(
        this HtmlHelper<TModel> htmlHelper,
        Expression<Func<TModel, TProperty>> expression,
        object htmlAttributes
    )
    {
        var attributes = new RouteValueDictionary(htmlAttributes);
        var metaData = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);
        if (metaData.Model == null)
        {
            attributes["disabled"] = "disabled";
        }
        return htmlHelper.TextBoxFor(expression, attributes);
    }
}

所以现在你不再需要指定禁用的条件:

@Html.MyTextBoxFor(
    model => model.ExpireDate, 
    new { 
        style = "width: 70px;", 
        maxlength = "10", 
        id = "expire-date" 
    }
)

Answer 2

实际上,内部行为是将匿名对象转换为字典.所以我在这些场景中所做的就是找一本字典:

@{
  var htmlAttributes = new Dictionary<string, object>
  {
    { "class" , "form-control"},
    { "placeholder", "Why?" }        
  };
  if (Model.IsDisabled)
  {
    htmlAttributes.Add("disabled", "disabled");
  }
}
@Html.EditorFor(m => m.Description, new { htmlAttributes = htmlAttributes })

或者,斯蒂芬在这里评论道:

@Html.EditorFor(m => m.Description,
    Model.IsDisabled ? (object)new { disabled = "disabled" } : (object)new { })

Answer 3

我喜欢达林方法.但快速解决这个问题的方法,

Html.TextBox("Expiry", null, new { style = "width: 70px;", maxlength = "10", id = "expire-date", disabled = "disabled" }).ToString().Replace("disabled=\"disabled\"", (1 == 2 ? "" : "disabled=\"disabled\""))

Answer 4

我使用一些扩展方法实现了它

private const string endFieldPattern = "^(.*?)>";

    public static MvcHtmlString IsDisabled(this MvcHtmlString htmlString, bool disabled)
    {
        string rawString = htmlString.ToString();
        if (disabled)
        {
            rawString = Regex.Replace(rawString, endFieldPattern, "$1 disabled=\"disabled\">");
        }

        return new MvcHtmlString(rawString);
    }

    public static MvcHtmlString IsReadonly(this MvcHtmlString htmlString, bool @readonly)
    {
        string rawString = htmlString.ToString();
        if (@readonly)
        {
            rawString = Regex.Replace(rawString, endFieldPattern, "$1 readonly=\"readonly\">");
        }

        return new MvcHtmlString(rawString);
    }

然后....

@Html.TextBoxFor(model => model.Name, new { @class= "someclass"}).IsDisabled(Model.ExpireDate == null)

Answer 5

我使用的一个简单方法是条件渲染:

@(Model.ExpireDate == null ? 
  @Html.TextBoxFor(m => m.ExpireDate, new { @disabled = "disabled" }) : 
  @Html.TextBoxFor(m => m.ExpireDate)
)

Answer 6

如果您不使用html助手,您可以使用简单的三元表达式,如下所示:

<input name="Field"
       value="@Model.Field" tabindex="0"
       @(Model.IsDisabledField ? "disabled=\"disabled\"" : "")>

Answer 7

这已经晚了,但可能对某些人有所帮助.

我已经扩展了@ DarinDimitrov的答案,允许传递第二个对象,它接受任意数量的布尔html属性等disabled="disabled" checked="checked", selected="selected".

仅当属性值为true时才会呈现属性,其他任何内容和属性都不会呈现.

自定义可重用的HtmlHelper:

public static class HtmlExtensions
{
    public static IHtmlString MyTextBoxFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper,
                                                                Expression<Func<TModel, TProperty>> expression,
                                                                object htmlAttributes,
                                                                object booleanHtmlAttributes)
    {
        var attributes = new RouteValueDictionary(htmlAttributes);

        //Reflect over the properties of the newly added booleanHtmlAttributes object
        foreach (var prop in booleanHtmlAttributes.GetType().GetProperties())
        {
            //Find only the properties that are true and inject into the main attributes.
            //and discard the rest.
            if (ValueIsTrue(prop.GetValue(booleanHtmlAttributes, null)))
            {
                attributes[prop.Name] = prop.Name;
            }                
        }                                

        return htmlHelper.TextBoxFor(expression, attributes);
    }

    private static bool ValueIsTrue(object obj)
    {
        bool res = false;
        try
        {
            res = Convert.ToBoolean(obj);
        }
        catch (FormatException)
        {
            res = false;
        }
        catch(InvalidCastException)
        {
            res = false;
        }
        return res;
    }

}

您可以这样使用:

@Html.MyTextBoxFor(m => Model.Employee.Name
                   , new { @class = "x-large" , placeholder = "Type something…" }
                   , new { disabled = true})

Answer 8

使用RouteValueDictionary解决了这个问题(可以正常工作,因为它基于IDictionary的htmlAttributes)和扩展方法:

public static RouteValueDictionary AddIf(this RouteValueDictionary dict, bool condition, string name, object value)
{
    if (condition) dict.Add(name, value);
    return dict;
}

用法:

@Html.TextBoxFor(m => m.GovId, new RouteValueDictionary(new { @class = "form-control" })
.AddIf(Model.IsEntityFieldsLocked, "disabled", "disabled"))

信用转到/sf/answers/243737861/

Answer 9

如果您不想使用HTML Helper，请看一下我的解决方案

disabled="@(your Expression that returns true or false")"

那个

@{
    bool isManager = (Session["User"] as User).IsManager;
}
<textarea rows="4" name="LetterManagerNotes" disabled="@(!isManager)"></textarea>

我认为更好的方法是检查控制器并将其保存在view（Razor引擎）内部可访问的变量中，以使 the view free from business logic