System.Data.DataColumn.HandleDependentColumnList C# (CSharp) Method

        internal void HandleDependentColumnList(DataExpression oldExpression, DataExpression newExpression)
        {
            DataColumn[] dependency;

            // remove this column from the dependentColumn list of the columns this column depends on.
            if (oldExpression != null)
            {
                dependency = oldExpression.GetDependency();
                foreach (DataColumn col in dependency)
                {
                    Debug.Assert(null != col, "null datacolumn in expression dependencies");
                    col.RemoveDependentColumn(this);
                    if (col._table != _table)
                    {
                        _table.RemoveDependentColumn(this);
                    }
                }
                _table.RemoveDependentColumn(this);
            }

            if (newExpression != null)
            {
                // get the list of columns that this expression depends on
                dependency = newExpression.GetDependency();
                // add this column to dependent column list of each column this column depends on
                foreach (DataColumn col in dependency)
                {
                    col.AddDependentColumn(this);
                    if (col._table != _table)
                    {
                        _table.AddDependentColumn(this);
                    }
                }
                _table.AddDependentColumn(this);
            }
        }
    }