基础拾遗-----数据注解与验证
前言
其实对于这块知识点，一直觉得没有必要进行总结，只是新到的公司当时用到了 kendo for asp.net mvc ，里面有用到，自动初始化页面，而依据基于对象属性的注解与验证，故此抽时间总计了一下吧。借鉴与《asp.net mvc 5高级编程》
验证注解的使用
数据注解定义在一般在命名空间”System.ComponentModel.DataAnnotations”提供了服务器端验证的功能，当在模型的属性上使用时，框架也支持客户端验证。在命名空间DataAnnotations总工有4个特性可以用于一般的验证场合。
1.Required 强调不能为空
[Required(ErrorMessage = "{0}不能为空")] public Guid BID { get; set; }
2.StringLength控制字段长度
[StringLength(4000, MinimumLength = 1, ErrorMessage = "{0}长度在{2}-{1}之间")] public String Enclosure { get; set; }
3.RegularExpression正则表达式
[RegularExpression(@"^([a-zA-Z0-9_-])+@([a-zA-Z0-9_-])+(.[a-zA-Z0-9_-])+",ErrorMessage = "邮箱输入有误，重新输入。")] public string Email { get; set; }
4.Range指定值类型的范围
[Range(35,44,ErrorMessage = "年龄不符合要求")] public int Age { get; set; }
5.Compare两次输入必须一致
[RegularExpression(@"^([a-zA-Z0-9_-])+@([a-zA-Z0-9_-])+(.[a-zA-Z0-9_-])+",ErrorMessage = "邮箱输入有误，重新输入。")] public string Email { get; set; } [Compare("Email ")] public string Email2 { get; set; }
6.Remote 是mvc框架为应用程序在命名空间system.web.mvc额外添加的可以利用服务器端的回到函数执行客户端的验证逻辑
[Remote("CheckUserName", "Admin")] public string UserName { get; set; }
public JsonResult CheckUserName(string username) { return Json(DateTime.Now.ToString(),JsonRequestBehavior.AllowGet); }
显示和编辑注解
1.DisplayName显示名称
[DisplayName("金额（元）")] public Decimal Money { get; set; }
2.ScaffoldColumn可以隐藏HTML的辅助方法
[ScaffoldColumn(false)] public string UserName { get; set; }
注：虽然ScaffoldColumn可以做到不显示一些属性在页面上被编辑，但是如果提交的Form有这个属性值，模型绑定机制依然会绑定此属性值。
3.DisplayFormat处理属性的各种格式。比如日期，浮点数等
[DisplayFormat(ApplyFormatInEditMode = true,DataFormatString = "{0:c}")] public decimal Total { get; set; }
4.ReadOnly只读
[DisplayName("计取时间")] [ReadOnly(true)] public string RememberTime { get; set; }
5.运行时提供关于属性的特定用途信息。
[Required(ErrorMessage = "密码不能为空")] [DataType(DataType.Password)] public string Password { get; set; }
自定义验证属性
其实这个方法就是定一个特性，进行验证。至于特性前面的文章有涉及。
下面对此的应用如下：
[SelectList("/Inspect/GetSite?all=0", HttpVerbs.Post, CascadeFrom = "SegmentID", DataValueField = "SiteID", DataTextField = "Name", Data = @"function(){ return { segmentId: $(""#SegmentID"").val() }; }", DataType = "DropDownList")] [Required(ErrorMessage = "{0}不能为空")] public Guid SiteID { get; set; }
具体实现如下
[AttributeUsage(AttributeTargets.Property, AllowMultiple=false, Inherited=true)] public class SelectListAttribute : Attribute, IMetadataAware { public SelectListAttribute(string remoteUrl, System.Web.Mvc.HttpVerbs httpVerbs = 1) { if (remoteUrl == null) { throw new ArgumentNullException("remoteUrl"); } this.RemoteUrl = remoteUrl; this.HttpVerbs = httpVerbs; this.ServerFiltering = true; } public void OnMetadataCreated(ModelMetadata metadata) { if (metadata == null) { throw new ArgumentNullException("metadata"); } IDictionary<string, string> dictionary = null; if (!string.IsNullOrEmpty(this.AdditionalValues)) { try { dictionary = this.AdditionalValues.FromJson<IDictionary<string, string>>(); } catch { dictionary = new Dictionary<string, string>(); } if ((dictionary != null) && (dictionary.Count > 0)) { foreach (KeyValuePair<string, string> pair in dictionary) { metadata.AdditionalValues[pair.Key] = pair.Value; } } } metadata.AdditionalValues["RemoteUrl"] = this.RemoteUrl; metadata.AdditionalValues["Type"] = this.HttpVerbs; metadata.AdditionalValues["Data"] = this.Data; metadata.AdditionalValues["ServerFiltering"] = this.ServerFiltering; metadata.AdditionalValues["Events"] = this.ParseEvents(this.Events); metadata.AdditionalValues["CascadeFrom"] = this.CascadeFrom; metadata.AdditionalValues["Recursion"] = this.Recursion; metadata.AdditionalValues["Multiple"] = this.Multiple; metadata.AdditionalValues["DataTextField"] = this.DataTextField; metadata.AdditionalValues["DataValueField"] = this.DataValueField; metadata.DataTypeName = this.DataType; } private IDictionary<string, string> ParseEvents(string value) { try { if (string.IsNullOrWhiteSpace(value)) { value = "{}"; } return new Dictionary<string, string>(value.FromJson<IDictionary<string, string>>(), StringComparer.OrdinalIgnoreCase); } catch { return new Dictionary<string, string>(); } } public string AdditionalValues { get; set; } public string CascadeFrom { get; set; } public string Data { get; set; } public string DataTextField { get; set; } public string DataType { get; set; } public string DataValueField { get; set; } public string Events { get; set; } public System.Web.Mvc.HttpVerbs HttpVerbs { get; private set; } public bool Multiple { get; set; } public bool Recursion { get; set; } public string RemoteUrl { get; private set; } public bool ServerFiltering { get; set; } }
至于特性请参考以前的文章：基础拾遗------特性详解
