If 建構函式

定義

命名空間:

System.Activities.Statements

組件:

System.Activities.dll

建立 If 類別的新執行個體。

多載

If()	建立 If 類別的新執行個體。
If(Activity<Boolean>)	使用指定的條件建立 If 類別的新執行個體。
If(InArgument<Boolean>)	使用指定的條件建立 If 類別的新執行個體。
If(Expression<Func<ActivityContext,Boolean>>)	使用指定的條件建立 If 類別的新執行個體。

If()

建立 If 類別的新執行個體。

public:
 If();

public If ();

Public Sub New ()

範例

下列程式碼範例將示範如何建立 If 活動。

new If
{
    // check if the order is asking for Widgets
    Condition = new InArgument<bool>( (e) => po.Get(e).PartName.Equals("Widget") ),
    Then = new If
    {
        // check if we have enough widgets in stock
        Condition = new InArgument<bool>( (e) => po.Get(e).Quantity < 100 ),
        Then = new SendReply
        {
            DisplayName = "Successful response",
            Request = submitPO,
            Content = SendContent.Create(new InArgument<string>( (e) => string.Format("Success: {0} Widgets have been ordered!", po.Get(e).Quantity)) )
        },
        // if we don't have enough widgets, throw an unhandled exception from this operation's body
        Else = new Throw
        {
            Exception = new InArgument<Exception>((e) => new Exception("We don't have that many Widgets."))
        }
    },
    // if its not for widgets, reply to the client that we don't carry that part by sending back an expected fault type (POFault)
    Else = new SendReply
    {
        DisplayName = "Expected fault",
        Request = submitPO,
        Content = SendContent.Create(new InArgument<FaultException<POFault>>( (e) => new FaultException<POFault>(
            new POFault
            {
                Problem = string.Format("This company does not carry {0}s, but we do carry Widgets.", po.Get(e).PartName),
                Solution = "Try your local hardware store."
            },
            new FaultReason("This is an expected fault.")
            )))
    }
}

If(Activity<Boolean>)

使用指定的條件建立 If 類別的新執行個體。

public:
 If(System::Activities::Activity<bool> ^ condition);

public If (System.Activities.Activity<bool> condition);

new System.Activities.Statements.If : System.Activities.Activity<bool> -> System.Activities.Statements.If

Public Sub New (condition As Activity(Of Boolean))

參數

condition

Activity<Boolean>

執行條件。

範例

下列程式碼範例將示範如何建立 If 活動。

new If
{
    // check if the order is asking for Widgets
    Condition = new InArgument<bool>( (e) => po.Get(e).PartName.Equals("Widget") ),
    Then = new If
    {
        // check if we have enough widgets in stock
        Condition = new InArgument<bool>( (e) => po.Get(e).Quantity < 100 ),
        Then = new SendReply
        {
            DisplayName = "Successful response",
            Request = submitPO,
            Content = SendContent.Create(new InArgument<string>( (e) => string.Format("Success: {0} Widgets have been ordered!", po.Get(e).Quantity)) )
        },
        // if we don't have enough widgets, throw an unhandled exception from this operation's body
        Else = new Throw
        {
            Exception = new InArgument<Exception>((e) => new Exception("We don't have that many Widgets."))
        }
    },
    // if its not for widgets, reply to the client that we don't carry that part by sending back an expected fault type (POFault)
    Else = new SendReply
    {
        DisplayName = "Expected fault",
        Request = submitPO,
        Content = SendContent.Create(new InArgument<FaultException<POFault>>( (e) => new FaultException<POFault>(
            new POFault
            {
                Problem = string.Format("This company does not carry {0}s, but we do carry Widgets.", po.Get(e).PartName),
                Solution = "Try your local hardware store."
            },
            new FaultReason("This is an expected fault.")
            )))
    }
}

If(InArgument<Boolean>)

使用指定的條件建立 If 類別的新執行個體。

public:
 If(System::Activities::InArgument<bool> ^ condition);

public If (System.Activities.InArgument<bool> condition);

new System.Activities.Statements.If : System.Activities.InArgument<bool> -> System.Activities.Statements.If

Public Sub New (condition As InArgument(Of Boolean))

參數

condition

InArgument<Boolean>

執行條件。

範例

下列程式碼範例將示範如何建立 If 活動。

new If
{
    // check if the order is asking for Widgets
    Condition = new InArgument<bool>( (e) => po.Get(e).PartName.Equals("Widget") ),
    Then = new If
    {
        // check if we have enough widgets in stock
        Condition = new InArgument<bool>( (e) => po.Get(e).Quantity < 100 ),
        Then = new SendReply
        {
            DisplayName = "Successful response",
            Request = submitPO,
            Content = SendContent.Create(new InArgument<string>( (e) => string.Format("Success: {0} Widgets have been ordered!", po.Get(e).Quantity)) )
        },
        // if we don't have enough widgets, throw an unhandled exception from this operation's body
        Else = new Throw
        {
            Exception = new InArgument<Exception>((e) => new Exception("We don't have that many Widgets."))
        }
    },
    // if its not for widgets, reply to the client that we don't carry that part by sending back an expected fault type (POFault)
    Else = new SendReply
    {
        DisplayName = "Expected fault",
        Request = submitPO,
        Content = SendContent.Create(new InArgument<FaultException<POFault>>( (e) => new FaultException<POFault>(
            new POFault
            {
                Problem = string.Format("This company does not carry {0}s, but we do carry Widgets.", po.Get(e).PartName),
                Solution = "Try your local hardware store."
            },
            new FaultReason("This is an expected fault.")
            )))
    }
}

If(Expression<Func<ActivityContext,Boolean>>)

使用指定的條件建立 If 類別的新執行個體。

public:
 If(System::Linq::Expressions::Expression<Func<System::Activities::ActivityContext ^, bool> ^> ^ condition);

public If (System.Linq.Expressions.Expression<Func<System.Activities.ActivityContext,bool>> condition);

new System.Activities.Statements.If : System.Linq.Expressions.Expression<Func<System.Activities.ActivityContext, bool>> -> System.Activities.Statements.If

Public Sub New (condition As Expression(Of Func(Of ActivityContext, Boolean)))

參數

condition

Expression<Func<ActivityContext,Boolean>>

執行條件。

範例

下列程式碼範例將示範如何建立 If 活動。

new If
{
    // check if the order is asking for Widgets
    Condition = new InArgument<bool>( (e) => po.Get(e).PartName.Equals("Widget") ),
    Then = new If
    {
        // check if we have enough widgets in stock
        Condition = new InArgument<bool>( (e) => po.Get(e).Quantity < 100 ),
        Then = new SendReply
        {
            DisplayName = "Successful response",
            Request = submitPO,
            Content = SendContent.Create(new InArgument<string>( (e) => string.Format("Success: {0} Widgets have been ordered!", po.Get(e).Quantity)) )
        },
        // if we don't have enough widgets, throw an unhandled exception from this operation's body
        Else = new Throw
        {
            Exception = new InArgument<Exception>((e) => new Exception("We don't have that many Widgets."))
        }
    },
    // if its not for widgets, reply to the client that we don't carry that part by sending back an expected fault type (POFault)
    Else = new SendReply
    {
        DisplayName = "Expected fault",
        Request = submitPO,
        Content = SendContent.Create(new InArgument<FaultException<POFault>>( (e) => new FaultException<POFault>(
            new POFault
            {
                Problem = string.Format("This company does not carry {0}s, but we do carry Widgets.", po.Get(e).PartName),
                Solution = "Try your local hardware store."
            },
            new FaultReason("This is an expected fault.")
            )))
    }
}