protected virtual void OnReadDataSet(ReadDataSetEventArgs e)
{
if (ReadDataSet != null)
{
ReadDataSet(this, e);
}
}
/// <summary>
/// Create a DataList from a dataset
/// </summary>
/// <param name="logonId">Logon id</param>
/// <param name="queryName">Name given to the data set</param>
/// <param name="queryCriteria">The criteria used to create the dataset.
/// If there are mutiple critera parameters they should be concatenated into
/// one string.
/// This can be empty if the dataset will always be created by an identical query
/// or if the criteria has been added on to the end of the query name to
/// make the cache available for longer.</param>
/// <param name="collectionRequest">Information about the collection being requested</param>
/// <param name="mappings">Mappings to map each dataset field to the data list
/// entity property name</param>
/// <returns></returns>
public DataList <T> Create(Guid logonId, string queryName, string queryCriteria,
CollectionRequest collectionRequest,
ImportMapping[] mappings)
{
if (queryName == null || queryName.Trim() == string.Empty)
{
throw new Exception("QueryName must be specified");
}
if (collectionRequest == null)
{
throw new Exception("CollectionRequest must be specified");
}
if (collectionRequest.StartRow < 0)
{
throw new Exception("StartRow must be zero or greater");
}
DataSet dataSet = null;
DataSetsCache dataSetsCache = null;
if (Host.DataSetCachingOn)
{
// Get the datasets cache for the logged on user
dataSetsCache = Host.GetDataSetsCache(logonId);
//if we move from a higher page to page 1 then the start row will be 0
//we do not require to get a new dataset at this time
//if (collectionRequest.StartRow > 0 && !collectionRequest.ForceRefresh)
if (!collectionRequest.ForceRefresh)
{
// The start row is greater than zero and not forcing refresh
// so try to get a cached dataset.
dataSet = dataSetsCache.Retreive(queryName, queryCriteria);
}
}
if (dataSet == null)
{
// Create a new dataset
ReadDataSetEventArgs args = new ReadDataSetEventArgs();
// Call the event to read the dataset
OnReadDataSet(args);
dataSet = args.DataSet;
if (dataSet == null)
{
throw new Exception("No data set has been created");
}
if (Host.DataSetCachingOn)
{
// Add the dataset to the cache
dataSetsCache.Add(dataSet, queryName, queryCriteria);
}
}
// Assume there is only one table in the dataset.
// This may need to be enhanced later.
if (dataSet.Tables.Count != 1)
{
throw new Exception("Database query did not return 1 table");
}
DataTable table = dataSet.Tables[0];
DataList <T> dataList = new DataList <T>();
dataList.FirstRowNumber = collectionRequest.StartRow;
dataList.TotalRowCount = table.Rows.Count;
// Copy the rows from the dataset to the data list
ImportData(dataList, mappings, table,
collectionRequest.StartRow, collectionRequest.RowCount);
return(dataList);
}
