Working with compact sql in background thread creates memory problems

[dseaver]

I am working creating a program in VS2005 which creates, populates and queries a Sql Server Compact Edition database. I am threading the sql queries and excel and Pdf generation so that the GUI doesn't lock up. I was debugging the functions for querying and report generation without threading the methods, but as soon as I moved the methods to a background worker, I started getting the following exception: "Attempted to read or write protected memory. This is often an indication that other memory is corrupt."

When I populate the DB in a thread it works fine, but when I switch to a different thread and try to execute the exception when I run the fill method ("resultAdapt.Fill(resultTable);"). The methods worked fine when it wasn't threaded.

here is a partial stack trace

System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
   at System.Data.SqlServerCe.NativeMethods.Move(IntPtr pSeCursor, DIRECTION direction, IntPtr pError)
   at System.Data.SqlServerCe.SqlCeDataReader.Move(IntPtr pSeCursor, DIRECTION direction)
   at System.Data.SqlServerCe.SqlCeDataReader.Move(DIRECTION direction)
   at System.Data.SqlServerCe.SqlCeDataReader.Read()
   at System.Data.Common.DataAdapter.FillLoadDataRow(SchemaMapping mapping)
   at System.Data.Common.DataAdapter.FillFromReader(DataSet dataset, DataTable datatable, String srcTable, DataReaderContainer dataReader, Int32 startRecord, Int32 maxRecords, DataColumn parentChapterColumn, Object parentChapterValue)
   at System.Data.Common.DataAdapter.Fill(DataTable[] dataTables, IDataReader dataReader, Int32 startRecord, Int32 maxRecords)
   at System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior)
   at System.Data.Common.DbDataAdapter.Fill(DataTable[] dataTables, Int32 startRecord, Int32 maxRecords, IDbCommand command, CommandBehavior behavior)
   at System.Data.Common.DbDataAdapter.Fill(DataTable dataTable)

I tried googling the exception and found nothing that would fix the problem

 

[AlexCuse]

Can you post your code?



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[dseaver]

I found the problem, I was still calling the method in the main thread and then calling it in the background thread, causing a collision.

 

[AlexCuse]

Figured it was something along those lines. Glad you got it sorted

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