Validation數據驗證DataAnnotation機制和調試技巧 · Silverlight應用開發實例教程

![](https://box.kancloud.cn/2016-03-18_56eb67c868925.jpg) 在學習了[Silverlight Validation數據驗證基礎屬性和事件](http://www.cnblogs.com/jv9/archive/2010/09/09/1821891.html)后，大家對Silverlight數據驗證應該有了一個簡單明了的認識。今天，我將繼續介紹另外一種Silverlight的Validation驗證機制，DataAnnotation。在文章開始前，我想首先介紹一下Visual Studio中如何調試Silverlight的Validation代碼。 Visual Studio 2010調試Silverlight Validation設置技巧* 相信大家在運行上一篇的代碼時會發現，在異常出現時，Visual Studio會自動中斷和獲取當前異常錯誤信息，這為調試帶來了一些不便。 ![](https://box.kancloud.cn/2016-03-18_56eb67cc33865.jpg) 針對以上問題，我們可以在Visual Studio中進行簡單設置，暫時取消在Debug模式下對異常的捕獲，方法如下：首先到Debug菜單，選擇Exceptions菜單，也可以使用“Ctrl+Alt+E”，激活Exception窗口 ![](https://box.kancloud.cn/2016-03-18_56eb67cc42b33.jpg) ![](https://box.kancloud.cn/2016-03-18_56eb67cc56021.jpg) 點擊“Find”查找以下選項， System.Exception,將其后面的CheckBox取消選中， ![](https://box.kancloud.cn/2016-03-18_56eb67cc6e9e4.jpg) 這樣就實現了當數據驗證時，Visual Studio不再捕獲異常錯誤。對于本篇，我們將使用DataAnnotation驗證機制，該驗證機制與[上一篇](http://www.cnblogs.com/jv9/archive/2010/09/09/1821891.html)略有不同，所以，如果要實現Visual Studio忽略捕獲異常，要另外在Exception窗口搜索“System.ComponentModel.DataAnnotations.ValidationException"，同樣將其后面的CheckBox取消選中。 ![](https://box.kancloud.cn/2016-03-18_56eb67cc7e667.jpg) Visual Studio 2008和Silverlight 3開發環境中，默認情況下Exception沒有System.ComponentModel.DataAnnotations.ValidationException選項，開發人員可以自行添加一個新的異常即可，點擊“Add”按鈕， ![](https://box.kancloud.cn/2016-03-18_56eb67cc8e569.jpg) 在完成以上的操作后，再次執行Silverlight應用調試Validation時，Visual Studio不再出現異常捕獲，相對方便很多。 [Silverlight DataAnnotation](http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.aspx)驗證機制 **驗證Metadata屬性** Silverlight的DataAnnotation驗證機制是Silverlight 3發布WCF RIA Services測試版是推出的客戶端驗證機制，對于DataAnnotation的翻譯，可以理解為“數據元素注釋”驗證法。該驗證機制，使用了System.ComponentModel.DataAnnotations命名空間中的屬性類，通過對DataMember數據成員設置Metadata元數據屬性，對其驗證值進行判斷是否符合當前屬性條件，以達到Validation的效果。該驗證機制，多數運用于WCF RIA Services應用中. ~~~ ??????????private?string?_email; ??????????[Required(ErrorMessage?=?"必填選項")] ??????????public?string?email ??????????{ ??????????????get?{?return?_email;?} ??????????????set? ??????????????{ ??????????????????_email?=?value;? ??????????????} ?????????} ~~~ 從上面代碼可以看到屬性上面的注釋?[Required(ErrorMessage?=?"必填選項")]，該注釋就是DataAnnotations類中的固有屬性，其結果是判斷該控件內容是否為空，如果是，則彈出異常。目前常用的DataAnnotation屬性如下列表： <table class="MsoTableGrid" style="border-collapse: collapse; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-yfti-tbllook: 1184; mso-padding-alt: 0cm 5.4pt 0cm 5.4pt;" border="1" cellspacing="0" cellpadding="0"><tbody><tr style="height: 29.55pt; mso-yfti-irow: 0; mso-yfti-firstrow: yes;"><td style="padding-bottom: 0cm; background-color: transparent; padding-left: 5.4pt; width: 92.8pt; padding-right: 5.4pt; height: 29.55pt; padding-top: 0cm; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; border: black 1pt solid;" width="124"><span style="font-family: 宋體; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋體; mso-fareast-theme-font: minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;" lang="ZH-CN">屬性名稱</td><td style="border-bottom: black 1pt solid; border-left: #f0f0f0; padding-bottom: 0cm; background-color: transparent; padding-left: 5.4pt; width: 244.7pt; padding-right: 5.4pt; height: 29.55pt; border-top: black 1pt solid; border-right: black 1pt solid; padding-top: 0cm; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1;" width="326"><span style="font-family: 宋體; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋體; mso-fareast-theme-font: minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;" lang="ZH-CN">描述</td></tr><tr style="height: 29.55pt; mso-yfti-irow: 1;"><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; background-color: transparent; padding-left: 5.4pt; width: 92.8pt; padding-right: 5.4pt; height: 29.55pt; border-top: #f0f0f0; border-right: black 1pt solid; padding-top: 0cm; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1;" width="124">Required</td><td style="border-bottom: black 1pt solid; border-left: #f0f0f0; padding-bottom: 0cm; background-color: transparent; padding-left: 5.4pt; width: 244.7pt; padding-right: 5.4pt; height: 29.55pt; border-top: #f0f0f0; border-right: black 1pt solid; padding-top: 0cm; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; mso-border-bottom-themecolor: text1; mso-border-right-themecolor: text1;" width="326"><span style="font-family: 宋體; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋體; mso-fareast-theme-font: minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;" lang="ZH-CN">標識該屬性為必需參數，不能為空</td></tr><tr style="height: 29.55pt; mso-yfti-irow: 2;"><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; background-color: transparent; padding-left: 5.4pt; width: 92.8pt; padding-right: 5.4pt; height: 29.55pt; border-top: #f0f0f0; border-right: black 1pt solid; padding-top: 0cm; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1;" width="124">StringLength</td><td style="border-bottom: black 1pt solid; border-left: #f0f0f0; padding-bottom: 0cm; background-color: transparent; padding-left: 5.4pt; width: 244.7pt; padding-right: 5.4pt; height: 29.55pt; border-top: #f0f0f0; border-right: black 1pt solid; padding-top: 0cm; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; mso-border-bottom-themecolor: text1; mso-border-right-themecolor: text1;" width="326"><span style="font-family: 宋體; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋體; mso-fareast-theme-font: minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;" lang="ZH-CN">標識該字符串有長度限制，可以限制最小或最大長度</td></tr><tr style="height: 29.55pt; mso-yfti-irow: 3;"><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; background-color: transparent; padding-left: 5.4pt; width: 92.8pt; padding-right: 5.4pt; height: 29.55pt; border-top: #f0f0f0; border-right: black 1pt solid; padding-top: 0cm; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1;" width="124">Range</td><td style="border-bottom: black 1pt solid; border-left: #f0f0f0; padding-bottom: 0cm; background-color: transparent; padding-left: 5.4pt; width: 244.7pt; padding-right: 5.4pt; height: 29.55pt; border-top: #f0f0f0; border-right: black 1pt solid; padding-top: 