Qt Documentation

ChildRemoved events are sent to objects when children are added or removed. This property is ignored for non-editable comboboxes in styles that returns true for QStyle:: A convenience handler, childEvent , can be reimplemented to catch child events. Vor allem die weitere Modularisierung hat zur Folge, dass Qt 5. Mit der Vorstellung von Qt 5 wurde eine alternative Methode vorgestellt, die dies nun bereits zur Kompilierzeit vermag. Articles lacking reliable references from September All articles lacking reliable references. If the same sourceText is used in different roles within the same context, an additional identifying string may be passed in disambiguation 0 by default.

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The highlighted signal is emitted when the user highlights an item in the combobox popup list. All three signals exist in two versions, one with a QString argument and one with an int argument. If the user selects or highlights a pixmap, only the int signals are emitted. Whenever the text of an editable combobox is changed the editTextChanged signal is emitted. When the user enters a new string in an editable combobox, the widget may or may not insert it, and it can insert it in several locations.

It is possible to constrain the input to an editable combobox using QValidator ; see setValidator. By default, any input is accepted. A combobox can be populated using the insert functions, insertItem and insertItems for example. Items can be changed with setItemText. An item can be removed with removeItem and all items can be removed with clear. The text of the current item is returned by currentText , and the text of a numbered item is returned with text. The current item can be set with setCurrentIndex.

The number of items in the combobox is returned by count ; the maximum number of items can be set with setMaxCount. You can allow editing using setEditable. For editable comboboxes you can set auto-completion using setCompleter and whether or not the user can add duplicates is set with setDuplicatesEnabled.

You can access the model and view directly with model and view , but QComboBox also provides functions to set and get item data e. You can also set a new model and view with setModel and setView. For the text and icon in the combobox label, the data in the model that has the Qt:: Note that you cannot alter the SelectionMode of the view , e.

This enum specifies what the QComboBox should do when a new string is entered by the user. This enum specifies how the size hint of the QComboBox should adjust when new content is added or content changes. By default, for an empty combo box or a combo box in which no current item is set, this property contains an invalid QVariant.

By default, for an empty combo box or a combo box in which no current item is set, this property has a value of If the combo box is editable, the current text is the value displayed by the line edit. Otherwise, it is the value of the current item or an empty string if the combo box is empty or no current item is set. The setter setCurrentText simply calls setEditText if the combo box is editable.

Otherwise, if there is a matching text in the list, currentIndex is set to the corresponding index. See also editable and setEditText. By default, this property is false. The effect of editing depends on the insert policy. If enabled the default the combo box draws itself inside a frame, otherwise the combo box draws itself without any frame. Unless explicitly set this returns the default value of the current style.

This size is the maximum size that icons can have; icons of smaller size are not scaled up. This property holds the policy used to determine where user-inserted items should appear in the combobox. The default value is InsertAtBottom , indicating that new items will appear at the bottom of the list of items. If you set the maximum number to be less then the current amount of items in the combobox, the extra items will be truncated. This also applies if you have set an external model on the combobox.

By default, this property's value is derived from the highest signed integer available typically This property is ignored for non-editable comboboxes in styles that returns true for QStyle:: If this property is set to a positive value, the minimumSizeHint and sizeHint take it into account. If set prior to populating the combo box, the pop-up view will not be affected and will show the first column using this property's default value.

This property holds the policy describing how the size of the combobox changes when the content changes. Constructs a combobox with the given parent , using the default model QStandardItemModel. This signal is sent when the user chooses an item in the combobox. The item's index is passed. Note that this signal is sent even when the choice is not changed.

If you need to know when the choice actually changes, use signal currentIndexChanged. Signal activated is overloaded in this class. To connect to this signal by using the function pointer syntax, Qt provides a convenient helper for obtaining the function pointer as shown in this example:.

The item's text is passed. Adds an item to the combobox with the given text , and containing the specified userData stored in the Qt:: The item is appended to the list of existing items. Adds an item to the combobox with the given icon and text , and containing the specified userData stored in the Qt:: Adds each of the strings in the given texts to the combobox. Each item is appended to the list of existing items in turn.

If you have set an external model on the combobox this model will still be cleared when calling this function. See also setCompleter and editable. This signal is sent whenever the currentIndex in the combobox changes either through user interaction or programmatically.

The item's index is passed or -1 if the combobox becomes empty or the currentIndex was reset. Signal currentIndexChanged is overloaded in this class. Notifier signal for property currentIndex. This signal is sent whenever currentText changes. The new value is passed as text. Notifier signal for property currentText. September ist die Version 4. Die neue Hauptversion bringt u. Vor allem die weitere Modularisierung hat zur Folge, dass Qt 5. Bis mindestens Qt 6. Es gibt derzeit folgende Varianten des Qt Frameworks: Diese Unterteilung existiert heute nicht mehr.

Das Konzept kann als Anwendung des Beobachter-Entwurfsmusters angesehen werden. Anders als bei der Verwendung von Funktionszeigern bzw. Mit der Vorstellung von Qt 5 wurde eine alternative Methode vorgestellt, die dies nun bereits zur Kompilierzeit vermag.

Andernfalls wird QueuedConnection verwendet. Diese dynamische Entscheidung findet auch bei UniqueConnection statt, jedoch ist zu einem Signal lediglich ein Slot erlaubt. Qt verwendete bis zur neuesten Version eine eigene Zeichenengine sowie Steuerelemente. Weitere Makros werden in selbst geschriebenen Header-Dateien expandiert, um deren Funktionsdeklarationen bereitzustellen.

Daneben findet die Bibliothek aber auch in anderen Anwendungsgebieten breite Verwendung. Dies ist die gesichtete Version , die am 6. September markiert wurde.

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