Atividades de Recolha em WF

Artigo
03/12/2024

As atividades de coleção são usadas para trabalhar com objetos de coleção em um fluxo de trabalho. O .NET Framework 4.6.1 tem atividades fornecidas pelo sistema para adicionar e remover itens de uma coleção, testar a existência de um item em uma coleção e limpar uma coleção. ExistsInCollection e RemoveFromCollection ter um OutArgument<T> do tipo Boolean, que indica o resultado.

Importante

Se uma atividade de coleta for executada antes de definir o objeto de coleção subjacente, um InvalidOperationException será lançado e a atividade falhará.

Atividades de recolha

Tipo de atividade	Description
AddToCollection<T>	Adiciona um item a uma coleção especificada.
ClearCollection<T>	Limpa todos os itens de uma coleção especificada.
ExistsInCollection<T>	Retorna `true` se um item existir em uma coleção.
RemoveFromCollection<T>	Remove um item de uma coleção especificada e retorna `true` se o item foi removido com êxito.

Usando atividades de coleta

O exemplo de código a seguir demonstra como interagir com uma coleção declarada como uma variável de fluxo de trabalho. A coleção usada é um List<T> dos String objetos chamados fruitList.

Variable<ICollection<string>> fruitList = new Variable<ICollection<string>>  
{  
    Default = new VisualBasicValue<ICollection<string>>("New List(Of String) From {\"Apple\", \"Orange\"}"),  
    Name = "FruitList"  
};  
  
Variable<bool> result = new Variable<bool>  
{  
    Name = "Result"  
};  
  
Activity wf = new Sequence  
{  
    Variables = { fruitList, result },  
  
    Activities =
    {  
        new If  
        {  
            Condition = new ExistsInCollection<string>  
            {  
                Collection = fruitList,  
                Item = "Pear"  
            },  
            Then = new AddToCollection<string>  
            {  
                Collection = fruitList,  
                Item = "Pear"  
            },  
            Else = new RemoveFromCollection<string>  
            {  
                Collection = fruitList,  
                Item = "Apple"  
            }  
        },  
  
        new RemoveFromCollection<string>  
        {  
            Collection = fruitList,  
            Item = "Apple",  
            Result = result  
        },  
        new If  
        {  
            Condition = result,  
            Then = new ClearCollection<string>  
            {  
                Collection = fruitList,  
            }  
        }  
    }  
};

