/// <summary>
/// Creates the Attributes Table if it does not already exist.
/// </summary>
private void InitAttributeTable()
{
// The Attributes either don't exist or have been loaded and will now replace the ones in the file.
if (Attributes == null || Attributes.Table?.Columns.Count > 0)
{
return;
}
// Only add an FID field if there are no attributes at all.
IDataTable newTable = new DS_DataTable();
newTable.Columns.Add("FID");
// Added by [email protected] - Index mode has no attributes and no features - so Features.count is Null and so was not adding any rows and failing
int numRows = IndexMode ? ShapeIndices.Count : Features.Count;
for (int i = 0; i < numRows; i++)
{
IDataRow dr = newTable.NewRow();
dr["FID"] = i;
newTable.Rows.Add(dr);
}
Attributes.Table = newTable;
}
/// <summary>
/// Reads just the content requested in order to satisfy the paging ability of VirtualMode for the DataGridView
/// </summary>
/// <param name="startIndex">The integer lower page boundary</param>
/// <param name="numRows">The integer number of attribute rows to return for the page</param>
/// <param name="fieldNames">The list or array of fieldnames to return.</param>
/// <returns>A DataTable populated with data rows with only the specified values.</returns>
public override IDataTable GetAttributes(int startIndex, int numRows, IEnumerable <string> fieldNames)
{
if (AttributesPopulated)
{
return(base.GetAttributes(startIndex, numRows, fieldNames));
}
IDataTable result = new DS_DataTable();
DataColumn[] columns = GetColumns();
// Always add FID in this paging scenario.
result.Columns.Add("FID", typeof(int));
var fields = fieldNames as IList <string> ?? fieldNames.ToList();
foreach (string name in fields)
{
foreach (var col in columns)
{
if (string.Equals(col.ColumnName, name, StringComparison.CurrentCultureIgnoreCase))
{
result.Columns.Add(col);
break;
}
}
}
for (int i = 0; i < numRows; i++)
{
IDataRow dr = result.NewRow();
dr["FID"] = startIndex + i;
result.Rows.Add(dr);
}
// Most use cases with an expression use only one or two fieldnames. Tailor for better
// performance in that case, at the cost of performance in the "read all " case.
// The other overload without fieldnames specified is designed for that case.
foreach (string field in fields)
{
if (field == "FID")
{
continue;
}
object[] values = _attributeTable.SupplyPageOfData(startIndex, numRows, field);
for (int i = 0; i < numRows; i++)
{
result.Rows[i][field] = values[i];
}
}
return(result);
}