0cm; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; mso-border-bottom-themecolor: text1; mso-border-right-themecolor: text1;" width="326"><span style="font-family: 宋體; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋體; mso-fareast-theme-font: minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;" lang="ZH-CN">標識該屬性值范圍，通常被用在數值型和日期型</td></tr><tr style="height: 29.55pt; mso-yfti-irow: 4;"><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; background-color: transparent; padding-left: 5.4pt; width: 92.8pt; padding-right: 5.4pt; height: 29.55pt; border-top: #f0f0f0; border-right: black 1pt solid; padding-top: 0cm; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1;" width="124">RegularExpression</td><td style="border-bottom: black 1pt solid; border-left: #f0f0f0; padding-bottom: 0cm; background-color: transparent; padding-left: 5.4pt; width: 244.7pt; padding-right: 5.4pt; height: 29.55pt; border-top: #f0f0f0; border-right: black 1pt solid; padding-top: 0cm; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; mso-border-bottom-themecolor: text1; mso-border-right-themecolor: text1;" width="326"><span style="font-family: 宋體; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋體; mso-fareast-theme-font: minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;" lang="ZH-CN">標識該屬性將根據提供的正則表達式進行對比驗證</td></tr><tr style="height: 29.55pt; mso-yfti-irow: 5; mso-yfti-lastrow: yes;"><td style="border-bottom: black 1pt solid; border-left: black 1pt solid; padding-bottom: 0cm; background-color: transparent; padding-left: 5.4pt; width: 92.8pt; padding-right: 5.4pt; height: 29.55pt; border-top: #f0f0f0; border-right: black 1pt solid; padding-top: 0cm; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1;" width="124">CustomValidation</td><td style="border-bottom: black 1pt solid; border-left: #f0f0f0; padding-bottom: 0cm; background-color: transparent; padding-left: 5.4pt; width: 244.7pt; padding-right: 5.4pt; height: 29.55pt; border-top: #f0f0f0; border-right: black 1pt solid; padding-top: 0cm; mso-border-alt: solid black .5pt; mso-border-themecolor: text1; mso-border-left-alt: solid black .5pt; mso-border-left-themecolor: text1; mso-border-top-alt: solid black .5pt; mso-border-top-themecolor: text1; mso-border-bottom-themecolor: text1; mso-border-right-themecolor: text1;" width="326"><span style="font-family: 宋體; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 宋體; mso-fareast-theme-font: minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;" lang="ZH-CN">標識該屬性將按照用戶提供的自定義驗證方法，進行數值驗證</td></tr></tbody></table> 在隨后的實例中，我們將一一演示這些屬性的使用方法。 **ValidationContext和Validator類** 閱讀過上一篇Silverlight Validation基礎的朋友應該知道，Silverlight的數據驗證，可以在數據成員的Setter中設置條件驗證，根據其驗證結果判斷是否符合驗證。例如： ~~~ ??????????private?int?_age; ??????????public?int?Age ??????????{ ??????????????get?{?return?_age;?} ??????????????set ??????????????{ ??????????????????if?(value?>?100?||?value?<?0) ??????????????????{ ??????????????????????throw?new?Exception("請輸入年齡值在0?-?100之間."); ?????????????????} ?????????????????_age?=?value; ?????????????