get a particular property value using Linq to C#

Question

I created a class with properties like this

public class Dependencies
{
    public string issueID { get; set; }
    public string status { get; set; }
    public int dependencyCheck { get; set; }
}

Now I created a method where i can use these properties.

private static void prepareIssuesList(string IssueKey, string JIRAtoken)
{
    Dependencies dpObj = new Dependencies();
    List<Dependencies> listObj = new List<Dependencies>();
    dpObj.issueID = IssueKey;
    dpObj.status = "open";
    dpObj.dependencyCheck = 0;
    listObj.Add(dpObj);

}

Now my question is, how to change the dependencyCheck property value. The prepareIssuesList() can called for multiple times. So i am adding multiple objects to Dependencies class. At certain point of time i want to change the dependencyCheck property value. How to do this. I think need to use the Linq to C#. ICan any one have any solution for this one?

what do you mean, "change the dependencyCheck property value"? You just have to assign it... Linq has nothing to do with it — Thomas Levesque, Jun 13 '12 at 12:09
your `listObj` seems to be not stored at all, so each time you call `preapreIssuesList`, it's going to be a _new_ one, right? — Vlad, Jun 13 '12 at 12:09
No idea what you are trying to do... but you should name classes like that as singular (i.e. "Dependency") to make the code more understandable — musefan, Jun 13 '12 at 12:10
This code doesn't seem complete. prepareIssuesList() is creating a local list and never returning it or saving it anywhere. — Jon Senchyna, Jun 13 '12 at 12:10
Why is this downvoted? How about we all allow the non-native english speaker to try to explain her/his problem first? — vgru, Jun 13 '12 at 12:11
You can use LINQ. This thread might helpful for you http://stackoverflow.com/questions/1175645/find-an-item-in-list-by-linq — Muneer, Jun 13 '12 at 12:12
@Groo I down-voted it for the same reason that I voted to close it for *not being a real question*. — Klaus Byskov Pedersen, Jun 13 '12 at 12:13
Sorry all, it is not storing those values. I thought it may store. How to store those added values. I am not getting any idea. — Searcher, Jun 13 '12 at 12:18
Where is `preapreIssuesList` called? Can you show that code snippet? — vgru, Jun 13 '12 at 12:24
I am calling it in another method. Very big to fit here. I just give you the method definition in which i am calling. internal static ChangeSetData getChangeSet(string issuekey,string jiratoken){ prepareIssueList(issuekey, jiratoken) } — Searcher, Jun 13 '12 at 12:33

score 4 · Accepted Answer · answered Jun 13 '12 at 12:28

4

I would do something along these lines:

public class Dependency
{
     public string IssueId { get; set; }
     public string Status { get; set; }
     public int DependencyCheck { get; set; }
}

public class DependencyManager
{
     public DependencyManager()
     {
          this.Dependencies = new List<Dependency>();
     }         

     public List<Dependency> Dependencies { get; private set; }

     public void AddDependency(string issueId)
     {
         var dep = new Dependency();
         dep.IssueId = issueId;
         dep.Status = "open";
         dep.DependencyCheck = 0;

         this.Dependencies.Add(dep);
     }

     public void SetDependencyCheck(string issueId, int value)
     {
         var dep = this.FindDependencyByIssueId(issueId);
         dep.DependencyCheck = value;
     }

     public Dependency FindDependencyByIssueId(string issueId)
     {
         var dep = this.Dependencies.FirstOrDefault(d => d.IssueId.Equals(issueId));
         if(dep == null) throw new ArgumentException("Dependency not found", "issueId");
         return dep;
     }
}

Then somewhere in your code you could do:

var mgr = new DependencyManager();
mgr.AddDependency("ABC123");
mgr.AddDependency("ABC456");

//... some other stuff that makes sense

mgr.SetDependecyCheck("ABC123", 42);

answered Jun 13 '12 at 12:28

Klaus Byskov Pedersen

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+1 Although it would be worthy explaining why OP's code didn't work (because a new `List` instance was being created on each call). – vgru Jun 13 '12 at 12:30
@Klaus.. Thanks. Really I am feeling so much shy that i dont know that how to code like this.. really awesome. – Searcher Jun 13 '12 at 12:41
@YSSS You are welcome. Just keep practicing and asking questions here and your skills will definitely improve with time. – Klaus Byskov Pedersen Jun 13 '12 at 12:44
@KlausByskovHoffmann the code what you present here also not storing values. – Searcher Jun 13 '12 at 13:16
@YSSS hehe ok. I think you are not aware of when values are stored and when not. As long as the `mgr` instance is in scope, it holds all the values you put into it. When the `mgr` runs out of scope it gets "lost". Since I don't know the structure of your code, I cannot recommend how to best store the instance. – Klaus Byskov Pedersen Jun 13 '12 at 13:20
@YSSS DependencyManager keeps a Property called `Dependencies` that is used to store the `Dependency` objects. – Jon Senchyna Jun 13 '12 at 13:21
What I done is, I kept in another function your second block of code. Means var mgr = new DepedencyManager().. etc Kept in prepareIssueList function. I am calling twice in my program. Old values are not retaining. – Searcher Jun 13 '12 at 13:28
@YSSS that is not the right thing to do. You need to have **only one** instance of the `DependencyManager`. You can't just create a new one and expect it to keep the values (how would that work, anyway?). In the class that has your `prepareIssueList` function make a property/field that holds the instance of the `DependencyManager` and use that instance in the function. The easiest way would be: `private DepencyManager myManager = new DependecyManager();`. Now in `prepareIssueList` you use `myManager`. – Klaus Byskov Pedersen Jun 13 '12 at 13:32
Where to wirte the private DependancyManager myManger = new DependencyManager(); ? In DependancyManager class? – Searcher Jun 13 '12 at 13:37
If possible can you make changes to the your suggested code related to your suggestion!! – Searcher Jun 13 '12 at 13:38
@YSSS **In the class that has your prepareIssueList function** – Klaus Byskov Pedersen Jun 13 '12 at 13:43

get a particular property value using Linq to C#

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