Binding treeView with recursion

You can put all the data into class like in your case
class CategoryCalss{public string idCat;public string nameCat}
class suCateClass{public string idSubCat;public string nameSubCat;public string idCat}
class ArticClass{public string idArt, public string name, public string idSubCat}

Get the Data and Fill the data to the respective class and form as List<category>, List<su.....,>
Then you can use the following code
TreeNode treeNodeParent = new TreeNode();
TreeNode treeNodeChd = new TreeNode();
foreach(CategoryClass cat in catList)
{
treeNodeChd = new TreeNode();
treeNodeChd=getsubDir(cat);
treeNodeParent.ChildNodes.Add(treeNodeChd);
}
TreeView1.Nodes.Add(treeNodeParent);

public TreeNode getSubCat(CategoryClass cat)
{
IEnumerable<subcatclass> subcatQuery= from subCa in subcatList where subCa.idCat=cat.idCat select subCa;
TreeNode par=new TreeNode();
TreeNode Chd=new TreeNode();
foreach(SubCatclass sub in subcatquery){
chd=new TreeNode();
chd=getArtl(sub);
chd.Text=sub.name;
par.ChildNodes.Add(chd);
}
return par;
}

public TreeNode getArtl(subcatClass cat)
{
IEnumerable<artlclass> artlQuery= from artl in ArtlList where artl.idCat=cat.idsubCat select artl;
TreeNode par=new TreeNode();
TreeNode Chd=new TreeNode();
foreach(ArtlClass art in artlQuery){
chd=new TreeNode();
chd.Text=art.name;
par.ChildNodes.Add(chd);
}
return par;
}

The above is the rough code I have return. This should be helpful for you.