} ?????????} ~~~ 在set中，判斷年齡值是否超過100歲或者低于0歲，如果不符合條件，則拋出異常，該異常將被Validation機制捕獲，并顯示到UI。而Silverlight的DataAnnotation機制，與上面驗證方法不同。Silverlight的DataAnnotation驗證機制，在添加驗證屬性后，不需要在Setter中進行驗證判斷，僅需要在Setter中激活該驗證屬性即可，而要實現激活驗證，則需要使用ValidationContext和Validator類。為了更好的理解Silverlight DataAnnotation驗證機制，我們來對這兩個類進行簡單的講解，首先說說[Validator類](http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.validator.aspx)，該類是一個靜態類，主要用來當數據成員被指定驗證元數據屬性時，驗證對象，屬性和方法。簡單的理解就是包含了各種具體驗證方法的類。例如上文代碼，我們使用了Require驗證屬性，Validator類將會根據該驗證屬性執行對應的驗證方法，對目標值進行判斷。在該類中，包含ValidateProperty方法和TryValidateProperty方法，可以分別對當前屬性進行驗證操作。而[ValiationContext類](http://msdn.microsoft.com/en-us/library/dd382177.aspx)，該類是對當前執行的數據驗證提供上下文描述的。簡單的理解，也就是為驗證提供數據傳輸，屬性標識等任務。我們對email屬性，進行簡單的修改，添加以上兩個類，讓該屬性Silverlight的DataAnnotation機制生效。 ~~~ ??????????private?string?_email; ??????????[Required(ErrorMessage?=?"必填選項")] ??????????public?string?email ??????????{ ??????????????get?{?return?_email;?} ??????????????set? ??????????????{ ??????????????????var?tmpValidator?=?new?ValidationContext(this,?null,?null); ??????????????????tmpValidator.MemberName?=?"email"; ?????????????????Validator.ValidateProperty(value,?tmpValidator); ?????????????????_email?=?value;? ?????????????} ?????????} ~~~ 在上文代碼中，我們定義一個ValidationContext實例，該實例中包含了需要驗證對象的引用，并且，我們定義了驗證對象的MemberName，通過調用Validator.ValidateProperty靜態方法，檢查目標數據是否符合當前驗證屬性，如果返回False，則拋出一個ValidationException。上面代碼也可簡寫為： ~~~ Validator.ValidateProperty(value,?new?ValidationContext(this,?null,?null)?{?MemberName?=?"email"?}); ~~~ 當運行實例后，輸入空格在郵件文本框中，Silverlight的DataAnnotation驗證機制將被激活，生成如下效果： ![](https://box.kancloud.cn/2016-03-18_56eb67cc9dd9d.jpg) 在理解了上面的Silverlight的DataAnnotation驗證機制的基本類和屬性后，我們可以做幾個簡單的實例，來加深理解。 1. StringLength，定義Password密碼框最大可輸入6個字符， ~~~ ?????????????<StackPanel?Orientation="Horizontal"?Margin="5"> ?????????????????<TextBlock?Text="密???碼:?"?VerticalAlignment="Center"/> ?????????????????<TextBox?x:Name="txtPassword"?Width="200"?DataContext="{Binding?Source={StaticResource?UserDataContext}}"?Text="{Binding?Path=password,?Mode=TwoWay,ValidatesOnExceptions=True,?NotifyOnValidationError=True}"?/> ?????????????</StackPanel> ~~~ ~~~ ??????????private?string?_password; ??????????[StringLength(6,?ErrorMessage="密碼不能超過6個字符")] ??????????public?string?password ??????????{ ??????????????get?{?return?_password;?} ??????????????set? ??????????????{ ??????????????????Validator.ValidateProperty(value,?new?ValidationContext(this,?null,?null)?{?MemberName?=?"password"?}); ??????????????????_password?=?value;? ?????????????} ?????????} ~~~ ![](https://box.kancloud.cn/2016-03-18_56eb67ccaef0b.jpg) 2. Range，我們使用Range屬性設置Age年齡的有效范圍， ~~~ ?<StackPanel?Orientation="Horizontal"?Margin="5"> ?????????????????<TextBlock?Text="年???齡:?"?VerticalAlignment="Center"/> ?????????????????<TextBox?x:Name="txtAge"?Width="200"?DataContext="{Binding?Source={StaticResource?UserDataContext}}"?Text="{Binding?Path=Age,?Mode=TwoWay,?NotifyOnValidationError=True,?ValidatesOnExceptions=True}"?/> ?????????????</StackPanel> ~~~ ~~~ ??????????private?int?_age; ??????????