The Expression.Switch creates a SwitchExpression that represents a switch statement that has a default case.
For example, you have the following code.
int value = 4;
switch (value)
{
case 1:
Console.WriteLine("First Case");
break;
case 2:
Console.WriteLine("Second Case");
break;
case 3:
Console.WriteLine("Third Case");
break;
default:
Console.WriteLine("Default Case");
break;
}
Here is the code that is required to build the same functionality using expression tree.
ConstantExpression switchValue = Expression.Constant(4);
var defaultCase = WriteLineExpression("Default Case");
var case1 = WriteLineExpression("First Case");
var case2 = WriteLineExpression("Second Case");
var case3 = WriteLineExpression("Third Case");
// This expression represents a switch statement
// that has a default case.
SwitchExpression switchExpr =
Expression.Switch(
switchValue,
defaultCase,
new SwitchCase[]
{
Expression.SwitchCase(case1,Expression.Constant(1)),
Expression.SwitchCase(case2,Expression.Constant(2)),
Expression.SwitchCase(case3,Expression.Constant(3))
}
);
Expression.Lambda<Action>(switchExpr).Compile()();