Expression.Switch Method

Reference

Definition

Namespace:: System.Linq.Expressions

Assembly:: System.Linq.Expressions.dll

Assembly:: System.Core.dll

Assembly:: netstandard.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Creates a SwitchExpression that represents a switch statement.

Overloads

Switch(Type, Expression, Expression, MethodInfo, SwitchCase[])	Creates a SwitchExpression that represents a `switch` statement that has a default case.
Switch(Expression, SwitchCase[])	Creates a SwitchExpression that represents a `switch` statement without a default case.
Switch(Expression, Expression, SwitchCase[])	Creates a SwitchExpression that represents a `switch` statement that has a default case.
Switch(Expression, Expression, MethodInfo, IEnumerable<SwitchCase>)	Creates a SwitchExpression that represents a `switch` statement that has a default case.
Switch(Expression, Expression, MethodInfo, SwitchCase[])	Creates a SwitchExpression that represents a `switch` statement that has a default case.
Switch(Type, Expression, Expression, MethodInfo, IEnumerable<SwitchCase>)	Creates a SwitchExpression that represents a `switch` statement that has a default case.

Switch(Type, Expression, Expression, MethodInfo, SwitchCase[])

Source:: SwitchExpression.cs

Source:: SwitchExpression.cs

Source:: SwitchExpression.cs

Creates a SwitchExpression that represents a switch statement that has a default case.

public:
 static System::Linq::Expressions::SwitchExpression ^ Switch(Type ^ type, System::Linq::Expressions::Expression ^ switchValue, System::Linq::Expressions::Expression ^ defaultBody, System::Reflection::MethodInfo ^ comparison, ... cli::array <System::Linq::Expressions::SwitchCase ^> ^ cases);

public static System.Linq.Expressions.SwitchExpression Switch (Type type, System.Linq.Expressions.Expression switchValue, System.Linq.Expressions.Expression defaultBody, System.Reflection.MethodInfo comparison, params System.Linq.Expressions.SwitchCase[] cases);

public static System.Linq.Expressions.SwitchExpression Switch (Type? type, System.Linq.Expressions.Expression switchValue, System.Linq.Expressions.Expression? defaultBody, System.Reflection.MethodInfo? comparison, params System.Linq.Expressions.SwitchCase[]? cases);

static member Switch : Type * System.Linq.Expressions.Expression * System.Linq.Expressions.Expression * System.Reflection.MethodInfo * System.Linq.Expressions.SwitchCase[] -> System.Linq.Expressions.SwitchExpression

Public Shared Function Switch (type As Type, switchValue As Expression, defaultBody As Expression, comparison As MethodInfo, ParamArray cases As SwitchCase()) As SwitchExpression

Parameters

type: Type

The result type of the switch.

switchValue: Expression

The value to be tested against each case.

defaultBody: Expression

The result of the switch if switchValue does not match any of the cases.

comparison: MethodInfo

The equality comparison method to use.

cases: SwitchCase[]

The set of cases for this switch expression.

Returns

SwitchExpression

The created SwitchExpression.

Applies to

Switch(Expression, SwitchCase[])

Source:: SwitchExpression.cs

Source:: SwitchExpression.cs

Source:: SwitchExpression.cs

Creates a SwitchExpression that represents a switch statement without a default case.

public:
 static System::Linq::Expressions::SwitchExpression ^ Switch(System::Linq::Expressions::Expression ^ switchValue, ... cli::array <System::Linq::Expressions::SwitchCase ^> ^ cases);

public static System.Linq.Expressions.SwitchExpression Switch (System.Linq.Expressions.Expression switchValue, params System.Linq.Expressions.SwitchCase[] cases);

public static System.Linq.Expressions.SwitchExpression Switch (System.Linq.Expressions.Expression switchValue, params System.Linq.Expressions.SwitchCase[]? cases);

static member Switch : System.Linq.Expressions.Expression * System.Linq.Expressions.SwitchCase[] -> System.Linq.Expressions.SwitchExpression

Public Shared Function Switch (switchValue As Expression, ParamArray cases As SwitchCase()) As SwitchExpression

Parameters

switchValue: Expression

The value to be tested against each case.

cases: SwitchCase[]

The set of cases for this switch expression.

Returns

SwitchExpression

The created SwitchExpression.

Examples

The following example demonstrates how to create an expression that represents a switch statement without a default case.

