C# - doppelte Zeilen aus DataTable löschen

/// <summary>
/// Removes duplicate rows in a DataTable.
/// </summary>
/// <param name="dataTable">The DataTable.</param> 
/// <param name="columnName">Name of the column</param>
private static void RemoveDuplicateRows(DataTable dataTable, string columnName) 
{
    Hashtable hashTable = new Hashtable();
    List<DataRow> duplicateList = new List<DataRow>();
    foreach (DataRow dataRow in dataTable.Rows)
        try
        {
            hashTable.Add(dataRow[columnName], string.Empty);
        }
        catch
        {
            duplicateList.Add(dataRow);
        }
    foreach (DataRow dataRow in duplicateList)
        dataTable.Rows.Remove(dataRow);
}