flex中的验证

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
			   xmlns:s="library://ns.adobe.com/flex/spark" 
			   xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600"
			   creationComplete="this.txt_uname.setFocus();"
			   defaultButton="{val_but}"
			   >
	<fx:Style>
		@namespace s "library://ns.adobe.com/flex/spark";
		@namespace mx "library://ns.adobe.com/flex/mx";
		.errorTip{
			font-size:14px;
			color: red;
		}
		mx|FormItem {
			font-size:14px;
		}
	</fx:Style>
	<s:layout>
		<s:BasicLayout/>
	</s:layout>
	<fx:Script>
		<![CDATA[
			import mx.controls.Alert;
			import mx.events.ValidationResultEvent;
			import mx.validators.Validator;
			protected function button1_clickHandler(event:MouseEvent):void
			{
				var d1:Number =  Date.parse(txt_df1.selectedDate);
				var d2:Number =  Date.parse(txt_df2.selectedDate);
				if(d1 >= d2) {
					Alert.show("结束日期必须大于开始日期");
				}
			}
			
			function doDcdate(date:Date):void{
				txt_uname.text = "当前时间： " + date.getFullYear() + "年" + (date.getMonth()+1) + "月" + date.getDate()+"日";
			}

			protected function v1_validHandler(event:ValidationResultEvent):void
			{
				//Alert.show("成功");
			}


			protected function v1_invalidHandler(event:ValidationResultEvent):void
			{
				//Alert.show("失败");
			}


			protected function val_but_clickHandler(event:MouseEvent):void
			{
				var errorArr:Array = Validator.validateAll([v1,v2]);
				if(errorArr.length > 0) {
					Alert.show("表单信息输入有误！");
				}
			}

		]]>
	</fx:Script>

	<fx:Declarations>
		<!-- 
			source: 对那个输入控件验证
			property="text": 对text属性内容验证
			trigger: 指定执行的触发控件（通常是按钮）
			triggerEvent: 接受触发类型（事件）
			required: 非空
			valid: 事件，在验证成功后自动触发
			inValid: 事件，在验证失败后自动触发
		-->
		<mx:StringValidator id="v1" source="{txt_uname}" property="text"
							trigger="{val_but}" triggerEvent="click"
							required="true" maxLength="6" requiredFieldError="用户名必须填写，嘿嘿！"
							valid="v1_validHandler(event)" invalid="v1_invalidHandler(event)"/>
		<mx:EmailValidator id="v2" source="{txt_uemail}" property="text"
						   trigger="{val_but}" triggerEvent="click" required="true" />
	</fx:Declarations>
	<mx:Form>
		<mx:FormItem label="用户名" required="true">
			<s:TextInput  id="txt_uname"/>
		</mx:FormItem> 
		<mx:FormItem label="密码">
			<s:TextInput  id="txt_upwd" displayAsPassword="true"/>
		</mx:FormItem>
		<mx:FormItem label="email">
			<s:TextInput  id="txt_uemail"/>
		</mx:FormItem>
		<mx:FormItem label="日历控件">
			<mx:DateField id="txt_df1" formatString="YYYY-MM-DD" width="200"/>
		</mx:FormItem>
		<mx:FormItem label="日历控件">
			<mx:DateField id="txt_df2" formatString="YYYY-MM-DD" width="200"/>
		</mx:FormItem>
		<mx:FormItem label="日历控件">
			<mx:DateChooser id="txt_dc" change="doDcdate(this.txt_dc.selectedDate)"/>
		</mx:FormItem>
		<s:Group>
			<s:layout>
				<s:HorizontalLayout/>
			</s:layout>
			<s:Button label="比较日期" click="button1_clickHandler(event)"/>
			<s:Button label="验证" id="val_but" click="val_but_clickHandler(event)"/>
		</s:Group>
	</mx:Form>
	
</s:Application>