CODEWITHSUNDEEP
c#
SkyDrive
SkyDrive

Reputation: 1455

Change value of member of class which is contained in the list

I have this class Variables 

public class Variables
{

    public enum DataType
    {
        INT, CHAR, BOOL, FLOAT
    }

    public string Name { get; set; }
    public DataType Type { get; set; }
    public object Value { get; set; }

    public Variables(string name, DataType type, object value)
    {
        Name = name;
        Type = type;
        Value = value;
    }

}

It is also assumed that Name is unique. And inside another class I have a list of variables, List<Variables>

public void Main()
{
    List<Variables> varList = new List<Variables>();
    varList.Add(new Variables("x",DataType.BOOL, true));
    varList.Add(new Variables("y",DataType.BOOL, false));
    varList.Add(new Variables("z",DataType.BOOL, true));
    varList.Add(new Variables("a",DataType.INT, 1));
    varList.Add(new Variables("b",DataType.INT, 10));

    // I need this to convert into LiNQ.
    foreach (Variables _x in varList)
    {
        if (_x.Name == "z")
        {
            _x.Value = false;
        }
    }
}

How can I convert foreach into LiNQ? I tried .Where, .Select but they return IEnumerable. Is there a LinQ method that returns only a single value that matches to a given condition? eg,

Variables _var = varList.MethodName(LambDa Expression).....

Upvotes: 1

Views: 77

Answers (3)

Aghilas Yakoub
Aghilas Yakoub

Reputation: 28980

You can use also First

varList.First(a => a.Name == "z").Value = false;

Upvotes: 1

Erix
Erix

Reputation: 7105

var variablesInstance = varList.Where(v => v.Name == "z").FirstOrDefault();
if(variablesInstance != null)
{
    variablesInstance.Value = false;
}

You can use First instead of FirstOrDefault if you know the thing exists with that name.

Upvotes: 2

Jon Skeet
Jon Skeet

Reputation: 1500875

Well you can use Single:

varList.Single(x => x.Name == "z").Value = false;

That will fail if there's anything other than exactly one match though.

Alternatives are SingleOrDefault, FirstOrDefault, First, LastOrDefault and Last. For example, if you expect "0 or 1" results:

var match = varList.SingleOrDefault(x => x.Name == "z");
if (match != null)
{
    match.Value = false;
}

Upvotes: 3

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