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Expression.Switch Method (Expression, SwitchCase[])

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

Namespace:  System.Linq.Expressions
Assembly:  System.Core (in System.Core.dll)
public static SwitchExpression Switch(
	Expression switchValue,
	params SwitchCase[] cases
)

Parameters

switchValue
Type: System.Linq.Expressions.Expression

The value to be tested against each case.

cases
Type: System.Linq.Expressions.SwitchCase[]

The set of cases for this switch expression.

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.

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

.NET Framework

Supported in: 4.5.1, 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

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

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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