<Sequence  
   xmlns="http://schemas.microsoft.com/netfx/2009/xaml/activities"  
   xmlns:scg="clr-namespace:System.Collections.Generic;assembly=mscorlib"  
   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">  
  <Sequence.Variables>  
    <x:Reference>__ReferenceID0</x:Reference>  
    <x:Reference>__ReferenceID1</x:Reference>  
  </Sequence.Variables>  
  <If>  
    <If.Condition>  
      <InArgument  
         x:TypeArguments="x:Boolean">  
        <ExistsInCollection  
           x:TypeArguments="x:String"  
           Item="Pear">  
          <ExistsInCollection.Result>  
            <OutArgument  
               x:TypeArguments="x:Boolean" />  
          </ExistsInCollection.Result>  
          <InArgument  
             x:TypeArguments="scg:ICollection(x:String)">  
            <VariableValue  
               x:TypeArguments="scg:ICollection(x:String)">  
              <VariableValue.Result>  
                <OutArgument  
                   x:TypeArguments="scg:ICollection(x:String)" />  
              </VariableValue.Result>  
              <VariableValue.Variable>  
                <Variable  
                   x:TypeArguments="scg:ICollection(x:String)"  
                   x:Name="__ReferenceID0"  
                   Default="[New List(Of String) From {"Apple", "Orange"}]"  
                   Name="FruitList" />  
              </VariableValue.Variable>  
            </VariableValue>  
          </InArgument>  
        </ExistsInCollection>  
      </InArgument>  
    </If.Condition>  
    <If.Then>  
      <AddToCollection  
         x:TypeArguments="x:String"  
         Item="Pear">  
        <InArgument  
           x:TypeArguments="scg:ICollection(x:String)">  
          <VariableValue  
             x:TypeArguments="scg:ICollection(x:String)"  
             Variable="{x:Reference __ReferenceID0}">  
            <VariableValue.Result>  
              <OutArgument  
                 x:TypeArguments="scg:ICollection(x:String)" />  
            </VariableValue.Result>  
          </VariableValue>  
        </InArgument>  
      </AddToCollection>  
    </If.Then>  
    <If.Else>  
      <RemoveFromCollection  
         x:TypeArguments="x:String"  
         Item="Apple"  
         Result="{x:Null}">  
        <InArgument  
           x:TypeArguments="scg:ICollection(x:String)">  
          <VariableValue  
             x:TypeArguments="scg:ICollection(x:String)"  
             Variable="{x:Reference __ReferenceID0}">  
            <VariableValue.Result>  
              <OutArgument  
                 x:TypeArguments="scg:ICollection(x:String)" />  
            </VariableValue.Result>  
          </VariableValue>  
        </InArgument>  
      </RemoveFromCollection>  
    </If.Else>  
  </If>  
  <RemoveFromCollection  
     x:TypeArguments="x:String"  
     Item="Apple">  
    <RemoveFromCollection.Result>  
      <OutArgument  
         x:TypeArguments="x:Boolean">  
        <VariableReference  
           x:TypeArguments="x:Boolean">  
          <VariableReference.Result>  
            <OutArgument  
               x:TypeArguments="Location(x:Boolean)" />  
          </VariableReference.Result>  
          <VariableReference.Variable>  
            <Variable  
               x:TypeArguments="x:Boolean"  
               x:Name="__ReferenceID1"  
               Name="Result" />  
          </VariableReference.Variable>  
        </VariableReference>  
      </OutArgument>  
    </RemoveFromCollection.Result>  
    <InArgument  
       x:TypeArguments="scg:ICollection(x:String)">  
      <VariableValue  
         x:TypeArguments="scg:ICollection(x:String)"  
         Variable="{x:Reference __ReferenceID0}">  
        <VariableValue.Result>  
          <OutArgument  
             x:TypeArguments="scg:ICollection(x:String)" />  
        </VariableValue.Result>  
      </VariableValue>  
    </InArgument>  
  </RemoveFromCollection>  
  <If>  
    <If.Condition>  
      <InArgument  
         x:TypeArguments="x:Boolean">  
        <VariableValue  
           x:TypeArguments="x:Boolean"  
           Variable="{x:Reference __ReferenceID1}">  
          <VariableValue.Result>  
            <OutArgument  
               x:TypeArguments="x:Boolean" />  
          </VariableValue.Result>  
        </VariableValue>  
      </InArgument>  
    </If.Condition>  
    <If.Then>  
      <ClearCollection  
         x:TypeArguments="x:String">  
        <InArgument  
           x:TypeArguments="scg:ICollection(x:String)">  
          <VariableValue  
             x:TypeArguments="scg:ICollection(x:String)"  
             Variable="{x:Reference __ReferenceID0}">  
            <VariableValue.Result>  
              <OutArgument  
                 x:TypeArguments="scg:ICollection(x:String)" />  
            </VariableValue.Result>  
          </VariableValue>  
        </InArgument>  
      </ClearCollection>  
    </If.Then>  
  </If>  
</Sequence>

Os exemplos de código acima também podem ser criados usando CSharpValue<TResult> em vez de VisualBasicValue<TResult>

Variable<ICollection<string>> fruitList = new Variable<ICollection<string>>  
{  
    Default = new CSharpValue<ICollection<string>>("new List<String> From {\"Apple\", \"Orange\"};"),  
    Name = "FruitList"  
};  
  
Variable<bool> result = new Variable<bool>  
{  
    Name = "Result"  
};  
  
Activity wf = new Sequence  
{  
    Variables = { fruitList, result },  
  
    Activities =
    {  
        new If  
        {  
            Condition = new ExistsInCollection<string>  
            {  
                Collection = fruitList,  
                Item = "Pear"  
            },  
            Then = new AddToCollection<string>  
            {  
                Collection = fruitList,  
                Item = "Pear"  
            },  
            Else = new RemoveFromCollection<string>  
            {  
                Collection = fruitList,  
                Item = "Apple"  
            }  
        },  
  
        new RemoveFromCollection<string>  
        {  
            Collection = fruitList,  
            Item = "Apple",  
            Result = result  
        },  
        new If  
        {  
            Condition = result,  
            Then = new ClearCollection<string>  
            {  
                Collection = fruitList,  
            }  
        }  
    }  
};

