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IfElseActivity

發(fā)布時間：2023/12/9 编程问答 54 豆豆

生活随笔收集整理的這篇文章主要介紹了 IfElseActivity 小編覺得挺不錯的,現(xiàn)在分享給大家,幫大家做個參考.

IfElseActivity

1.IfElseActivity有兩個IfElseBranch子控件，分別作為IfElse的兩個分支容器,系統(tǒng)自動添加，

2.其中左邊(為真件條)的IfElseBranch容器要設(shè)Condition

3.IfElse左邊(為真件條)的IfElseBranch容器的Condition有兩個條件模式:Code Condition,Declarative Rule Condition

Code Condition模式

Code Condition模式，由對e.Result賦不同值決定執(zhí)行不同的分支

要使用該模式，會在代碼中用到CodeCondition對象與CodeCondition對象的Condition事件

????'Code?Condition模式的判斷，由對e.Result賦不同值決定執(zhí)行不同的分支
?Private?Sub?ifElse_a_Condition()Sub?ifElse_a_Condition(ByVal?sender?As?System.Object,?ByVal?e?As?System.Workflow.Activities.ConditionalEventArgs)
????????'e.Result如果為真，就執(zhí)行左邊(為真件條)的IfElseBranch容器
????????'e.Result如果為假，就執(zhí)行右邊(為假件條)的IfElseBranch容器
????????If?temp?=?"456"?Then
????????????e.Result?=?True
????????Else
????????????e.Result?=?False
????????End?If
????End?Sub

雙擊無法進入代碼，可手寫該過程，

從下拉框綁定時如報錯，可在Workflow1.designer.vb中的手寫綁定代碼
'Workflow1.designer.vb中的綁定代碼
Dim?codecondition1?As?System.Workflow.Activities.CodeCondition?=?New?System.Workflow.Activities.CodeCondition
AddHandler?codecondition1.Condition,?AddressOf?Me.ifElse_a_Condition
Me.ifElseBranchActivity1.Condition?=?codecondition1

?

Declarative Rule Condition模式

Declarative Rule Condition模式：由指定的表達式的值是否符合條件定執(zhí)行不同的分支

代碼實現(xiàn)

Workflow1.rules

???? <RuleDefinitions.Conditions>

???????? <RuleExpressionCondition Name="Condition1">

????????????? <RuleExpressionCondition.Expression>

?????????????????? <ns0:CodeBinaryOperatorExpression Operator="ValueEquality" xmlns:ns0="clr-namespace:System.CodeDom;Assembly=System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">

?????????????????????? <ns0:CodeBinaryOperatorExpression.Left>

??????????????????????????? <ns0:CodeFieldReferenceExpression FieldName="temp">

???????????????????????????????? <ns0:CodeFieldReferenceExpression.TargetObject>

???????????????????????????????????? <ns0:CodeThisReferenceExpression />

???????????????????????????????? </ns0:CodeFieldReferenceExpression.TargetObject>

??????????????????????????? </ns0:CodeFieldReferenceExpression>

?????????????????????? </ns0:CodeBinaryOperatorExpression.Left>

?????????????????????? <ns0:CodeBinaryOperatorExpression.Right>

??????????????????????????? <ns0:CodePrimitiveExpression>

???????????????????????????????? <ns0:CodePrimitiveExpression.Value>

???????????????????????????????????? <ns1:String xmlns:ns1="clr-namespace:System;Assembly=mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">123</ns1:String>

???????????????????????????????? </ns0:CodePrimitiveExpression.Value>

??????????????????????????? </ns0:CodePrimitiveExpression>

?????????????????????? </ns0:CodeBinaryOperatorExpression.Right>

?????????????????? </ns0:CodeBinaryOperatorExpression>

????????????? </RuleExpressionCondition.Expression>

???????? </RuleExpressionCondition>

???? </RuleDefinitions.Conditions>

</RuleDefinitions>

?Dim ruleconditionreference1 As Workflow.Activities.Rules.RuleConditionReference = New .RuleConditionReference

?ruleconditionreference1.ConditionName = "Condition1"

?Me.ifElseBranchActivity3.Condition = ruleconditionreference1