// Add the following directive to the file:
// using System.Linq.Expressions;

// An expression that represents the switch value.
ConstantExpression switchValue = Expression.Constant(2);

// This expression represents a switch statement
// without a default case.
SwitchExpression switchExpr =
    Expression.Switch(
        switchValue,
        new SwitchCase[] {
            Expression.SwitchCase(
                Expression.Call(
                    null,
                    typeof(Console).GetMethod("WriteLine", new Type[] { typeof(String) }),
                    Expression.Constant("First")
                ),
                Expression.Constant(1)
            ),
            Expression.SwitchCase(
                Expression.Call(
                    null,
                    typeof(Console).GetMethod("WriteLine", new Type[] { typeof(String) }),
                    Expression.Constant("Second")
                ),
                Expression.Constant(2)
            )
        }
    );

// The following statement first creates an expression tree,
// then compiles it, and then runs it.
Expression.Lambda<Action>(switchExpr).Compile()();

// This code example produces the following output:
//
// Second

' Add the following directive to the file:
' Imports System.Linq.Expressions

' An expression that represents the switch value.
Dim switchValue As ConstantExpression = Expression.Constant(2)

' This expression represents a switch statement 
' without a default case.
Dim switchExpr As SwitchExpression =
Expression.Switch(
    switchValue,
    New SwitchCase() {
        Expression.SwitchCase(
            Expression.Call(
                Nothing,
                GetType(Console).GetMethod("WriteLine", New Type() {GetType(String)}),
                Expression.Constant("First")
            ),
            Expression.Constant(1)
        ),
        Expression.SwitchCase(
            Expression.Call(
                Nothing,
                GetType(Console).GetMethod("WriteLine", New Type() {GetType(String)}),
                Expression.Constant("Second")
            ),
            Expression.Constant(2)
        )
    }
)

' The following statement first creates an expression tree,
' then compiles it, and then runs it.
Expression.Lambda(Of Action)(switchExpr).Compile()()

' This code example produces the following output:
'
' Second

Remarks

All SwitchCase objects in a SwitchExpression object must have the same type, unless the SwitchExpression has the type void.

Each SwitchCase object has an implicit break statement, which means that there is no implicit fall through from one case label to another.

If switchValue does not match any of the cases, no exception is thrown.

Applies to

Switch(Expression, Expression, SwitchCase[])

Source:: SwitchExpression.cs

Source:: SwitchExpression.cs

Source:: SwitchExpression.cs

Creates a SwitchExpression that represents a switch statement that has a default case.

public:
 static System::Linq::Expressions::SwitchExpression ^ Switch(System::Linq::Expressions::Expression ^ switchValue, System::Linq::Expressions::Expression ^ defaultBody, ... cli::array <System::Linq::Expressions::SwitchCase ^> ^ cases);

public static System.Linq.Expressions.SwitchExpression Switch (System.Linq.Expressions.Expression switchValue, System.Linq.Expressions.Expression defaultBody, params System.Linq.Expressions.SwitchCase[] cases);

public static System.Linq.Expressions.SwitchExpression Switch (System.Linq.Expressions.Expression switchValue, System.Linq.Expressions.Expression? defaultBody, params System.Linq.Expressions.SwitchCase[]? cases);

static member Switch : System.Linq.Expressions.Expression * System.Linq.Expressions.Expression * System.Linq.Expressions.SwitchCase[] -> System.Linq.Expressions.SwitchExpression

Public Shared Function Switch (switchValue As Expression, defaultBody As Expression, ParamArray cases As SwitchCase()) As SwitchExpression

Parameters

switchValue: Expression

The value to be tested against each case.

defaultBody: Expression

The result of the switch if switchValue does not match any of the cases.

cases: SwitchCase[]

The set of cases for this switch expression.

Returns

SwitchExpression

The created SwitchExpression.

Examples

The following example demonstrates how to create an expression that represents a switch statement that has a default case.

