在带有分组的列表上创建字典 [英] Create a dictionary on a list with grouping

问题描述

我在列表中有以下对象:

I have the following object in a list:

public class DemoClass
{
    public int GroupKey { get; set; }
    public string DemoString { get; set; }
    public object SomeOtherProperty { get; set; }
}

现在，我想从中创建以下字典:

Now, I want to create following dictionary out of it:

Dictionary<int, List<DemoClass>>

我想通过属性 GroupKey 对 List 进行分组，但我不明白这是如何完成的以及一些帮助.

I want to group the List<DemoClass> by the property GroupKey, but I don't understand how this is done and some help.

经过深思熟虑后，我通过以下方式实现了所需的行为:

After thinking a bit, I achieved the needed behaviour with:

var groupedDemoClasses = from demoClass in mySepcialVariableWhichIsAListOfDemoClass
                            group demoClass by demoClass.GroupKey
                            into groupedDemoClass
                            select groupedDemoClass;
var neededDictionary = groupedDemoClass.ToDictionary(gdc => gdc.Key, gdc => gdc.ToList());

但是，有没有办法把它变成一个单独的语句?

but, is there a way to make this into a single statement?

推荐答案

var groupedDemoClasses = (from demoClass in mySepcialVariableWhichIsAListOfDemoClass
                          group demoClass by demoClass.GroupKey
                          into groupedDemoClass
                          select groupedDemoClass).ToDictionary(gdc => gdc.Key, gdc => gdc.ToList());

这个可以用！！！

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