DbDataReader ExecuteResultSetReader(ViewPage page)
{
if (_serverRules.ResultSet == null)
return null;
SelectClauseDictionary expressions = new SelectClauseDictionary();
foreach (DataColumn c in _serverRules.ResultSet.Columns)
expressions[c.ColumnName] = c.ColumnName;
if (page.Fields.Count == 0)
{
PopulatePageFields(page);
EnsurePageFields(page, null);
}
DataView resultView = new DataView(_serverRules.ResultSet);
resultView.Sort = page.SortExpression;
using (DbConnection connection = CreateConnection(false))
{
DbCommand command = connection.CreateCommand();
StringBuilder sb = new StringBuilder();
_resultSetParameters = command.Parameters;
expressions.Add("_DataView_RowFilter_", "true");
AppendFilterExpressionsToWhere(sb, page, command, expressions, String.Empty);
string filter = sb.ToString();
if (filter.StartsWith("where"))
filter = filter.Substring(5);
filter = Regex.Replace(filter, (Regex.Escape(_parameterMarker) + "\\w+"), DoReplaceResultSetParameter);
resultView.RowFilter = filter;
if (page.PageSize > 0)
page.TotalRowCount = resultView.Count;
}
if (RequiresPreFetching(page))
page.ResetSkipCount(true);
return resultView.ToTable().CreateDataReader();
}
private SelectClauseDictionary ParseSelectExpressions(string selectClause)
{
SelectClauseDictionary expressions = new SelectClauseDictionary();
Match fieldMatch = SelectExpressionRegex.Match(selectClause);
while (fieldMatch.Success)
{
string expression = fieldMatch.Groups["Expression"].Value;
string fieldName = fieldMatch.Groups["FieldName"].Value;
string alias = fieldMatch.Groups["Alias"].Value;
if (!(String.IsNullOrEmpty(expression)))
{
if (String.IsNullOrEmpty(alias))
if (String.IsNullOrEmpty(fieldName))
alias = expression;
else
alias = fieldName;
if (!(expressions.ContainsKey(alias)))
expressions.Add(alias, expression);
}
fieldMatch = fieldMatch.NextMatch();
}
return expressions;
}