// Add the following directive to the file:
// using System.Linq.Expressions;

// An expression that represents the switch value.
ConstantExpression switchValue = Expression.Constant(3);

// This expression represents a switch statement
// that has a default case.
SwitchExpression switchExpr =
    Expression.Switch(
        switchValue,
        Expression.Call(
                    null,
                    typeof(Console).GetMethod("WriteLine", new Type[] { typeof(String) }),
                    Expression.Constant("Default")
                ),
        new SwitchCase[] {
            Expression.SwitchCase(
                Expression.Call(
                    null,
                    typeof(Console).GetMethod("WriteLine", new Type[] { typeof(String) }),
                    Expression.Constant("First")
                ),
                Expression.Constant(1)
            ),
            Expression.SwitchCase(
                Expression.Call(
                    null,
                    typeof(Console).GetMethod("WriteLine", new Type[] { typeof(String) }),
                    Expression.Constant("Second")
                ),
                Expression.Constant(2)
            )
        }
    );

// The following statement first creates an expression tree,
// then compiles it, and then runs it.
Expression.Lambda<Action>(switchExpr).Compile()();

// This code example produces the following output:
//
// Default

' Add the following directive to the file:
' Imports System.Linq.Expressions

' An expression that represents the switch value.
Dim switchValue As ConstantExpression = Expression.Constant(3)

' This expression represents a switch statement 
' that has a default case.
Dim switchExpr As SwitchExpression =
Expression.Switch(
    switchValue,
    Expression.Call(
                Nothing,
                GetType(Console).GetMethod("WriteLine", New Type() {GetType(String)}),
                Expression.Constant("Default")
            ),
    New SwitchCase() {
        Expression.SwitchCase(
            Expression.Call(
                Nothing,
                GetType(Console).GetMethod("WriteLine", New Type() {GetType(String)}),
                Expression.Constant("First")
            ),
            Expression.Constant(1)
        ),
        Expression.SwitchCase(
            Expression.Call(
                Nothing,
                GetType(Console).GetMethod("WriteLine", New Type() {GetType(String)}),
                Expression.Constant("Second")
            ),
            Expression.Constant(2)
        )
    }
)

' The following statement first creates an expression tree,
' then compiles it, and then runs it.
Expression.Lambda(Of Action)(switchExpr).Compile()()

' This code example produces the following output:
'
' Default

Remarks

All SwitchCase objects in a SwitchExpression object must have the same type, unless the SwitchExpression has the type void.

Each SwitchCase object has an implicit break statement, which means that there is no implicit fall through from one case label to another.

If switchValue does not match any of the cases, the default case represented by defaultBody is run.

Applies to

Switch(Expression, Expression, MethodInfo, IEnumerable<SwitchCase>)

Source:: SwitchExpression.cs

Source:: SwitchExpression.cs

Source:: SwitchExpression.cs

Creates a SwitchExpression that represents a switch statement that has a default case.

public:
 static System::Linq::Expressions::SwitchExpression ^ Switch(System::Linq::Expressions::Expression ^ switchValue, System::Linq::Expressions::Expression ^ defaultBody, System::Reflection::MethodInfo ^ comparison, System::Collections::Generic::IEnumerable<System::Linq::Expressions::SwitchCase ^> ^ cases);

public static System.Linq.Expressions.SwitchExpression Switch (System.Linq.Expressions.Expression switchValue, System.Linq.Expressions.Expression defaultBody, System.Reflection.MethodInfo comparison, System.Collections.Generic.IEnumerable<System.Linq.Expressions.SwitchCase> cases);

public static System.Linq.Expressions.SwitchExpression Switch (System.Linq.Expressions.Expression switchValue, System.Linq.Expressions.Expression? defaultBody, System.Reflection.MethodInfo? comparison, System.Collections.Generic.IEnumerable<System.Linq.Expressions.SwitchCase>? cases);

static member Switch : System.Linq.Expressions.Expression * System.Linq.Expressions.Expression * System.Reflection.MethodInfo * seq<System.Linq.Expressions.SwitchCase> -> System.Linq.Expressions.SwitchExpression

Public Shared Function Switch (switchValue As Expression, defaultBody As Expression, comparison As MethodInfo, cases As IEnumerable(Of SwitchCase)) As SwitchExpression

Parameters

switchValue: Expression

The value to be tested against each case.

defaultBody: Expression

The result of the switch if switchValue does not match any of the cases.

comparison: MethodInfo

The equality comparison method to use.

cases: IEnumerable<SwitchCase>

The set of cases for this switch expression.

Returns

SwitchExpression

The created SwitchExpression.

