下面工作的code，但我想介绍一个 ToUpper的（）

The code below work, but I'd like introduce a ToUpper()

var predicate =
    Expression.Lambda<Func<T, bool>>(
        Expression.Call(
            Expression.PropertyOrField(parameter, "FirstName"),
            "Contains", null,
            Expression.Constant("myvalue".ToUpper())), parameter
        );

结果是：

{Param_0 => Param_0.FirstName.Contains("MYVALUE")}

不过，我想这样的：

But I'd like this :

{Param_0 => Param_0.FirstName.ToUpper().Contains("MYVALUE")}

我如何更改？

How can I change ?

推荐答案

只需添加一个防爆pression.Call ：

var predicate =
    Expression.Lambda<Func<T, bool>>(
        Expression.Call(
            Expression.Call( // <=== this one is new
                Expression.PropertyOrField(parameter, "FirstName"),
                "ToUpper", null),
            "Contains", null,
            Expression.Constant("myvalue".ToUpper())), parameter
        );

然后自己报告如下：

which then reports itself as:

Param_0 => Param_0.FirstName.ToUpper().Contains("MYVALUE")