在MVC中基于模型属性禁用enable dropdownlistfor [英] Disable enable dropdownlistfor based on model property in mvc

问题描述

我正在尝试基于模型属性在我的mvc应用程序中禁用或启用dropdownlistfor:-

I am trying to disable or enable a dropdownlistfor in my mvc application based on model property:-

我正在做的是:-

@Html.DropDownListFor(m => m.ParentOrganisationID, new SelectList(Model.ParentOrganisations, "ID", "Name", Model.ParentOrganisationID), new { @id = "ddlParentOrganisations", @class = "form-control css-select", @disabled = Model.IsReadOnly ? "disabled" : "false", @style = "width:40%; height:10%;" })

但是即使模型属性"model.IsReadOnly"为假，也将下拉列表显示为已禁用.

but even if model property "model.IsReadOnly" is false, then also it is showing the dropdown as disabled.

请建议如何解决此问题，而不使用任何javascript

Please suggest how to handle this, without using any javascript

预先感谢

推荐答案

由于无法传递行，因此无法在调用DropDownListFor helper方法的条件中包含条件(如果/三元语句) C#代码(带有if条件)，它期望html属性的对象.此外，以下所有标记都会呈现一个禁用的SELECT.

It is not possible to include the condition (if/ternary statement(s)) inside the call to the DropDownListFor helper method because you cannot pass a line of c# code (with your if condition) where it expects an object for html attributes. Also all of the below markups will render a disabled SELECT.

<select disabled></select>
<select disabled="disabled"></select>
<select disabled="false"></select>
<select disabled="no"></select>
<select disabled="usingJqueryEnablePlugin"></select>
<select disabled="enabled"></select>

您可以简单地使用if条件检查Model属性的值，并有条件地呈现禁用的版本.

You can simply check the value of your Model property with an if condition and conditionally render the disabled version.

@if (!Model.IsReadOnly)
{
    @Html.DropDownListFor(s => s.ParentOrganisationID, 
                               new SelectList(Model.ParentOrganisations, "ID", "Name"))
}
else
{
    @Html.DropDownListFor(s => s.ParentOrganisationID, 
       new SelectList(Model.ParentOrganisations, "ID", "Name"),new {disabled="disabled"})
}

您可以考虑创建一个自定义的html helper方法，该方法负责if条件检查.

public static class DropDownHelper
{
    public static MvcHtmlString MyDropDownListFor<TModel, TProperty>
                 (this HtmlHelper<TModel> htmlHelper, 
                  Expression<Func<TModel, TProperty>> expression,
                  IEnumerable<SelectListItem> selectItems,
                  object htmlAttributes,
                  bool isDisabled = false)
    {
        ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression,
                                                                    htmlHelper.ViewData);

        IEnumerable<SelectListItem> items =
            selectItems.Select(value => new SelectListItem
            {
                Text = value.Text,
                Value = value.Value,
                Selected = value.Equals(metadata.Model)
            });
        var attributes = HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes);
        if (isDisabled && !attributes.ContainsKey("disabled"))
        {
             attributes.Add("disabled", "disabled");
        }
        return htmlHelper.DropDownListFor(expression,items, attributes);
    }
}

现在在您的剃刀视图中，将此助手称为

Now in your razor view,call this helper

@Html.MyDropDownListFor(s=>s.ParentOrganisationID,
               new SelectList(Model.ParentOrganisations, "ID", "Name")
                                           ,new { @class="myClass"},Model.IsReadOnly)

这篇关于在MVC中基于模型属性禁用enable dropdownlistfor的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！