我有以下 ViewModel；
public class MyViewModel {
[Required(ErrorMessage = "Location is required")]
[Range(SOME_RANDOM_COORDINATE, SOME_RANDOM_COORDINATE, ErrorMessage = "Keep location within map bounds")]
public double? Latitude { get; set; }
[Required(ErrorMessage = "Location is required")]
[Range(SOME_RANDOM_COORDINATE, SOME_RANDOM_COORDINATE, ErrorMessage = "Keep location within map bounds")]
public double? Longitude { get; set; }
}
我使用 OpenStreetMap 作为这些纬度和经度值的输入，并且我想使用 ViewModel 中的属性添加客户端和服务器端验证。我正在创建两个 html 输入字段（都隐藏）。当提交表单（而不是设置位置）时，我自然会收到两次“需要位置”的信息。如何将这两个属性组合在一起进行验证？
看法;
<form asp-area="" asp-controller="Report" asp-action="Create" method="post" enctype="multipart/form-data">
<h4>@ViewData["Title"]</h4>
<hr />
<div class="form-group">
<input id="latitude" type="hidden" asp-for="@Model.Latitude" class="form-control" />
<span asp-validation-for="@Model.Latitude" class="text-danger"></span>
</div>
<div class="form-group">
<input id="longitude" type="hidden" asp-for="@Model.Longitude" class="form-control" />
<span asp-validation-for="@Model.Longitude" class="text-danger"></span>
</div>
</form>
您可以尝试使用自定义属性来验证坐标对。
在您的模型中，我将删除 [Required] 属性并将其替换为自定义验证属性。这些值可以设置为模型中的默认值，以便初始视图最初不会抛出错误。然后，您的控制器可以在呈现视图后将坐标覆盖为您想要的任何内容。
public class MyCoordinateModel {
[Range(SOME_RANDOM_COORDINATE, SOME_RANDOM_COORDINATE, ErrorMessage = "Keep location within map bounds")]
[CustomCoordinate("Longitude", ErrorMessage = "{0} field has not been set.")]
public double? Latitude { get; set; }
[Range(SOME_RANDOM_COORDINATE, SOME_RANDOM_COORDINATE, ErrorMessage = "Keep location within map bounds")]
[CustomCoordinate("Latitude", ErrorMessage = "{0} field has not been set.")]
public double? Longitude { get; set; }
MyCoordinateModel()
{
Longitude = 0;
Latitude = 0;
}
}
自定义属性将是这样的，错误消息有条件地显示为无效的属性：
[AttributeUsage(AttributeTargets.Property |
AttributeTargets.Field, AllowMultiple = false)]
public class CustomCoordinateAttribute : ValidationAttribute
{
private readonly string _requiredProperty;
public CustomCoordinateAttribute(public double? requiredValue)
{
_requiredProperty = requiredValue;
}
protected override ValidationResult IsValid(object value,
ValidationContext validationContext)
{
var currentValue = (double)value;
var property =
validationContext.ObjectType.GetProperty(_requiredProperty);
if (property == null)
throw new ArgumentException("Specified property name not found");
var otherValue =
(DateTime)property.GetValue(validationContext.ObjectInstance);
if ((currentValue == null) || (otherValue == null))
{
return new ValidationResult("None of the coordinates are defined");
}
if ((currentValue == null) && (otherValue != null))
{
return new ValidationResult(String.Format(
ErrorMessageString, currentValue));
}
if ((currentValue != null) && (otherValue == null))
{
return new ValidationResult(String.Format(
ErrorMessageString, otherValue);
}
if ((currentValue < 0) || (otherValue < 0))
{
return new ValidationResult("Coordinates cannot be negative");
}
return ValidationResult.Success;
}
}
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