如何绑定下拉列表以使用viewdata [英] How to bind dropdown list for using viewdata

问题描述

我在我看来写了以下代码。

I have written following code in my view.

<pre lang="c#">
<%Html.DropDownListFor("ddlCity",new SelectList(ViewData["City"].ToString(),"Value","Text"));%>

以及控制器中的以下代码

and following code in the controller

<pre lang="c#">

 public ActionResult Index()
        {
            DbConnect objdb = new DbConnect();
            DataTable dt= objdb.ExecuteDataset("usp_allCities");
           
            
            List<SelectListItem> cityList=new List<SelectListItem>();
            
           
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                cityList.Add(new SelectListItem { Text = dt.Rows[i]["CityName"].ToString(), Value = dt.Rows[i]["CityId"].ToString() });
            }
           
            ViewData["City"] = (IEnumerable<SelectListItem>)cityList;
                return View(ViewData);
        }

我无法绑定下拉列表。任何人都可以建议我该怎么做？

浏览器给出以下错误 -

CS0411：方法'System.Web.Mvc.Html.SelectExtensions.DropDownListFor<的类型参数; tmodel，tproperty>（System.Web.Mvc.HtmlHelper< tmodel>，System.Linq.Expressions.Expression< system.func>< tmodel，tproperty>>，System.Collections.Generic.IEnumerable< system.web。 mvc.selectlistitem>）'无法从使用中推断出来。尝试明确指定类型参数。

I am not able to bind the dropdown list. Can any one suggest me what can i do?
Browser gives following error -
CS0411: The type arguments for method 'System.Web.Mvc.Html.SelectExtensions.DropDownListFor<tmodel,tproperty>(System.Web.Mvc.HtmlHelper<tmodel>, System.Linq.Expressions.Expression<system.func><tmodel,tproperty>>, System.Collections.Generic.IEnumerable<system.web.mvc.selectlistitem>)' cannot be inferred from the usage. Try specifying the type arguments explicitly.

推荐答案

尝试使用@ Html.DropDownList而不是DropDownListfor



您不能使用Helper @ Html.DropdownListFor，因为第一个参数不正确将您的助手更改为：

Try using @Html.DropDownList instead DropDownListfor

You cannot used that Helper @Html.DropdownListFor, because the first parameters was not correct change your helper to:

@Html.DropDownList("accountid", new SelectList(ViewBag.Accounts, "AccountID", "AccountName"))

@ Html.DropDownListFor在第一个参数中接收一个lambda所有重载中的表达式用于创建强类型下拉菜单



如果您对某些模型强烈键入View，则可以使用帮助程序更改代码以创建强类型下拉列表，类似

@Html.DropDownListFor receive in the first parameters a lambda expression in all overloads and is used to create strongly typed dropdowns

If your View it's strongly typed to some Model you may change your code using a helper to created a strongly typed dropdownlist, something like

@Html.DropDownListFor(x => x.accountId, new SelectList(ViewBag.Accounts, "AccountID", "AccountName"))

这是文档



; _）

Here is Documentation

;_)

以正常方式设置ViewData，分配一个映射到模型中将绑定在Post上的属性的键名。

Set up your ViewData in the normal way, assigning a Key name that maps to a property in your model that will be bound on Post .

ViewData["ModelPropertyName"] = new SelectList(...)

然后在你的视图中添加一个Html.DropDownList ...

Then in your view simply add a Html.DropDownList ...

@Html.DropDownList("ModelPropertyName")

快乐编码; - ）

Happy coding ;-)

试试这个..

try this..

@Html.DropDownList("Select", new SelectList((System.Collections.IEnumerable)ViewData["list"], "Id", "Name"))

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