How to select the role of a QSortFilterProxyModel from QML?

Saviz

I have a subclass of QSortFilterProxyModel to enable my ComboBox to filter records. Below is the code I currently have:

filter.hpp:

#ifndef FILTER_H
#define FILTER_H

#include <QObject>
#include <QSortFilterProxyModel>

class CustomProxyModel : public QSortFilterProxyModel
{
    Q_OBJECT
    Q_PROPERTY(QString filterText READ filterText WRITE setFilterText NOTIFY filterTextChanged)

public:
    explicit CustomProxyModel(QObject *parent = nullptr);

private:
    QString m_filterText = "";

signals:
    void filterTextChanged();

protected:
    bool filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const override;

public:
    QString filterText() const;
    void setFilterText(const QString &text);
};

#endif // FILTER_H

filter.cpp:

QString CustomProxyModel::filterText() const
{
    return m_filterText;
}

void CustomProxyModel::setFilterText(const QString &text)
{
    if (m_filterText != text) {
        m_filterText = text;
        emit filterTextChanged();
        invalidateFilter(); // Reapply the filter
    }
}

bool CustomProxyModel::filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const
{
    if (m_filterText.isEmpty()) {
        return true; // Accept all rows if no filter text is set
    }

    QModelIndex index = sourceModel()->index(sourceRow, 0, sourceParent);
    QVariant data = sourceModel()->data(index);

    qDebug() << "Data for filtering:" << data << "Type:" << data.typeName();

    return data.toString().contains(m_filterText, Qt::CaseInsensitive);
}

Additionally, here is the QML code I am using:

ApplicationWindow {
  width: 300
  height: 500
  
  ListModel {
    id: myListModel
    // My elements have multiple roles:
    ListElement { id: 1; name: "Alice" }
    ListElement { id: 2; name: "Bob" }
    ListElement { id: 3; name: "Charlie" }
  }

  // Registered C++ type:
  CustomProxyModel {
    id: proxyModel
    sourceModel: myListModel
    // How to set role?
    filterString: "Alice"
  }

  ComboBox {
    anchors.fill: parent
    model: proxyModel
    textRole: "name"
  }
}

The problem I’m facing is that I cannot figure out how to set the textRole that the QSortFilterProxyModel should use for filtering. Currently, it filters based on the first role, which is id (a number). However, I want it to filter based on the name role (a string). How can I achieve this?

dheerendra

Try something like this. Use the data method of index.

bool CustomProxyModel::filterAcceptsRow(int source_row, const QModelIndex &source_parent) const
{
const QModelIndex sourceIndex = sourceModel()->index(source_row, 0, source_parent);
// Some how get the the role you require.
const QString filterElement = sourceIndex.data(role).toString();
return(filterElement.toLower().startsWith(m_filterText));
}