验证和编辑Asp.net MVC 3中的“changeable_optional”类型
本文关键字：changeable optional 类型 中的 编辑 Asp net MVC 验证 | 更新日期: 2023-09-27 18:13:35
对于一个项目，我需要一种方法来指定属性是否已经更改。
所以在一个模型中，我想要这样做:
public class Changeable<T>
{
public bool Changed { get; set; }
public T Value { get; set; }
}
public class MyModel
{
[Range(1, 10)]
public Changeable<int> SomeInt { get; set; }
}
视图:
@Html.EditorFor(model => model.SomeInt)
然后我将生成一个带有文本字段(int)和复选框(已更改)的编辑器。验证属性(Range等)应该在复选框被选中时调用，而不是在未选中时调用。
我曾试图用Changeable的编辑器模板(然后是验证，模型绑定等)，但我已经失去了编辑器模板，因为它不能是通用的。
我想要的解决方案是可能的，还是有另一个合理的优雅的解决方案?
现在我正在开发一个解决方案与属性string[] ChangedProperties和很多Javascript来处理验证等，但它是相当丑陋和远未完成。
谢谢…
您可以尝试使用带有自定义范围验证属性的动态类型:
public interface IChangeable
{
bool Changed { get; set; }
}
public class Changeable<T> : IChangeable
{
public bool Changed { get; set; }
public T Value { get; set; }
}
public class MyModel
{
[MyRange(1, 10)]
public Changeable<int> SomeInt { get; set; }
}
public class MyRangeAttribute : RangeAttribute
{
public MyRangeAttribute(double minimum, double maximum): base(minimum, maximum)
{ }
public MyRangeAttribute(int minimum, int maximum)
: base(minimum, maximum)
{ }
public override bool IsValid(object value)
{
var changeable = value as IChangeable;
if (changeable == null || !changeable.Changed)
{
return true;
}
dynamic dynValue = value;
return base.IsValid((object)dynValue.Value);
}
}
then a controller:
public class HomeController : Controller
{
public ActionResult Index()
{
return View(new MyModel
{
SomeInt = new Changeable<int>
{
Changed = true,
Value = 5
}
});
}
[HttpPost]
public ActionResult Index(MyModel model)
{
return View(model);
}
}
then a view (~/Views/Home/Index.cshtml):
@model MyModel
@using (Html.BeginForm())
{
@Html.EditorFor(x => x.SomeInt)
<button type="submit">OK</button>
}
和相应的编辑器模板(注意编辑器模板文件的名称)
~/Views/Shared/EditorTemplates/Changeable`1.cshtml
@model dynamic
@Html.CheckBox("Changed", (bool)Model.Changed)
@Html.Editor("Value")
@Html.ValidationMessage("")
我被这个问题迷住了，我花了相当多的时间思考你的目标。我昨天有了一个突破，我有一些代码可以完成你几乎所有的目标。
您已经说过，您希望验证器仅在选中Changed时触发。这段代码总是触发验证器，因为我不认为阻止验证器触发是一个好的实践。代码所做的是检查用户是否更改了值，当发生这种情况时，它会自动检查Changed。如果用户取消选中"已更改"复选框，则旧值将放在Value框中。
代码由一个HTML helper、一个ModelMetadataProvider、一个ModelBinder和一小段javascript组成。在代码之前，这里是已定义的模型，它与Darin的模型相同，只是添加了一个额外的属性:
public interface IChangeable
{
bool Changed { get; set; }
}
public class Changeable<T> : IChangeable
{
public bool Changed { get; set; }
public T Value { get; set; }
}
public class MyModel
{
[Range(1, 10), Display(Name = "Some Integer")]
public Changeable<int> SomeInt { get; set; }
[StringLength(32, MinimumLength = 6), Display(Name = "This String")]
public Changeable<string> TheString { get; set; }
}
从HTML帮助器开始:
public static class HtmlHelperExtensions
{
public static MvcHtmlString ChangeableFor<TModel, TValue, TType>(this HtmlHelper<TModel> html, Expression<Func<TModel, TValue>> expression, Changeable<TType> changeable)
{
var name = ExpressionHelper.GetExpressionText(expression);
if (String.IsNullOrEmpty(name))
throw new ArgumentNullException("name", "Name cannot be null");
var metadata = ModelMetadata.FromLambdaExpression(expression, html.ViewData);
var type = metadata.ModelType;
var containerType = metadata.ContainerType;
var arg = Expression.Parameter(containerType, "x");
Expression expr = arg;
expr = Expression.Property(expr, name);
expr = Expression.Property(expr, "Value");
var funcExpr = Expression.Lambda(expr, arg) as Expression<Func<TModel, TType>>;
var valueModelMetadata = ModelMetadata.FromLambdaExpression(funcExpr, html.ViewData);
Expression exprChanged = arg;
exprChanged = Expression.Property(exprChanged, name);
exprChanged = Expression.Property(exprChanged, "Changed");
var funcExprChanged = Expression.Lambda(exprChanged, arg) as Expression<Func<TModel, bool>>;
var htmlSb = new StringBuilder("'n");
htmlSb.Append(LabelExtensions.Label(html, metadata.GetDisplayName()));
htmlSb.Append("<br />'n");
htmlSb.Append(InputExtensions.CheckBoxFor(html, funcExprChanged));
htmlSb.Append(" Changed<br />'n");
htmlSb.Append(InputExtensions.Hidden(html, name + ".OldValue", valueModelMetadata.Model) + "'n");
htmlSb.Append(EditorExtensions.EditorFor(html, funcExpr, new KeyValuePair<string, object>("parentMetadata", metadata)));
