DataTable to TreeView in C#, Displaying Hierarchies
In this article I will show you how to display hierarchies in a TreeView control, when your data is in a DataTable. In this example we have an Employee table with 3 columns: ID, ParentID and Name. ParentID is the ID of the boss for the current Employee. The first step is to sort the table by the ParentID . This step is really important because we cannot insert a node in the tree until it's parent is not inserted. Notice the root of the tree having a ParentID of -1. Here is the code for this: The second step is to use a XmlDocument. The TreeView control does not have the functionality to find an arbitrary node given a node ID. A recursive find function seems to be too much hassle, not to mention the performance, so I decided to take advantage of the XPath search capabilities of XmlDocument to find a given Parent node. Here is the code for this: The third step is to hook up our data to the TreeView. If you try to bind the TreeView control to an XmlDocument you w...