Applies to

Switch(Expression, Expression, MethodInfo, SwitchCase[])

Source:: SwitchExpression.cs

Source:: SwitchExpression.cs

Source:: SwitchExpression.cs

Creates a SwitchExpression that represents a switch statement that has a default case.

public:
 static System::Linq::Expressions::SwitchExpression ^ Switch(System::Linq::Expressions::Expression ^ switchValue, System::Linq::Expressions::Expression ^ defaultBody, System::Reflection::MethodInfo ^ comparison, ... cli::array <System::Linq::Expressions::SwitchCase ^> ^ cases);

public static System.Linq.Expressions.SwitchExpression Switch (System.Linq.Expressions.Expression switchValue, System.Linq.Expressions.Expression defaultBody, System.Reflection.MethodInfo comparison, params System.Linq.Expressions.SwitchCase[] cases);

public static System.Linq.Expressions.SwitchExpression Switch (System.Linq.Expressions.Expression switchValue, System.Linq.Expressions.Expression? defaultBody, System.Reflection.MethodInfo? comparison, params System.Linq.Expressions.SwitchCase[]? cases);

static member Switch : System.Linq.Expressions.Expression * System.Linq.Expressions.Expression * System.Reflection.MethodInfo * System.Linq.Expressions.SwitchCase[] -> System.Linq.Expressions.SwitchExpression

Public Shared Function Switch (switchValue As Expression, defaultBody As Expression, comparison As MethodInfo, ParamArray cases As SwitchCase()) As SwitchExpression

Parameters

switchValue: Expression

The value to be tested against each case.

defaultBody: Expression

The result of the switch if switchValue does not match any of the cases.

comparison: MethodInfo

The equality comparison method to use.

cases: SwitchCase[]

The set of cases for this switch expression.

Returns

SwitchExpression

The created SwitchExpression.

Applies to

Switch(Type, Expression, Expression, MethodInfo, IEnumerable<SwitchCase>)

Source:: SwitchExpression.cs

Source:: SwitchExpression.cs

Source:: SwitchExpression.cs

Creates a SwitchExpression that represents a switch statement that has a default case.

public:
 static System::Linq::Expressions::SwitchExpression ^ Switch(Type ^ type, System::Linq::Expressions::Expression ^ switchValue, System::Linq::Expressions::Expression ^ defaultBody, System::Reflection::MethodInfo ^ comparison, System::Collections::Generic::IEnumerable<System::Linq::Expressions::SwitchCase ^> ^ cases);

public static System.Linq.Expressions.SwitchExpression Switch (Type type, System.Linq.Expressions.Expression switchValue, System.Linq.Expressions.Expression defaultBody, System.Reflection.MethodInfo comparison, System.Collections.Generic.IEnumerable<System.Linq.Expressions.SwitchCase> cases);

public static System.Linq.Expressions.SwitchExpression Switch (Type? type, System.Linq.Expressions.Expression switchValue, System.Linq.Expressions.Expression? defaultBody, System.Reflection.MethodInfo? comparison, System.Collections.Generic.IEnumerable<System.Linq.Expressions.SwitchCase>? cases);

static member Switch : Type * System.Linq.Expressions.Expression * System.Linq.Expressions.Expression * System.Reflection.MethodInfo * seq<System.Linq.Expressions.SwitchCase> -> System.Linq.Expressions.SwitchExpression

Public Shared Function Switch (type As Type, switchValue As Expression, defaultBody As Expression, comparison As MethodInfo, cases As IEnumerable(Of SwitchCase)) As SwitchExpression

Parameters

type: Type

The result type of the switch.

switchValue: Expression

The value to be tested against each case.

defaultBody: Expression

The result of the switch if switchValue does not match any of the cases.

comparison: MethodInfo

The equality comparison method to use.

cases: IEnumerable<SwitchCase>

The set of cases for this switch expression.

Returns

SwitchExpression

The created SwitchExpression.

Applies to

Expression.Switch Method

Definition

Overloads

Switch(Type, Expression, Expression, MethodInfo, SwitchCase[])

Parameters

Returns

Applies to

Switch(Expression, SwitchCase[])

Parameters

Returns

Examples

Remarks

Applies to

Switch(Expression, Expression, SwitchCase[])

Parameters

Returns

Examples

Remarks

Applies to

Switch(Expression, Expression, MethodInfo, IEnumerable<SwitchCase>)

Parameters

Returns

Applies to

Switch(Expression, Expression, MethodInfo, SwitchCase[])

Parameters

Returns

Applies to

Switch(Type, Expression, Expression, MethodInfo, IEnumerable<SwitchCase>)

Parameters

Returns

Applies to

Feedback

Additional resources