/// <summary>
/// Returns the getters for all columns.
/// </summary>
public static Delegate[] GetAllGetters(DataViewRowCursor cur)
{
var sch = cur.Schema;
var res = new List <Delegate>();
for (int i = 0; i < sch.Count; ++i)
{
if (sch[i].IsHidden)
{
continue;
}
var getter = GetColumnGetter(cur, SchemaHelper._dc(i, cur), sch);
if (getter == null)
{
throw Contracts.Except($"Unable to get getter for column {i} from schema\n{SchemaHelper.ToString(sch)}.");
}
res.Add(getter);
}
return(res.ToArray());
}
public static Delegate GetGetterChoice <T1, T2, T3>(DataViewRowCursor cur, DataViewSchema.Column col)
{
Delegate res = null;
try
{
res = cur.GetGetter <T1>(col);
if (res != null)
{
return(res);
}
}
catch (Exception)
{
}
try
{
res = cur.GetGetter <T2>(col);
if (res != null)
{
return(res);
}
}
catch (Exception)
{
}
try
{
res = cur.GetGetter <T3>(col);
if (res != null)
{
return(res);
}
}
catch (Exception)
{
}
if (res == null)
{
throw Contracts.ExceptNotImpl($"Unable to get a getter for column {col} of type {typeof(T1)} or {typeof(T2)} or {typeof(T3)} from schema\n{SchemaHelper.ToString(cur.Schema)}.");
}
return(res);
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="inputSchema">existing schema</param>
/// <param name="names">new columns</param>
/// <param name="types">corresponding types</param>
public TypeReplacementSchema(ISchema inputSchema, string[] names, DataViewType[] types)
{
_schemaInput = inputSchema;
if (names == null || names.Length == 0)
{
throw Contracts.ExceptEmpty("The extended schema must contain new names.");
}
if (types == null || types.Length != names.Length)
{
throw Contracts.Except("names and types must have the same length.");
}
_types = new Dictionary <int, DataViewType>();
_mappedColumns = new Dictionary <int, int>();
Contracts.Assert(types.Length == names.Length);
int index;
for (int i = 0; i < names.Length; ++i)
{
if (!inputSchema.TryGetColumnIndex(names[i], out index))
{
throw Contracts.Except("Unable to find column '{0}' in '{1}'", names[i], SchemaHelper.ToString(inputSchema));
}
_types[index] = types[i];
_mappedColumns[inputSchema.ColumnCount + i] = index;
}
}