public ColumnIndex GetIndex(int columnOffset)
{
AssertNotDisposed();
if (columnOffset < 0 || columnOffset >= ColumnCount)
{
throw new ArgumentOutOfRangeException("columnOffset");
}
var index = columnIndexes[columnOffset];
// Cache the scheme in this object.
if (index == null)
{
index = TableSource.CreateColumnIndex(indexSet, this, columnOffset);
columnIndexes[columnOffset] = index;
}
// Update the underlying scheme to the most current version.
EnsureColumnIndexCurrent(columnOffset);
return(index);
}