--- title: "slint::DataTransfer Struct" --- ```cpp struct DataTransfer; ``` ```cpp #include ``` `DataTransfer` abstracts over the various ways of transferring data within an application and between applications. The details will depend on the current platform, but the common features are: - Each `DataTransfer` contains multiple views over the same data in different formats, specified by MIME type - The `DataTransfer` may contain an in-memory representation of the data, which can be sent and received within the current application - Serializing to a given format may be done eagerly or lazily ## Public Functions ### `DataTransfer` ```cpp slint::DataTransfer::DataTransfer() ``` Default constructor for `DataTransfer` ### `DataTransfer` ```cpp explicit slint::DataTransfer::DataTransfer(const SharedString &string) ``` Constructs a `DataTransfer` whose plain text representation is *string*. If *string* is empty, the resulting `DataTransfer` is empty (carries no plain text representation). ### `DataTransfer` ```cpp explicit slint::DataTransfer::DataTransfer(const Image &image) ``` Constructs a `DataTransfer` whose image representation is *image*. Conversion to the relevant format is done on-demand. If *image* is default-constructed, the resulting `DataTransfer` is empty (carries no image representation). ### `~DataTransfer` ```cpp slint::DataTransfer::~DataTransfer() ``` Destroys this `DataTransfer`, releasing any data it holds. ### `DataTransfer` ```cpp slint::DataTransfer::DataTransfer(const DataTransfer &other) ``` Creates a new `DataTransfer` that shares the data of *other*. ### `operator=` ```cpp DataTransfer & slint::DataTransfer::operator=(const DataTransfer &other) ``` Assigns *other* to this `DataTransfer` and returns a reference to this. ### `DataTransfer` ```cpp slint::DataTransfer::DataTransfer(DataTransfer &&other) noexcept ``` Move-constructs a `DataTransfer` from *other*, leaving *other* in a default-constructed state. ### `operator=` ```cpp DataTransfer & slint::DataTransfer::operator=(DataTransfer &&other) noexcept ``` Move-assigns *other* to this `DataTransfer` and returns a reference to this. ### `set_plain_text` ```cpp void slint::DataTransfer::set_plain_text(const SharedString &text) ``` Sets the plain text representation of this `DataTransfer`. Each `DataTransfer` can only have a single plain text representation; calling this again overwrites the previous one. Passing an empty `text` clears the previously-set plain text instead of storing it. ### `set_image` ```cpp void slint::DataTransfer::set_image(const Image &image) ``` Sets the image representation of this `DataTransfer`. Each `DataTransfer` can only have a single image representation; calling this again overwrites the previous one. Passing a default-constructed `Image` clears the previously-set image instead of storing it. ### `set_file_paths` ```cpp void slint::DataTransfer::set_file_paths(R &&paths) ``` Sets the list of local file paths transferred by this `DataTransfer`, overwriting any previously set list. An empty list clears the file paths. *paths* may be any range whose elements are convertible to `std::filesystem::path`, such as a `std::vector`. ### `has_plain_text` ```cpp bool slint::DataTransfer::has_plain_text() const ``` Returns `true` if this data transfer advertises a plain text representation. ### `has_image` ```cpp bool slint::DataTransfer::has_image() const ``` Returns `true` if this data transfer advertises an image representation. ### `has_file_paths` ```cpp bool slint::DataTransfer::has_file_paths() const ``` Returns `true` if this data transfer advertises a list of file paths. ### `is_empty` ```cpp bool slint::DataTransfer::is_empty() const ``` Returns `true` if this `DataTransfer` carries no data: no plain text, no image, no file paths, and no user data. ### `plain_text` ```cpp std::optional slint::DataTransfer::plain_text() const ``` Returns the plain text representation of this `DataTransfer`, or `std::nullopt` if no plain text representation is available. ### `image` ```cpp std::optional slint::DataTransfer::image() const ``` Returns the image representation of this `DataTransfer`, or `std::nullopt` if no image representation is available. ### `file_paths` ```cpp std::optional> slint::DataTransfer::file_paths() const ``` Returns the list of local file paths transferred by this `DataTransfer`, or `std::nullopt` if no file paths are available. ### `set_user_data` ```cpp void slint::DataTransfer::set_user_data(std::any value) ``` Overload of `set_user_data()` for callers that already hold a `std::any`. ### `user_data` ```cpp std::any slint::DataTransfer::user_data() const ``` Returns the user data, or an empty `std::any` if none is set. Use `std::any_cast` to extract the concrete value. ### `has_user_data` ```cpp bool slint::DataTransfer::has_user_data() const ``` Returns `true` if this `DataTransfer` holds user data. ### `clear_user_data` ```cpp void slint::DataTransfer::clear_user_data() ``` Clears the user data, if any. ## Friends ### `operator==` ```cpp bool operator==(const DataTransfer &a, const DataTransfer &b) ``` Compare two `DataTransfer` values for equality. This will return true if `b` is an unmodified clone of `a`, but if any modification has been done to either value since cloning then this will return false even if the two values are semantically identical.