LINQ custom class query with parameters select-CodePudding

I need to get a linq querry for custom class MyFileData

public class MyFileData 
{
private string name;
private string last_mod;
private string file_type;
private long size;

public string Name
{
    get { return name; }
    set { name = value; }
}

public string LastMod
{
    get { return last_mod; }
    set { last_mod = value; }
}

public long Size
{
    get { return size; }
    set { size = value; }
}

public string FileType
{
    get { return file_type;}
    set { file_type = value; }
}

}

but I want as an output values of all properties without file_type like this

from file in files
    select new MyFileData
    {
        Name = file.Name,
        LastMod = file.LastMod,
        Size = file.Size,
    };

so the output without the "fileType"

[{"name":"desktop.ini","lastMod":"07.12.2019 10:12:42","size":174,"fileType":null}]

in this way

[{"name":"desktop.ini","lastMod":"07.12.2019 10:12:42","size":174}]

also I would like to group the files with the type of the extenstion like that

from file in files
group file by file.FileType;

but it gives an error.

The files is IEnumerable<MyFileData> type.

CodePudding user response：

In a simple way, you can try to use an anonymous class

files.Select(x=> new { 
    Name = x.Name,
    LastMod = x.LastMod,
    Size = x.Size
});

but I would create another class that carries you expect property as a ViewModel.

CodePudding user response：

You could try to set null value handling in the JsonProperty attribute. Setting NullValueHandling = NullValueHandling.Ignore makes null values ignored when serializing or deserializing objects.

[JsonProperty("fileType", NullValueHandling = NullValueHandling.Ignore)]
public string FileType
{
    get { return file_type;}
    set { file_type = value; }
}