Expression.SwitchCase Method (Expression, IEnumerable<Expression>)

Creates a SwitchCase object to be used in a SwitchExpression object.

Namespace:  System.Linq.Expressions
Assemblies:   System.Core (in System.Core.dll)
  System.Linq.Expressions (in System.Linq.Expressions.dll)

public static SwitchCase SwitchCase(
	Expression body,
	IEnumerable<Expression> testValues
)

Parameters

body
Type: System.Linq.Expressions.Expression

The body of the case.

testValues
Type: System.Collections.Generic.IEnumerable<Expression>

The test values of the case.

Return Value

Type: System.Linq.Expressions.SwitchCase
The created SwitchCase.

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.

The following example demonstrates how to create an expression that represents a swtich 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

.NET Framework

Supported in: 4.6, 4.5, 4

.NET Framework Client Profile

Supported in: 4

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Store apps

Supported in: Windows 8

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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