I am a danish programmer living in Bangkok.
Read more about me @ rasmus.rummel.dk.

DataTable Get SubHierarchy

Usage

Example
- In my Discussions WebControl I need to calculate how many discussions there are collectively under a category, which I do by using GetSubHierarchy to find the whole sub hierarchy of categories and count direct discussions under each category.

Example Code

DataTable myTable = GetData(); //your custom function
DataTable dtSubHierarchy = Utils.DataTable.GetSubHierarchy(myTable, 8, "ID", "PID", "SortOrder");

dtSubHierarchy now contains the sub hierarchy recursively ordered starting from node with ID=8.

The GetSubHierarchy function :

public static DataTable GetSubHierarchy(DataTable pdtSource, int pIDValue, string pIDColumn, string pPIDColumn, string pSortColumn)
{
	DataTable dtResult = pdtSource.Clone();
 
	pdtSource.PrimaryKey = new DataColumn[] { pdtSource.Columns[pIDColumn] };
 
	DataRow drCurrent = pdtSource.Rows.Find(pIDValue);
 
	if (drCurrent != null)
	{
		dtResult.Rows.Add(drCurrent.ItemArray);
 
		DataView dv = new DataView(pdtSource);
		dv.RowFilter = pPIDColumn + " = " + pIDValue;
		dv.Sort = pSortColumn;
 
		foreach (DataRowView drv in dv)
		{
			dtResult.Rows.Add(drv.Row.ItemArray);
 
			int currentID = (int)drv[pIDColumn];
			GetSubHierarchyHelper(pdtSource, ref dtResult, currentID, pIDColumn, pPIDColumn, pSortColumn);
		}
	}
 
	return dtResult;
}
private static void GetSubHierarchyHelper(DataTable pdtSource, ref DataTable pdtResult, int pIDValue, string pIDColumn, string pPIDColumn, string pSortColumn)
{
	DataView dv = new DataView(pdtSource);
	dv.RowFilter = pPIDColumn + " = " + pIDValue;
	dv.Sort = pSortColumn;
 
	foreach (DataRowView drv in dv)
	{
		pdtResult.Rows.Add(drv.Row.ItemArray);
 
		int currentID = (int)drv[pIDColumn];
		GetSubHierarchyHelper(pdtSource, ref pdtResult, currentID, pIDColumn, pPIDColumn, pSortColumn);
	}
}