PyQt5 QItemSelection class usage summary

QItemSelectionIt is a class used in the PyQt5 model/view framework to manage multiple project selection ranges, which are often used to handle the user's selected status in multiple selection operations (such as multiple selections for tables and lists). It stores multipleQItemSelectionRangeObjects to record complex selection areas and support selection across rows, columns, or any cell combination.

Core functions

• Multi-range selection: Supports storing multiple independent selection areas (such as non-sequentially selected rows or cells).
• ​Index operation: Merge, split or query selection ranges.
• Interact with the model:QItemSelectionModelCooperate to manage the selected status of the view component.

Common methods

Key Code Examples

1. Create and operate selection ranges

from  import QItemSelection, QItemSelectionRange, QModelIndex

# Assume that the model indexes index1 and index2 exist (such as cells in a table)index1 = QModelIndex()  # When using it, you need to obtain a valid index from the modelindex2 = QModelIndex()  # Example: (0, 0), (2, 2)
# Create a selection range (rectangular area from index1 to index2)range1 = QItemSelectionRange(index1, index2)

# Initialize QItemSelection and add rangeselection = QItemSelection()
(range1)

# Check whether the index is selectedprint("Include index1:", (index1))  # True

​2. Merge two selection areas

# Create another selection rangerange2 = QItemSelectionRange((3, 0), (3, 2))
selection2 = QItemSelection()
(range2)

# Merge into the first selection area(selection2)
print("Number of scopes after merge:", ())  # 2

​Use with QItemSelectionModel

QItemSelectionModelis the management view (such asQTableView) The core class of the state is selected. Pass signalselectionChangedCapable the user's selected action.

from  import QTableView, QApplication
from  import QItemSelectionModel

class MyTableView(QTableView):
    def __init__(self):
        super().__init__()
        # Initialize the model (assuming it is set)        (...)
        
        # Get the selected model and connect the signal        ().(self.handle_selection)

    def handle_selection(self, selected: QItemSelection, deselected: QItemSelection):
        # Handle new selected areas        for range in selected:
            top_left = ()
            bottom_right = ()
            print(f"Select the range: OK {top_left.row()}-{bottom_right.row()}, List {top_left.column()}-{bottom_right.column()}")

app = QApplication([])
window = MyTableView()
()
app.exec_()

Application scenarios

• ​Batch operation: The user selects multiple lines of data and performs deletion/export.
• Highlight: Dynamically change cell style according to the selected area.
• ​Data linkage: The data is synchronized between the master and slave views by selecting the status.

​Things to note

• Index validity:

  • When ensuring operationQModelIndexValid (if the model is not reset).

• Performance optimization:

  • Avoid frequent operations when processing large dataQItemSelection, you can merge and update the view.

• Signal and slot:

  • useselectionChangedWhen signaling, distinguishselected(Newly selected) anddeselected(Unselect) parameter.

ByQItemSelection, can efficiently manage complex user selection behaviors and provide flexible data interaction capabilities for model/view applications.

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