htmlSb.Append(ValidationExtensions.ValidationMessageFor(html, funcExpr));
htmlSb.Append("<br />'n");
return new MvcHtmlString(htmlSb.ToString());
}
}
这将父元数据传递给ViewData(这将允许我们稍后获得类验证器)。它还创建lambda表达式，因此我们可以使用CheckBoxFor()和EditorFor()。使用我们的模型和这个助手的视图如下:
@model MyModel
@{
ViewBag.Title = "Index";
Layout = "~/Views/Shared/_Layout.cshtml";
}
@using (Html.BeginForm())
{
<script type="text/javascript">
$(document).ready(function () {
$("input[id$='Value']").live("keyup blur", function () {
var prefix = this.id.split("_")[0];
var oldValue = $("#" + prefix + "_OldValue").val();
var changed = oldValue != $(this).val()
$("#" + prefix + "_Changed").attr("checked", changed);
if (changed) {
// validate
$(this.form).validate().element($("#" + prefix + "_Value")[0]);
}
});
$("input[id$='Changed']").live("click", function () {
if (!this.checked) {
// replace value with old value
var prefix = this.id.split("_")[0];
var oldValue = $("#" + prefix + "_OldValue").val();
$("#" + prefix + "_Value").val(oldValue);
// validate
$(this.form).validate().element($("#" + prefix + "_Value")[0]);
}
});
});
</script>
@Html.ChangeableFor(x => x.SomeInt, Model.SomeInt)
@Html.ChangeableFor(x => x.TheString, Model.TheString)
<input type="submit" value="Submit" />
}
注意处理Value文本框更改和单击Changed复选框的javascript。还要注意需要将Changeable<T>属性两次传递给ChangeableFor()帮助器。
public class MyDataAnnotationsModelValidatorProvider : DataAnnotationsModelValidatorProvider
{
private bool _provideParentValidators = false;
protected override IEnumerable<ModelValidator> GetValidators(ModelMetadata metadata, ControllerContext context, IEnumerable<Attribute> attributes)
{
if (metadata.ContainerType != null && metadata.ContainerType.Name.IndexOf("Changeable") > -1 && metadata.PropertyName == "Value")
{
var viewContext = context as ViewContext;
if (viewContext != null)
{
var viewData = viewContext.ViewData;
var index = viewData.Keys.ToList().IndexOf("Value");
var parentMetadata = viewData.Values.ToList()[index] as ModelMetadata;
_provideParentValidators = true;
var vals = base.GetValidators(parentMetadata, context);
_provideParentValidators = false;
return vals;
}
else
{
var viewData = context.Controller.ViewData;
var keyName = viewData.ModelState.Keys.ToList().Last().Split(new string[] { "." }, StringSplitOptions.None).First();
var index = viewData.Keys.ToList().IndexOf(keyName);
var parentMetadata = viewData.Values.ToList()[index] as ModelMetadata;
parentMetadata.Model = metadata.Model;
_provideParentValidators = true;
var vals = base.GetValidators(parentMetadata, context);
_provideParentValidators = false;
return vals;
}
}
else if (metadata.ModelType.Name.IndexOf("Changeable") > -1 && !_provideParentValidators)
{
// DO NOT provide parent's validators, unless it is at the request of the child Value property
return new List<ModelValidator>();
}
return base.GetValidators(metadata, context, attributes).ToList();
}
}
请注意，检查父元数据有不同的方法，这取决于我们是在填充视图还是在POST上绑定模型。还要注意，我们需要禁止父节点接收验证器。
最后，ModelBinder:public class ChangeableModelBinder : DefaultModelBinder
{
public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
if (controllerContext.Controller.ViewData.Keys.ToList().IndexOf(bindingContext.ModelName) < 0)
controllerContext.Controller.ViewData.Add(bindingContext.ModelName, bindingContext.ModelMetadata);
return base.BindModel(controllerContext, bindingContext);
}
}
这会获取父元数据，并将其隐藏起来，以便稍后在自定义ModelValidatorProvider中访问。
在Global.asax.cs的Application_Start中完成以下内容:
ModelValidatorProviders.Providers.Clear();
ModelValidatorProviders.Providers.Add(new MvcApplication5.Extensions.MyDataAnnotationsModelValidatorProvider());
MyDataAnnotationsModelValidatorProvider.AddImplicitRequiredAttributeForValueTypes = false;
ModelBinders.Binders.Add(typeof(MvcApplication5.Controllers.Changeable<int>), new ChangeableModelBinder());
ModelBinders.Binders.Add(typeof(MvcApplication5.Controllers.Changeable<string>), new ChangeableModelBinder());
// you must add a ModelBinders.Binders.Add() declaration for each type T you
// will use in your Changeable<T>
紫百合!
我不是百分之百确定，但我认为你想要的是:
private int _changeable;
public Changeable<int> SomeInt {
get
{ return _changeable }
set
{ _changeable = value;
Changed = true;
}
}