在asp.net mvc中，Dropdownlist值总是返回零。

This is the sample of the model class

这是model类的示例

[Required(ErrorMessage = "Department is required")]
[Display(Name = "Department")]
public int SelectedValue { get; set; }


[Required(ErrorMessage = "Department is required")]
[Display(Name = "Department")]
public List<Department> RoleList { get; set; }

This is the view

这是

<div class="col-md-10">
    @Html.DropDownListFor(m => m.RoleList, new SelectList(Model.RoleList,"ID", "RoleName","1"), "Please Choose a Department", new { htmlAttributes = new { @class = "form-control"} })
    @Html.ValidationMessageFor(model => model.SelectedValue, "",new { @class = "text-danger"})
</div>

The list is populated perfectly from the database. Now when i select the item on the list, the select value has to be sent to the controller

该列表从数据库中完美地填充。现在，当我在列表中选择项目时，必须将选择值发送给控制器。

public async Task<ActionResult> Register(RegisterViewModel model)
{
    int Selectedvalue = model.SelectedValue;
    if (ModelState.IsValid && (model.SelectedValue).ToString() != "0")
    {

Here i have made a selection

这里我做了一个选择

Error

错误

1 个解决方案

#1

You should change it

你应该改变它

@Html.DropDownListFor(m => m.RoleList, new SelectList(Model.RoleList,"ID", "RoleName","1"), "Please Choose a Department", new { htmlAttributes = new { @class = "form-control"} })

来

@Html.DropDownListFor(m => m.SelectedValue, new SelectList(Model.RoleList,"ID", "RoleName","1"), "Please Choose a Department", new { htmlAttributes = new { @class = "form-control"} })

The first parameter of the DropDownListFor should be selected value in model. In your case, this property is Model.SelectedValue not Model.RoleList.

DropDownListFor的第一个参数应该在模型中选择值。在您的例子中，这个属性是Model。SelectedValue Model.RoleList。

#1