我试图弄清楚为什么返回带有模型的View时属性值不持久。
Index.cshtml
查看：
@Html.HiddenFor(model => model.IsWtv)
控制器：
[HttpPost]
public ActionResult Index([Bind(Exclude = "Id,ShippingCost")] TestModels model)
{
//assume the initial value is false. I only want it to switch to true once
if (!model.IsWtv)
model.IsWtv = true;
return View(model);
}
型号：
public Boolean IsWtv
{
get;
set;
}
当我重新提交表单时，IsWtv的值始终为false。我不明白为什么？
答案 0 :(得分：1)
首先，在处理控制器操作方法时（除非这是某种类型的AJAX请求），您实际上应该遵循PRG模式（POST，重定向，GET）。
也就是说，class Program
{
static void Main(string[] args)
{
try
{
CustomRuleRepository repository = new CustomRuleRepository();
List<RuleEngineEntity> rules = new List<RuleEngineEntity>();
rules.Add(new RuleEngineEntity { FieldName = "Age", Name = "CustomerCheck", Value = 20 });
repository.LoadRules(rules);
//Compile rules
var factory = repository.Compile();
//Create a working session
var session = factory.CreateSession();
RuleEngineRequestModel ruleEngineRequestModel = new RuleEngineRequestModel { ruleList = rules, customerData = new Customer { Name = "A", Age = 24 } };
session.Insert(ruleEngineRequestModel);
var IspassedorNot = session.Fire();
}
catch (Exception e) {
Console.WriteLine(e.Message);
}
}
}
public class RuleEngineRequestModel
{
public List<RuleEngineEntity> ruleList { get; set; }
public Customer customerData { get; set; }
}
public class RuleEngineEntity
{
public string Name { get; set; }
public int Value { get; set; }
public string Operator { get; set; }
public string FieldName { get; set; }
}
public class Customer
{
public string Name { get; set; }
public int Age { get; set; }
}
public class CustomRuleRepository : IRuleRepository
{
private readonly IRuleSet _ruleSet = new RuleSet("customerRule");
public IEnumerable<IRuleSet> GetRuleSets()
{
return new[] {_ruleSet};
}
public void LoadRules(List<RuleEngineEntity> list)
{
_ruleSet.Add(
BuildRule(list)
);
}
public List<IRuleDefinition> BuildRule(List<RuleEngineEntity> list)
{
NRules.RuleModel.Builders.RuleBuilder builder = null;
List<IRuleDefinition> rulesList = new List<IRuleDefinition>();
builder = new NRules.RuleModel.Builders.RuleBuilder();
builder.Name("CustomerDetail");
ParameterExpression customerParameter = null;
LambdaExpression customerCondition = null;
PatternBuilder customerPattern = null;
try
{
var orGroup = builder.LeftHandSide().Group(GroupType.Or);
foreach (var item in list)
{
var andGroup = orGroup.Group(GroupType.And);
customerPattern = andGroup.Pattern(typeof(RuleEngineRequestModel), item.Name);
customerParameter = customerPattern.Declaration.ToParameterExpression();
customerCondition =
Expression.Lambda(
Expression.GreaterThan(CreateParameterExpression(typeof(RuleEngineRequestModel), "customerData", typeof(Customer), item.FieldName),
Expression.Constant(item.Value)), customerParameter);
customerPattern.Condition(customerCondition);
}
Expression<Action<IContext>> action =
(ctx) => Console.WriteLine("Action triggered");
builder.RightHandSide().Action(action);
rulesList.Add(builder.Build());
}
catch (Exception e)
{
}
return rulesList;
}
public Expression CreateParameterExpression(Type type, string propertyName, Type type2, string propertyName2)
{
ParameterExpression pe = Expression.Parameter(type, "e");
Expression left = Expression.Property(pe, type.GetProperty(propertyName));
return Expression.Property(left, type2.GetProperty(propertyName2));
}
}
是从模型状态而不是模型中获取模型值的，而在更新并返回模型时。为了更新并返回模型，请在进行任何属性修改之前在您的post方法中添加以下代码行：
HtmlHelpers或者您可以在ModelState本身中设置IsWtv的值：
ModelState.Clear();