经常需要对用户输入的数据在插入数据库或者判断之前做Trim处理,针对每个ViewModel的字段各自做处理是我们一般的想法。近调查发现其实也可以一次性实现的。
  MVC4.6中实现方式
  1,实现IModelBinder接口,创建自定义ModelBinder。  
  public class TrimModelBinder : IModelBinder
  {
  public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
  {
  var valueResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
  string attemptedValue = valueResult?.AttemptedValue;
  return string.IsNullOrWhiteSpace(attemptedValue) ? attemptedValue : attemptedValue.Trim();
  }
  }
  2,添加ModelBinder到MVC的绑定库。
  protected void Application_Start()
  {
  //System.Web.Mvc.ModelBinders.Binders.DefaultBinder = new ModelBinders.TrimModelBinder();
  System.Web.Mvc.ModelBinders.Binders.Add(typeof(string), new ModelBinders.TrimModelBinder());
  AreaRegistration.RegisterAllAreas();
  FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
  RouteConfig.RegisterRoutes(RouteTable.Routes);
  BundleConfig.RegisterBundles(BundleTable.Bundles);
  }
  3,确认一下效果

  将密码后面的空格做Trim处理,绑定到ViewModel的时候变成1了:

  Asp.net core 1.1 MVC中实现方式
  1,自定义ModelBinder并继承ComplexTypeModelBinder
  public class TrimModelBinder : ComplexTypeModelBinder
  {
  public TrimModelBinder(IDictionary propertyBinders) : base(propertyBinders) { }
  protected override void SetProperty(ModelBindingContext bindingContext, string modelName, ModelMetadata propertyMetadata, ModelBindingResult result)
  {
  var value = result.Model as string;
  result= string.IsNullOrWhiteSpace(value) ? result : ModelBindingResult.Success(value.Trim());
  base.SetProperty(bindingContext, modelName, propertyMetadata, result);
  }
  }
  2,为ModelBinder添加自定义Provider   
  public class TrimModelBinderProvider : IModelBinderProvider
  {
  public IModelBinder GetBinder(ModelBinderProviderContext context)
  {
  if (context.Metadata.IsComplexType && !context.Metadata.IsCollectionType)
  {
  var propertyBinders = new Dictionary();
  for (int i = 0; i < context.Metadata.Properties.Count; i++)
  {
  var property = context.Metadata.Properties[i];
  propertyBinders.Add(property, context.CreateBinder(property));
  }
  return new TrimModelBinder(propertyBinders);
  }
  return null;
  }
  }
  3,将Provider添加到绑定管理库
  services.AddMvc().AddMvcOptions(s =>
  {
  s.ModelBinderProviders[s.ModelBinderProviders.TakeWhile(p => !(p is ComplexTypeModelBinderProvider)).Count()] = new TrimModelBinderProvider();
  });
  4,确认一下效果

  将密码后面的空格做Trim处理,绑定到ViewModel的时候变成1了:

  总结
  是这么简单,为以后做备忘.