QML中DelegateModel内Repeater的模型访问失败问题

尝试访问DelegateModel内部Repeater的模型时遇到异常：当Repeater中仅使用Text元素时，模型可正常访问，Text能正确获取modelData；但使用具备拖拽功能的自定义FruitTile元素时，Repeater模型无法访问，Tile内的Text无法读取模型数据。

用户代码示例：

FruitTile.qml #

import QtQuick 2.6 

Rectangle {
id: root
required property Item dragParent

signal pressed
signal released
signal clicked

property int visualIndex: 0


anchors {
   // horizontalCenter: parent.horizontalCenter
   // verticalCenter: parent.verticalCenter
}
radius: 3


MouseArea {
    id: mouseArea
    anchors.fill: parent
    drag.target: root
    onClicked: root.clicked()
    onPressed: root.pressed()
    onReleased: {
        parent.Drag.drop()
        root.released()
    }
}

 Drag.active: mouseArea.drag.active
 Drag.source: root
 Drag.hotSpot.x: root.width / 2
 Drag.hotSpot.y: root.height / 2

states: [
    State {
        when: mouseArea.drag.active
        ParentChange {
            target: root
            parent: root.dragParent
        }

        AnchorChanges {
            target: root
            anchors.horizontalCenter: undefined
            anchors.verticalCenter: undefined
        }
    }
]
}

DelegateTestModel.qml #

import QtQuick 2.7
import QtQuick.Controls 2.0
import QtQml.Models 2.2

Rectangle {
id:rootTest
width: 600; height: 100

GridView {
    anchors.fill: parent
    model: visualModel
}
DelegateModel {
    id: visualModel
    model: fruitDrinksModel
    delegate: DelegateDelegateModel { }    
}

ListModel {
    id: fruitDrinksModel

    ListElement {
        name: "Apple Cider"  
        color: "blue"
        modelIndex: 0  
    }
} 
}

DelegateDelegateModel.qml #

import QtQuick 2.7
import QtQuick.Controls 2.0
import QtQml.Models 2.2
import QtQuick.Layouts 1.15

ColumnLayout {
Text { text: "Fruit Drink Name: " + name}
Repeater {
    model:  fruitModel  

    FruitTile {
        anchors.top: modelyData.bottom
        dragParent: rootTest
        width: 100; height: 40
        border.width: 1
        color: "yellow"
        Text { text: "Fruit Name: " + modelData}
        //Text { text: "Name: " + model.named + "does not work"}
        //Text { text: "Name: " + named + "does not work"}

    }
  }
  ListModel{
      id: fruitModel
      ListElement { named: "Appley" }
      ListElement { named: "Orangie" }
      ListElement { named: "Bananananee" }
      ListElement { named: "Sure" }

  }

  }

自定义QML组件（FruitTile）存在作用域隔离，组件内部无法直接访问Repeater迭代产生的模型上下文（如modelData、model.named）。而Text作为Repeater的直接子项，能直接继承Repeater的模型作用域，所以可以正常读取数据。

通过给自定义组件添加属性，将Repeater的模型数据主动传递到组件内部，再在组件内使用这些属性展示数据，同时修正原代码中的拼写错误：

修改后的FruitTile.qml #

import QtQuick 2.6 

Rectangle {
    id: root
    required property Item dragParent
    // 添加接收模型数据的属性
    property string fruitName: ""

    signal pressed
    signal released
    signal clicked

    property int visualIndex: 0

    radius: 3

    MouseArea {
        id: mouseArea
        anchors.fill: parent
        drag.target: root
        onClicked: root.clicked()
        onPressed: root.pressed()
        onReleased: {
            parent.Drag.drop()
            root.released()
        }
    }

    Drag.active: mouseArea.drag.active
    Drag.source: root
    Drag.hotSpot.x: root.width / 2
    Drag.hotSpot.y: root.height / 2

    states: [
        State {
            when: mouseArea.drag.active
            ParentChange {
                target: root
                parent: root.dragParent
            }

            AnchorChanges {
                target: root
                anchors.horizontalCenter: undefined
                anchors.verticalCenter: undefined
            }
        }
    ]
}

修改后的DelegateDelegateModel.qml #

import QtQuick 2.7
import QtQuick.Controls 2.0
import QtQml.Models 2.2
import QtQuick.Layouts 1.15

ColumnLayout {
    Text { text: "Fruit Drink Name: " + name}
    Repeater {
        model:  fruitModel  

        FruitTile {
            // 修正原代码中的modelyData拼写错误
            anchors.top: parent.bottom
            dragParent: rootTest
            width: 100; height: 40
            border.width: 1
            color: "yellow"
            // 将模型数据绑定到组件属性
            fruitName: model.named
            // 使用组件内部属性读取数据
            Text { text: "Fruit Name: " + parent.fruitName}
        }
    }
    ListModel{
        id: fruitModel
        ListElement { named: "Appley" }
        ListElement { named: "Orangie" }
        ListElement { named: "Bananananee" }
        ListElement { named: "Sure" }
    }
}

内容的提问来源于stack exchange，提问作者David