概述

大家在做項(xiàng)目的時(shí)候，在實(shí)體類上添加一些特性,可以實(shí)現(xiàn)后端實(shí)體的數(shù)據(jù)校驗(yàn)。有時(shí)候，可能需要自定義驗(yàn)證屬性。實(shí)現(xiàn)原理：利用反射獲取實(shí)體的每一個(gè)屬性，并通過屬性獲取屬性上標(biāo)注的特性，調(diào)用特性的Validate方法（此方法自定義的）來驗(yàn)證屬性的值是否合法。

代碼實(shí)現(xiàn)

1、自定義CustomizedStringLength，繼承StringLengthAttribute

?public?class?CustomizedStringLength?:?StringLengthAttribute{private?Type?resourceType;private?string?resourceName;public?CustomizedStringLength(int?MaximumLength,?Type?ResourceType,?string?ResourceName)?:?base(MaximumLength){resourceType?=?ResourceType;resourceName?=?ResourceName;}public?CustomizedStringLength(int?MaximumLength)?:?base(MaximumLength){}public?override?string?FormatErrorMessage(string?name){string?fieldName?=?resourceType.GetProperty(resourceName).GetValue(resourceType).ToString();if?(MinimumLength?!=?0){this.ErrorMessage?=?string.Format(PageValidation.LimitLength,?fieldName,?MaximumLength,?MinimumLength);}else{this.ErrorMessage?=?string.Format(PageValidation.StringMaxLengthTemplate,?fieldName,?MaximumLength);}return?base.FormatErrorMessage(name);}} }

2、Application_Start全局注冊

??//在?Controller?之前對?Model?做處理(字串?Trim)ModelBinders.Binders.DefaultBinder?=?new?BQoolModelBinder();//註冊自訂的?Validation?(複寫預(yù)設(shè)的錯(cuò)誤訊息)CustomerValidation.RegisterCustomerValidation();DataAnnotationsModelValidatorProvider.RegisterAdapter(typeof(CustomizedRequired),?typeof(RequiredAttributeAdapter));DataAnnotationsModelValidatorProvider.RegisterAdapter(typeof(CustomizedStringLength),?typeof(StringLengthAttributeAdapter));

3、在字段調(diào)用CustomizedStringLength

????[CustomizedRequired(ResourceType:?typeof(AccountSettingsElement),?ResourceName:?"AccountEmail")][CustomizedStringLength(100,?ResourceType:?typeof(AccountSettingsElement),?ResourceName:?"AccountEmail")][CustomizedRegularExpression(@"^(([A-Za-z0-9]+_+)|([A-Za-z0-9]+\-+)|([A-Za-z0-9]+\.+)|([A-Za-z0-9]+\++))*[A-Za-z0-9]+@((\w+\-+)|(\w+\.))*\w{1,63}\.[a-zA-Z]{2,6}$",?ResourceType:?typeof(AccountSettingsElement),?ResourceName:?"AccountEmail")][Display(ResourceType?=?typeof(AccountSettingsElement),?Name?=?"AccountEmail")]public?string?AccountEmail?{?get;?set;?}

4、控制器上驗(yàn)證ModelState.IsValid

??if?(!ModelState.IsValid){Response.Redirect(Request.Url.AbsolutePath);Response.End();return;}

當(dāng)我們通過繼承ValidationAttribute創(chuàng)建我們自己的驗(yàn)證特性的時(shí)候，可以通過重寫公有方法IsValid或者受保護(hù)方法IsValid來實(shí)現(xiàn)我們自定義的驗(yàn)證邏輯。我們之所以能夠通過重寫任一個(gè)IsValid方法是我們自定義驗(yàn)證邏輯生效的原因在于這兩個(gè)方法在ValidationAttribute特殊的定義方法。

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