与分组列表上创建一个字典 [英] Create a dictionary on a list with grouping

问题描述

我有一个列表中的下列对象：

 公共类DemoClass
{
    公众诠释GroupKey {获得;组; }
    公共字符串DemoString {获得;组; }
    公共对象SomeOtherProperty {获得;组; }
}
 

现在，我想创建以下字典出来的：

 词典＆LT; INT，名单，其中，DemoClass＆GT;＆GT;
 

我想组名单，其中，DemoClass＆GT; 由酒店 GroupKey ，但我不明白怎么做到这一点，并有所帮助。

想了一下后，我和取得所需的行为：

  VAR groupedDemoClasses =从demoClass在mySepcialVariableWhichIsAListOfDemoClass
                            组demoClass由demoClass.GroupKey
                            进入groupedDemoClass
                            选择groupedDemoClass;
变种neededDictionary = groupedDemoClass.ToDictionary（GDC =＆GT; gdc.Key，GDC =＆GT; gdc.ToList（））;
 

不过，是有办法使它成为一个单独的语句？

解决方案

  VAR groupedDemoClasses =（从demoClass在mySepcialVariableWhichIsAListOfDemoClass
                          组demoClass由demoClass.GroupKey
                          进入groupedDemoClass
                          选择groupedDemoClass）.ToDictionary（GDC =＆GT; gdc.Key，GDC =＆GT; gdc.ToList（））;
 

这人会工作！

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; }
}

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

Dictionary<int, List<DemoClass>>

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

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());

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

解决方案

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

This one will work !!!

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