[Range(0,?100,?ErrorMessage?=?"請輸入年齡值在0?-?100之間")] ??????????public?int?Age ??????????{ ??????????????get?{?return?_age;?} ??????????????set ??????????????{ ??????????????????Validator.ValidateProperty(value,?new?ValidationContext(this,?null,?null)?{?MemberName?=?"Age"?}); ?????????????????_age?=?value; ?????????????} ?????????} ~~~ ![](https://box.kancloud.cn/2016-03-18_56eb67ccc484a.jpg) 3. RegularExpression，我們使用正則表達式屬性，驗證郵件輸入框。 ~~~ ?<StackPanel?Orientation="Horizontal"?Margin="5"> ?????????????????<TextBlock?Text="郵???件:?"?VerticalAlignment="Center"/> ?????????????????<TextBox?x:Name="txtEmail"?Width="200"?DataContext="{Binding?Source={StaticResource?UserDataContext}}"?Text="{Binding?Path=email,?Mode=TwoWay,?ValidatesOnNotifyDataErrors=False,?NotifyOnValidationError=True,?ValidatesOnExceptions=True}"?/> ?????????????</StackPanel> ~~~ ~~~ ??????????private?string?_email; ??????????[Required(ErrorMessage?=?"必填選項")] ??????????[RegularExpression(@"^([0-9a-zA-Z]([-./w]*[0-9a-zA-Z])*@([0-9a-zA-Z][-/w]*[0-9a-zA-Z]/.)+[a-zA-Z]{2,9})$",ErrorMessage="請輸入正確的Email格式")] ??????????public?string?email ??????????{ ??????????????get?{?return?_email;?} ??????????????set? ??????????????{ ??????????????????var?tmpValidator?=?new?ValidationContext(this,?null,?null); ?????????????????tmpValidator.MemberName?=?"email"; ?????????????????Validator.ValidateProperty(value,?tmpValidator); ?????????????????_email?=?value;? ?????????????} ?????????} ~~~ ![](https://box.kancloud.cn/2016-03-18_56eb67ccd38a6.jpg) 4. 自定義驗證方法的應用我們創建一個簡單的自定義驗證方法，驗證用戶名是否為jv9. 首先創建自定義驗證類，CustomizeValidation，在類中添加引用，using System.ComponentModel.DataAnnotations; 然后繼承ValidationAttribute類，使其預定義該類為自定義驗證屬性，完成上面的設置后，即可創建自定義驗證方法。 ~~~ ?????public?class?CustomizeValidation?:?ValidationAttribute ?????{ ?????????protected?override?ValidationResult?IsValid(object?value,?ValidationContext?validationContext) ?????????{ ?????????????String?checkName?=?value.ToString(); ? ?????????????return?checkName?==?"jv9"???ValidationResult.Success?:?new?ValidationResult("請使用指定用戶名"); ?????????} ?????} ~~~ 在Name屬性中，進行調用， ~~~ ??????????private?string?_name; ??????????[CustomizeValidation] ??????????public?string?Name ??????????{ ??????????????get?{?return?_name;?} ??????????????set? ??????????????{ ??????????????????Validator.ValidateProperty(value,?new?ValidationContext(this,?null,?null)?{?MemberName?=?"Name"?}); ??????????????????if?(string.IsNullOrEmpty(value)) ?????????????????{ ?????????????????????throw?new?Exception("用戶名不能為空."); ?????????????????} ?????????????????_name?=?value;? ?????????????} ?????????} ~~~ ![](https://box.kancloud.cn/2016-03-18_56eb67cce6577.jpg) 對于Silverlight的DataAnnotation驗證機制，相比其他驗證機制使用起來較為簡單，但是其本身具有一定局限性。特別是當數據成員來自服務器端，會因為類庫無法共享使用造成無法正常驗證。前文曾提及，該驗證機制多數用在WCF RIA Services，因為WCF RIA應用提供的數據層，可生成對應客戶端代碼，即可實現在客戶端的DataAnnotation驗證。在隨后的實例中，我將演示一套WCF RIA服務下的驗證實例。今天講到這里，希望大家能夠有所收獲。 [源代碼下載](http://files.cnblogs.com/jv9/SilverlightValidationDemo.rar) 歡迎大家加入"專注Silverlight" 技術討論群： 32679955(六群) 23413513(五群) 32679922(四群) 100844510(三群) 37891947(二群) 22308706(一群)