如何在运行时构建一个范围切换大小写表达式?[复制品]

您可以使用其他重载来简化代码 Expression.SwitchCase

只需创建一个带有测试值的数组并将其转换为 ConstantExpression . 试试这个例子:

var writeLine = typeof(Console).GetMethod("WriteLine", new[] {typeof(string)});

// body of first block
var action1 = Expression.Call(writeLine, Expression.Constant("1 or 2"));
// body of second block
var action2 = Expression.Call(writeLine, Expression.Constant("3, 4 or 5"));

var value = Expression.Parameter(typeof(int), "value");
var body = Expression.Switch(value,
    Expression.SwitchCase(
      action1,
      new[] {1, 2}.Select(i => Expression.Constant(i))),
    Expression.SwitchCase(
      action2, 
      new[] {3, 4, 5}.Select(i => Expression.Constant(i)))
);

var lambda = Expression.Lambda<Action<int>>(body, value);
var method = lambda.Compile();

method(1); // print "1 or 2"
method(4); // print "3, 4 or 5"