- Qt 6.11
- Qt Core
- C++ Classes
- DataReference
- Qt 6.11.2 Reference Documentation

# QRangeModelAdapter::DataReference Struct

struct QRangeModelAdapter::DataReference

DataReference is a reference wrapper around an item in a QRangeModel. More...

This struct is under development and is subject to change.

This struct was introduced in Qt 6.11.

- List of all members, including inherited members

## Public Types

| const_value_type
| pointer
| value_type

## Public Functions

| DataReference(const QModelIndex &index)
| DataReference(const QRangeModelAdapter<Range, Protocol, Model>::DataReference &other)
| DataReference(QRangeModelAdapter<Range, Protocol, Model>::DataReference &&other)
QRangeModelAdapter<Range, Protocol, Model>::DataReference::const_value_type | get() const
bool | isValid() const
| operator QRangeModelAdapter<Range, Protocol, Model>::DataReference::const_value_type() const
QRangeModelAdapter<Range, Protocol, Model>::DataReference::pointer | operator->() const
QRangeModelAdapter<Range, Protocol, Model>::DataReference & | operator=(QRangeModelAdapter<Range, Protocol, Model>::DataReference &&other)
QRangeModelAdapter<Range, Protocol, Model>::DataReference & | operator=(QRangeModelAdapter<Range, Protocol, Model>::DataReference::value_type &&value)
QRangeModelAdapter<Range, Protocol, Model>::DataReference & | operator=(const QRangeModelAdapter<Range, Protocol, Model>::DataReference &other)
QRangeModelAdapter<Range, Protocol, Model>::DataReference & | operator=(const QRangeModelAdapter<Range, Protocol, Model>::DataReference::value_type &value)

## Detailed Description

Accessing an item in the model using the non-const overloads of at(), subscript operator[], or dereferencing a non-const iterator, returns a DataReference wrapper around the item in the model.

Assigning to that reference wrapper changes the data in the model using QAbstractItemModel API.

     adapter[0] = newValue;

A const version of the value itself can be accessed using get() or operator->().

     QRangeModelAdapter adapter(QList<Gadget>{ ~~~ });
     auto value = adapter[0]->value();
     // adapter[0]->setValue(); // not allowed - would not emit dataChanged()

In contrast to `std::reference_wrapper`, assigning one DataReference to another does not rebind the reference, but sets the value using copy- semantics.

     adapter[0] = adapter[1]; // items at row 0 and row 1 now have the same value

See also RowReference and ConstRowReference.

## Member Type Documentation

### `[alias]` DataReference::const_value_type

An alias for the const type of the items stored in the underlying range. If different columns in the model hold different types, then this is an alias to `const QVariant`.

### `[alias]` DataReference::pointer

An alias for the pointer type returned by operator->().

### `[alias]` DataReference::value_type

An alias for the type of the items stored in the underlying range. If different columns in the model hold different types, then this is an alias to QVariant.

## Member Function Documentation

### `[explicit noexcept]` DataReference::DataReference(const QModelIndex &index)

Constructs a DataReference wrapper for the item at index.

### DataReference::DataReference(const QRangeModelAdapter<Range, Protocol, Model>::DataReference &other)

Constructs a copy of other.

### DataReference::DataReference(QRangeModelAdapter<Range, Protocol, Model>::DataReference &&other)

Constructs a DataReference by moving from other.

### QRangeModelAdapter<Range, Protocol, Model>::DataReference::const_value_type DataReference::get() const

### DataReference::operator QRangeModelAdapter<Range, Protocol, Model>::DataReference::const_value_type() const

Returns the item value referred to by this DataReference as a const value.

### bool DataReference::isValid() const

Returns true if this DataReference refers to a valid model index.

### QRangeModelAdapter<Range, Protocol, Model>::DataReference::pointer DataReference::operator->() const

Returns a pointer to the value referred to by this DataReference.

### QRangeModelAdapter<Range, Protocol, Model>::DataReference &DataReference::operator=(QRangeModelAdapter<Range, Protocol, Model>::DataReference &&other)

Moves the value reference by other into the value referenced by this wrapper.

### QRangeModelAdapter<Range, Protocol, Model>::DataReference &DataReference::operator=(QRangeModelAdapter<Range, Protocol, Model>::DataReference::value_type &&value)

Move-assigns value to the underlying model item.

### QRangeModelAdapter<Range, Protocol, Model>::DataReference &DataReference::operator=(const QRangeModelAdapter<Range, Protocol, Model>::DataReference &other)

Assigns the item value referred to by other to the value referenced by this wrapper.

### QRangeModelAdapter<Range, Protocol, Model>::DataReference &DataReference::operator=(const QRangeModelAdapter<Range, Protocol, Model>::DataReference::value_type &value)

Assigns value to the underlying model item.