/// <summary>
/// Reads data using DDE. This is extremely show and should only ever be used as a last resort.
/// </summary>
/// <param name="mocktables"></param>
internal void GetDataByDDE(List <TableDef> mocktables) // needs fixing
{
/* DDE requests are limited to a maximum length of 255 characters,
* which is easily exceeded. A workaround is splitting the requests.
* Not pretty but the only way to get to many-many relationships that contain >93750 worth of connected characters
* without setting the maxfieldsize higher.
*/
List <List <CommenceValue> > rows;
List <CommenceValue> rowvalues;
ICommenceDatabase db = new CommenceDatabase();
// always define a category
db.ViewCategory(this.cursor.Category);
// are we dealing with a view?
if (!string.IsNullOrEmpty(cursor.View))
{
db.ViewView(this.cursor.View);
}
int itemCount = db.ViewItemCount();
for (int i = 1; i <= itemCount; i++) // note that we use a 1-based iterator
{
rows = new List <List <CommenceValue> >();
rowvalues = new List <CommenceValue>();
foreach (TableDef td in mocktables)
{
string[] DDEResult = null;
List <string> fieldNames = td.ColumnDefinitions.Select(o => o.FieldName).ToList();
if (td.Primary)
{
// ViewFields and ViewConnectedFields have a limited capacity
// the total length of a DDE command cannot exceed 255 characters
// What we are going to do is limit the number of characters to a value of up to 150 chars,
// to be on the safe side (ViewConnectedFilter and two delimiters already make up 35 characters!)
ListChopper lcu = new ListChopper(fieldNames, 150);
foreach (List <string> l in lcu.Portions)
{
DDEResult = db.ViewFields(i, l);
// we have our results, we now have to create CommenceValue objects from it
// and we also have to match them up with their respective column
// this is a little tricky...
for (int j = 0; j < DDEResult.Length; j++)
{
ColumnDefinition cd = td.ColumnDefinitions.Find(o => o.FieldName.Equals(l[j]));
string[] buffer = new string[] { DDEResult[j] };
//buffer = FormatValues(buffer,this.Formatting, cd);
buffer = FormatValues(buffer, cd);
CommenceValue v = new CommenceValue(buffer[0], cd);
rowvalues.Add(v);
} // for
} // list l
}
else // we are dealing with a connection
{
int conItemCount = db.ViewConnectedCount(i, td.ColumnDefinitions[0].Connection, td.ColumnDefinitions[0].Category); // doesn't matter which one we use
// here's a nice challenge:
// upon every iteration we get a row of fieldvalues from the connection
// to make things worse, we chop them up so it aren't even complete rows.
// we must aggregate the values for each field.
// We'll construct a datatable to hack around that;
// we could have also used a dictionary I suppose.
// using a datatable may be easiest
DataTable dt = new DataTable();
for (int c = 0; c < fieldNames.Count; c++)
{
dt.Columns.Add(fieldNames[c]); // add fields as columns, keeping everything default
}
// loop all connected items
for (int citemcount = 1; citemcount <= conItemCount; citemcount++)
{
DataRow dr = dt.NewRow(); // create a row containing all columns
ListChopper lcu = new ListChopper(fieldNames, 150);
foreach (List <string> list in lcu.Portions)
{
DDEResult = db.ViewConnectedFields(i, td.ColumnDefinitions[0].Connection, td.ColumnDefinitions[0].Category, citemcount, list);
// populate colums for the fields we requested
for (int j = 0; j < DDEResult.Length; j++)
{
dr[list[j]] = DDEResult[j];
}
} // list l
dt.Rows.Add(dr);
} // citemcount
// create a CommenceValue from every column in the datatable
foreach (DataColumn dc in dt.Columns)
{
// this will also return columns that have no data, which is what we want.
string[] query =
(from r in dt.AsEnumerable()
select r.Field <String>(dc.ColumnName)).ToArray();
ColumnDefinition cd = td.ColumnDefinitions.Find(o => o.FieldName.Equals(dc.ColumnName));
CommenceValue cv = null;
if (query.Length > 0) // only create value if there is one
{
//query = FormatValues(query, this.Formatting, cd);
query = FormatValues(query, cd);
cv = new CommenceValue(query, cd);
}
else
{
// create empty CommenceValue
cv = new CommenceValue(cd);
}
rowvalues.Add(cv);
}
} // if
} // foreach tabledef
rows.Add(rowvalues);
CursorDataReadProgressChangedArgs args = new CursorDataReadProgressChangedArgs(rows, i, totalRows); // progress within the cursor
OnDataProgressChanged(args);
} // i
db = null;
ExportCompleteArgs a = new ExportCompleteArgs(itemCount);
OnDataReadCompleted(a);
}