<Sequence  
   xmlns="http://schemas.microsoft.com/netfx/2009/xaml/activities"  
   xmlns:scg="clr-namespace:System.Collections.Generic;assembly=mscorlib"  
   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">  
  <Sequence.Variables>  
    <x:Reference>__ReferenceID0</x:Reference>  
    <x:Reference>__ReferenceID1</x:Reference>  
  </Sequence.Variables>  
  <If>  
    <If.Condition>  
      <InArgument  
         x:TypeArguments="x:Boolean">  
        <ExistsInCollection  
           x:TypeArguments="x:String"  
           Item="Pear">  
          <ExistsInCollection.Result>  
            <OutArgument  
               x:TypeArguments="x:Boolean" />  
          </ExistsInCollection.Result>  
          <InArgument  
             x:TypeArguments="scg:ICollection(x:String)">  
            <VariableValue  
               x:TypeArguments="scg:ICollection(x:String)">  
              <VariableValue.Result>  
                <OutArgument  
                   x:TypeArguments="scg:ICollection(x:String)" />  
              </VariableValue.Result>  
              <VariableValue.Variable>  
                <Variable  
                   x:TypeArguments="scg:ICollection(x:String)"  
                   x:Name="__ReferenceID0"  
                   Default="[new List<String> From {"Apple", "Orange"};]"  
                   Name="FruitList" />  
              </VariableValue.Variable>  
            </VariableValue>  
          </InArgument>  
        </ExistsInCollection>  
      </InArgument>  
    </If.Condition>  
    <If.Then>  
      <AddToCollection  
         x:TypeArguments="x:String"  
         Item="Pear">  
        <InArgument  
           x:TypeArguments="scg:ICollection(x:String)">  
          <VariableValue  
             x:TypeArguments="scg:ICollection(x:String)"  
             Variable="{x:Reference __ReferenceID0}">  
            <VariableValue.Result>  
              <OutArgument  
                 x:TypeArguments="scg:ICollection(x:String)" />  
            </VariableValue.Result>  
          </VariableValue>  
        </InArgument>  
      </AddToCollection>  
    </If.Then>  
    <If.Else>  
      <RemoveFromCollection  
         x:TypeArguments="x:String"  
         Item="Apple"  
         Result="{x:Null}">  
        <InArgument  
           x:TypeArguments="scg:ICollection(x:String)">  
          <VariableValue  
             x:TypeArguments="scg:ICollection(x:String)"  
             Variable="{x:Reference __ReferenceID0}">  
            <VariableValue.Result>  
              <OutArgument  
                 x:TypeArguments="scg:ICollection(x:String)" />  
            </VariableValue.Result>  
          </VariableValue>  
        </InArgument>  
      </RemoveFromCollection>  
    </If.Else>  
  </If>  
  <RemoveFromCollection  
     x:TypeArguments="x:String"  
     Item="Apple">  
    <RemoveFromCollection.Result>  
      <OutArgument  
         x:TypeArguments="x:Boolean">  
        <VariableReference  
           x:TypeArguments="x:Boolean">  
          <VariableReference.Result>  
            <OutArgument  
               x:TypeArguments="Location(x:Boolean)" />  
          </VariableReference.Result>  
          <VariableReference.Variable>  
            <Variable  
               x:TypeArguments="x:Boolean"  
               x:Name="__ReferenceID1"  
               Name="Result" />  
          </VariableReference.Variable>  
        </VariableReference>  
      </OutArgument>  
    </RemoveFromCollection.Result>  
    <InArgument  
       x:TypeArguments="scg:ICollection(x:String)">  
      <VariableValue  
         x:TypeArguments="scg:ICollection(x:String)"  
         Variable="{x:Reference __ReferenceID0}">  
        <VariableValue.Result>  
          <OutArgument  
             x:TypeArguments="scg:ICollection(x:String)" />  
        </VariableValue.Result>  
      </VariableValue>  
    </InArgument>  
  </RemoveFromCollection>  
  <If>  
    <If.Condition>  
      <InArgument  
         x:TypeArguments="x:Boolean">  
        <VariableValue  
           x:TypeArguments="x:Boolean"  
           Variable="{x:Reference __ReferenceID1}">  
          <VariableValue.Result>  
            <OutArgument  
               x:TypeArguments="x:Boolean" />  
          </VariableValue.Result>  
        </VariableValue>  
      </InArgument>  
    </If.Condition>  
    <If.Then>  
      <ClearCollection  
         x:TypeArguments="x:String">  
        <InArgument  
           x:TypeArguments="scg:ICollection(x:String)">  
          <VariableValue  
             x:TypeArguments="scg:ICollection(x:String)"  
             Variable="{x:Reference __ReferenceID0}">  
            <VariableValue.Result>  
              <OutArgument  
                 x:TypeArguments="scg:ICollection(x:String)" />  
            </VariableValue.Result>  
          </VariableValue>  
        </InArgument>  
      </ClearCollection>  
    </If.Then>  
  </If>  
</Sequence>

Consulte também

Criação de fluxos de trabalho, atividades e expressões usando código imperativo

Partilhar via

Atividades de Recolha em WF

Atividades de recolha

Usando atividades de coleta

Consulte também

Recursos adicionais