表达式树深度的制造&gt成员访问; 1 [英] Expression tree for a member access of depth > 1

问题描述

public class Job
{
    public string Name { get; set; }
    public int Salary { get; set; }
}
public class Employee
{
    public string Name { get; set; }
    public Job Job { get; set; }
}

如果我想创建的一员获得员工的表达式树。名称这是我做的：

If I want to create an expression tree of a member access to Employee.Name this is what I do:

        var param = Expression.Parameter(type, "x");
        var memberAccess = Expression.PropertyOrField(param, memberName);
        return Expression.Lambda<Func<TModel, TMember>>(memberAccess, param);

什么是相当于本作的成员访问Employee.Job.Salary？

What is the equivalent to this for a member access to Employee.Job.Salary ?

推荐答案

您需要：

var jobProperty = Expression.PropertyOrField(param, "Job");
var salaryProperty = Expression.PropertyOrField(jobProperty, "Salary");

基本上你正在做的薪酬属性从评估的结果 x.Job 。

如果你需要做这以编程的方式，你'会需要这样的东西：

If you need to do this in a programmatic way, you'll need something like:

Expression expression = Expression.Parameter(type, "x");
foreach (var property in properties.Split('.'))
{
    expression = Expression.PropertyOrField(expression, property);
}

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