/// <summary>
/// Serialize a DataTable to an XmlTextWriter
/// </summary>
/// <param name="tw"></param>
/// <param name="dt"></param>
public void SerializeDataTable(
XmlTextWriter tw,
IDataTableMx iDt)
{
DataTableMx dt = iDt as DataTableMx;
if (dt == null)
{
return; // ignore if no data table
}
tw.WriteStartElement("DataTable");
tw.WriteAttributeString("TableName", dt.TableName);
tw.WriteStartElement("DataColumns");
foreach (System.Data.DataColumn dc in dt.Columns)
{
if (Lex.Eq(dc.ColumnName, RowAttributesColumnName) || // don't include these in output
Lex.Eq(dc.ColumnName, CheckMarkColumnName))
{
continue;
}
tw.WriteStartElement("DataColumn");
tw.WriteAttributeString("ColumnName", dc.ColumnName);
tw.WriteAttributeString("DataType", dc.DataType.FullName);
tw.WriteEndElement();
}
tw.WriteEndElement(); // end of DataColumns
tw.WriteStartElement("DataRows");
foreach (DataRowMx dr in dt.Rows)
{ // put each row in a CData element
object[] oa = dr.ItemArray;
StringBuilder sb = VoArray.SerializeToText(oa, 2, oa.Length - 2);
tw.WriteCData(sb.ToString());
}
tw.WriteEndElement(); // end of DataRows
tw.WriteEndElement(); // end of DataTable
return;
}
/// <summary>
/// Write out rows from table if caching has been activated
/// </summary>
internal void WriteRowsToCache(bool keepLastKeyValue)
{
DataRowMx dr;
string firstKey = "", lastKey = "";
int rowsRemovedInThisCall = 0, ri, ri2, srpi;
if (!AllowCaching)
{
return;
}
if (CacheStartPosition < 0 || CacheWriter == null)
{
return; // just return if caching not active
}
if (DataTableMx.Rows.Count < CacheMiminumRowsRequiredForWriting)
{
return;
}
lock (DataTransferLock) // lock the DataTable while changing
{
if (DataTableFetchPosition < CacheStartPosition)
{
return; // only cache if fetching beyond start position
}
if (DataTableFetchPosition < DataTableMx.Rows.Count - 1)
{
return; // can only cache out if at end of available rows
}
dr = DataTableMx.Rows[CacheStartPosition];
firstKey = dr[KeyValueVoPos] as string;
ri = DataTableMx.Rows.Count - 1;
dr = DataTableMx.Rows[ri];
lastKey = dr[KeyValueVoPos] as string; // key we want to keep
if (QueryManager.MoleculeGrid != null)
{
QueryManager.MoleculeGrid.BeginUpdate();
}
ri = CacheStartPosition; // start deleting here
while (ri < DataTableMx.Rows.Count)
{ // delete anything with key other than end value
dr = DataTableMx.Rows[ri];
string key2 = dr[KeyValueVoPos] as string; // end key with possibly partial data that we want to keep
if (keepLastKeyValue && key2 == lastKey)
{
break;
}
bool doCacheIO = !PurgeDataTableWithoutWritingToCacheFile;
if (doCacheIO)
{
object[] oa = dr.ItemArray;
StringBuilder sb = VoArray.SerializeToText(oa, KeyValueVoPos, oa.Length - KeyValueVoPos);
string lenStr = String.Format("{0,8:00000000}", sb.Length);
CacheWriter.Write(lenStr); // write length
CacheWriter.Write(sb); // write record
RowsWrittenToCache++;
}
DataTableMx.Rows.Remove(dr);
RowsRemovedFromDataTable++;
rowsRemovedInThisCall++;
}
DataTableFetchPosition -= rowsRemovedInThisCall; // adjust fetch position
for (ri2 = CacheStartPosition; ri2 < DataTableMx.Rows.Count; ri2++)
{ // adjust row indexes held the row attributes in rows below those paged out
DataRowAttributes dra = GetRowAttributes(ri2);
if (dra == null)
{
continue;
}
dra.FirstRowForKey -= rowsRemovedInThisCall;
if (dra.SubRowPos == null)
{
continue;
}
for (srpi = 0; srpi < dra.SubRowPos.Length; srpi++)
{
dra.SubRowPos[srpi] -= rowsRemovedInThisCall;
}
}
} // end of locked section
if (QueryManager.MoleculeGrid != null)
{
QueryManager.MoleculeGrid.EndUpdate();
QueryManager.MoleculeGrid.Refresh();
Application.DoEvents();
}
if (DebugCaching)
{
ClientLog.Message(
"CachedRows - DataTable.Rows.Count: " + DataTableMx.Rows.Count +
", FirstKey: " + firstKey + ", LastKey: " + lastKey +
", RowsRemovedFromDataTable (This Call): " + rowsRemovedInThisCall +
", RowsRemovedFromDataTable (Total): " + RowsRemovedFromDataTable +
", RowsWrittenToCache (Total): " + RowsWrittenToCache +
", DataTableFetchPosition: " + DataTableFetchPosition);
}
return;
}