将 html select 绑定到长 C# 数组

Question

我的问题是当我想在我的 DTO 中将 html select 绑定到 long[] 的属性时，它显示了一个带有 的下拉列表多重 selection 能力。但我希望它处于 non-multiple (single selection) 模式。我的 DTO：

public class CreateSmsPattern
    {
        [Required(ErrorMessage = ValidationMessages.IsRequired)]
        [MaxLength(128, ErrorMessage = ValidationMessages.InvalidLength)]
        public string Name { get; set; }

        [Required(ErrorMessage = ValidationMessages.IsRequired)]
        [Range(1, long.MaxValue, ErrorMessage = ValidationMessages.IsRequired)]
        public long SpecialListId { get; set; }

        [Required(ErrorMessage = ValidationMessages.IsRequired)]
        [MaxLength(5000, ErrorMessage = ValidationMessages.InvalidLength)]
        public string Message { get; set; }

        [Required(ErrorMessage = ValidationMessages.IsRequired)]
        [Range(1, int.MaxValue, ErrorMessage = ValidationMessages.IsRequired)]
        public int ParametersCount { get; set; }

        public long[] ParametersList { get; set; }
    }

和我的前端（请注意用户必须选择 3 次并且每次只能选择 1 个 selection，因为他的 selection 的顺序对我很重要）：

<div class="col-md-4">
    <div class="form-group">
        <label class="control-label" asp-for="Command.ParametersList">Parameters List</label>
        <select class="form-control" asp-for="Command.ParametersList" asp-items='new SelectList(Model.ParametersList, "Id", "Name")'>
            <option value="-1">Choose one...</option>
        </select>
        <span asp-validation-for="Command.ParametersList" class="error"></span>
    </div>
    <div class="form-group">
        <select class="form-control" asp-for="Command.ParametersList" asp-items='new SelectList(Model.ParametersList, "Id", "Name")'>
            <option value="-1">Choose one...</option>
        </select>
        <span asp-validation-for="Command.ParametersList" class="error"></span>
    </div>
    <div class="form-group">
        <select class="form-control" asp-for="Command.ParametersList" asp-items='new SelectList(Model.ParametersList, "Id", "Name")'>
            <option value="-1">Choose one...</option>
        </select>
        <span asp-validation-for="Command.ParametersList" class="error"></span>
    </div>
</div>

Answer 1

如果您需要三个选择，那么您应该为每个选择设置三个接收属性：

public long Selection1 { get; set; }
public long Selection2 { get; set; }
public long Selection3 { get; set; }

并使用您的标签助手定位这些属性：

<div class="form-group">
    <select class="form-control" asp-for="Selection1" asp-items='new SelectList(Model.ParametersList, "Id", "Name")'>
        <option value="-1">Choose one...</option>
    </select>
    <span asp-validation-for="Selection1" class="error"></span>
</div>

<div class="form-group">
    <select class="form-control" asp-for="Selection2" asp-items='new SelectList(Model.ParametersList, "Id", "Name")'>
        <option value="-1">Choose one...</option>
    </select>
    <span asp-validation-for="Selection2" class="error"></span>
</div>

<div class="form-group">
    <select class="form-control" asp-for="Selection3" asp-items='new SelectList(Model.ParametersList, "Id", "Name")'>
        <option value="-1">Choose one...</option>
    </select>
    <span asp-validation-for="Selection3" class="error"></span>
</div>

这样你也不必担心顺序。

将 html select 绑定到长 C# 数组

Bind html select to array of long C#

html

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razor