Question

我想知道是否有人可以帮助我。我在变量var_departmentID中有一个值，数据库下拉列表包含可以传递给变量的相同值。我想将下拉列表默认为变量中的值。我试过以下，但它不起作用。没有错误，它只是没有填充下拉列表。

@{var var_dbDepartment = Database.Open("Intranet");
var var_listDepartment = "SELECT Department_ID, Data FROM tbl_Department";
List<SelectListItem> listDepartmentData = new List<SelectListItem>();
bool departmentIsSelected = false;
listDepartmentData.Add(new SelectListItem { Text = "Please Choose...", Value = "0", Selected = true });
foreach(var var_item in var_dbDepartment.Query(var_listDepartment)) {
    if(var_departmentID == var_item.Department_ID.ToString()) {
        bool isSelected = true;
    }
    else {
        bool isSelected = false;
    }

    listDepartmentData.Add(new SelectListItem{Text = var_item.Data, Value = var_item.Department_ID.ToString(), Selected = false});}}
    @Html.DropDownList("Department", listDepartmentData, new { @class = "field", @id="department", @onchange="myFunction()" })

任何人都可以看到问题所在吗？

Answer 1

我会按如下方式重写您的代码：

@{
    var var_dbDepartment = Database.Open("Intranet");
    var var_listDepartment = "SELECT Department_ID, Data FROM tbl_Department";
    var data = var_dbDepartment.Query(var_listDepartment);
    var items = data.Select(i => new SelectListItem{
        Value = i.Department_ID.ToString(),
        Text = i.Data,
        Selected = i.Department_ID.ToString() == var_departmentID ? true : false
    });
}

@Html.DropDownList("Department", "Please Choose...",  items)

要获得更深入的报道，请查看HTML Helpers For Forms In Razor Web Pages。

将变量值传递给数据库下拉列表

1 个答案: