使用QAbstractTableModel（Model/View）时如何将"Select one..."添加到QComboBox？

Question

我正在使用 QAbstractTableModel 填充 QComboBox。这很好用，但我希望始终有第一个组合框索引包含 "Select one...".

的值

这可能吗？如果可能 - 如何实现？

我有一个 combobox，我将其模型设置为：

model = ProjectTableModel(projects)
combobox.setModel(model)

我的模特：

class ProjectTableModel(QtCore.QAbstractTableModel):

    def __init__(self, projects=[], parent=None):
        QtCore.QAbstractTableModel.__init__(self, parent)
        self._projects = projects

    def rowCount(self, parent):
        return len(self._projects)

    def columnCount(self, parent):
        return 2

    def data(self, index, role):
        row = index.row()
        column = index.column()

        if role == QtCore.Qt.DisplayRole and column == 0:
            # Set the item's text
            project = self._projects[row]
            name = project.name()
            return name
        elif role == QtCore.Qt.UserRole and column == 0:
            # Set the "itemData"
            project = self._projects[row]
            id = project.id()
            return id

Answer 1

您可以在 getting/setting 值时添加适当的条件，并在必要时调整行 count/number。下面的示例显示了如何执行此操作，但您应该仔细检查所有代码，以确保在访问 _projects 项时始终正确调整该行。（请注意，在访问模型本身的行时，您不需要调整行号）。

class ProjectTableModel(QtCore.QAbstractTableModel):

    def __init__(self, projects=[], parent=None):
        QtCore.QAbstractTableModel.__init__(self, parent)
        self._projects = projects

    def rowCount(self, parent):
        return len(self._projects) + 1 # adjust row count

    def columnCount(self, parent):
        return 2

    def data(self, index, role):
        row = index.row() - 1 # adjust row number
        column = index.column()

        if role == QtCore.Qt.DisplayRole and column == 0:
            if row >= 0:
                # Set the item's text
                project = self._projects[row]
                return project.name()
            else:
                return 'Select one...'
        elif role == QtCore.Qt.UserRole and column == 0 and row >= 0:
            # Set the "itemData"
            project = self._projects[row]
            id = project.id()
            return id

    def setData(self, index, value, role):
        row = index.row() - 1  # adjust row number
        column = index.column()

        # ignore the first item in the model
        if role == QtCore.Qt.DisplayRole and column == 0 and row >= 0:
            project = self._projects[row]
            project.setName(value) # or whatever

使用QAbstractTableModel（Model/View）时如何将"Select one..."添加到QComboBox？

How to add "Select one..." to QComboBox when using QAbstractTableModel (Model/View)?

python

pyqt4

pyside

pyqt5

pyside2