Recursive Linq query

[Ujjwal Manna]

Hi All,

Presently I am stuck in a linq query. It would be great if you can help on this.

My Sql table looks like this:
NameId
ParentNameId
Name

Now I have to write a query where user will give the Name as input and I have to return all the parents up to the root NameId.
[ex :
     Ujjwal
        Ram
           Andy
             Bob
         Sam
             Mathew

Now if user give the input as "Andy". I have to return the result from linq query which contain below information :

  Ujjwal
     Ram
       Andy

Thanks in advance for your help.

Regards,
Ujjwal

 

[Damyan Bogoev]

Hello Ujjwal Manna,

Unfortunately the Linq framework does not support recursive queries yet and you will have to use a recursive method which contains a Linq query. This method would look similar to this:

public void Walker(IObjectScope scope, string names)
{
 var nameList = scope.Extent<Name>().Where(n => n.Names == names);
 foreach (var name in nameList)
 {
  if (name != null)
  {
   Console.WriteLine(name.Names);
   if (name.ParentNameId != null)
   {
    Walker(scope, name.Name1.Names);
   }
  }
 }
}

Hope that helps.

Best wishes,
Damyan Bogoev
the Telerik team

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[Ujjwal Manna]

Hi All,
Thanks a lot for your kind help. I need one more help from you. Now I want to write one more linq query where it will return all the records including its children.

For example :

Ujjwal
        Ram
           Andy
                Bob
                  Jim
            Das
               Merry
         Sam
             Mathew

For the above structure  I have to write a function where I will pass the id of the Parent node and it will return all childrens which is belongs to that parent. Now if I pass the id of "Ram" it will return the results like below :

    Ram
           Andy
                Bob
                  Jim
            Das
               Merry

I have already tried with different approch but nothing works properly,so it would be greate if you can help on this or if you can send me any link.

Regards,
Ujjwal

[Damyan Bogoev]

Hi Ujjwal Manna,

You could use the following method in order to achieve the inquired traversal:

public void TraverseChilds(IObjectScope scope, string names)
{
    Console.WriteLine(names);
    var childList = scope.Extent<Name>().Where(n => n.ParentReference.Names == names);
    foreach (var name in childList)
    {
        if (name != null)
        {
            TraverseChilds(scope, name.Names);
        }
    }
}

I think that will help you.

Greetings,
Damyan Bogoev
the Telerik team

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