Converting List into custom objects

Question

I am reading an XML document using the XDocument library and querying into a list with LINQ in C#. I am returning an anoymous list into an implicit var. The anynmous type is a simple structure. I am not sure what I am doing wrong but would like to return this into a List of a class I already defined but am getting an error converting this anonymous type into my custom class. Am I missing something obvious on this on. I do not want to use dynamic typing here.

public class CustomClass
    {
        public string id { get; set; }
        public int fileName { get; set; }
    }

XDocument optXML = XDocument.Load(pathName);

var optInput = (from item in optXML.Descendants("Group")
                    select new
                    {
                        id = (int)item.Attribute("ID"),
                        fileName = (string)item.Attribute("FileName")
                    }).ToList();
foreach (CustomClass item in optInput)
        {
            Console.WriteLine(item.id);
        }

Fede · Accepted Answer · 2012-12-18 16:36:44Z

4

Instead of selecting a new{} select a new CustomClass():

public class CustomClass
    {
        public string id { get; set; }
        public int fileName { get; set; }
    }

XDocument optXML = XDocument.Load(pathName);

var optInput = (from item in optXML.Descendants("Group")
                    select new CustomClass()
                    {
                        id = (int)item.Attribute("ID"),
                        fileName = (string)item.Attribute("FileName")
                    }).ToList();
foreach (CustomClass item in optInput)
        {
            Console.WriteLine(item.id);
        }

answered Dec 18, 2012 at 16:36

Fede

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Comments

Jamiec · Accepted Answer · 2012-12-18 16:37:01Z

2

I think you want to project into CustomClass rather than an anonymous object

List<CustomClass> optInput = (from item in optXML.Descendants("Group")
                select new CustomClass 
                {
                    id = (int)item.Attribute("ID"),
                    fileName = (string)item.Attribute("FileName")
                }).ToList();

There's no specific reason to change var in your code to List<CustomClass> - ive just done it to demonstrate to you what you're actually getting.

answered Dec 18, 2012 at 16:37

Jamiec

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Comments

Adil · Accepted Answer · 2012-12-18 16:35:56Z

1

You can use var instead of custom type, it will be the type generated by the compiler in your projection use new.

foreach (var item in optInput)
{
     Console.WriteLine(item.id);
}

or you can create object of your class i.e CustomClass instead of using anonymous type.

  var optInput = (from item in optXML.Descendants("Group")
                select new CustomClass 
                {
                    id = (int)item.Attribute("ID"),
                    fileName = (string)item.Attribute("FileName")
                }).ToList();

answered Dec 18, 2012 at 16:35

Adil

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1 Comment

JBone Over a year ago

Is there a way to import directly into the custom class like List<CustomClass> = (from item in optXML.Descendants("Group") select new { id = (int)item.Attribute("ID"), fileName = (string)item.Attribute("FileName") }).ToList();

Ani · Accepted Answer · 2012-12-18 16:38:00Z

1

You're getting this error because the anonymous type you select inside your query is NOT CustomClass. You can simply select Customclass itself like so

    select new CustomClass { id = , fileName = }

or use the anomymous type like so inside the foreach

    foreach (var item in optInput) 
    { 
        Console.WriteLine(item.id); 
    }

and you'll get full intellisense for it.

answered Dec 18, 2012 at 16:38

Ani

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