XAML “指定的视觉对象已经是另一个视觉对象的子对象或CompositionTarget的根对象”C# Wpf [duplicate]

izj3ouym  于 12个月前  发布在  C#
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这个问题已经有答案了：

Specified Visual is already a child of another Visual or the root of a CompositionTarget（1个答案）
14天前关闭
我有一个空白的多米诺骨牌，我想用这个函数用点填充它：

private void Arrange(Grid grid, byte dots)
        {

            Ellipse e = new Ellipse
            {
                Fill = new SolidColorBrush(Colors.Black)
            };

            Border b = new Border
            {
                Background = new SolidColorBrush(Colors.Black),
                Margin = new Thickness(0, 5, 0, 5),
                CornerRadius = new CornerRadius(2.5)
            };

            //BoneView.Layout.Children.Add(b);
            Grid.SetColumn(b, 1);

            if (dots == 0)
                return;

            if (dots == 1)
            {
                grid.Children.Add(e);
                Grid.SetColumn(e, 1);
                Grid.SetRow(e, 1);
                return;
            }

            if (dots == 2)
            {
                List<Ellipse> ellipses = new List<Ellipse>();
                for (int i = 0; i < dots; i++)
                {
                    ellipses.Add(e);
                    grid.Children.Add(ellipses[i]);
                }

                Grid.SetColumn(ellipses[1], 2);
                Grid.SetRow(ellipses[1], 2);
                return;
            }

            if (dots == 3)
            {
                List<Ellipse> ellipses = new List<Ellipse>();
                for (int i = 0; i < dots; i++)
                {
                    ellipses.Add(e);
                    grid.Children.Add(ellipses[i]);
                }

                Grid.SetColumn(ellipses[1], 2);
                Grid.SetRow(ellipses[1], 2);

                Grid.SetColumn(ellipses[2], 1);
                Grid.SetRow(ellipses[2], 1);
                return;
            }

            if (dots == 4)
            {
                List<Ellipse> ellipses = new List<Ellipse>();
                for (int i = 0; i < dots; i++)
                {
                    ellipses.Add(e);
                    grid.Children.Add(ellipses[i]);
                }

                Grid.SetColumn(ellipses[1], 2);
                Grid.SetRow(ellipses[1], 2);

                Grid.SetColumn(ellipses[2], 2);
                Grid.SetRow(ellipses[2], 0);

                Grid.SetColumn(ellipses[3], 0);
                Grid.SetRow(ellipses[3], 2);
                return;
            }

            if (dots == 5)
            {
                List<Ellipse> ellipses = new List<Ellipse>();
                for (int i = 0; i < dots; i++)
                {
                    ellipses.Add(e);
                    grid.Children.Add(ellipses[i]);
                }

                Grid.SetColumn(ellipses[1], 2);
                Grid.SetRow(ellipses[1], 2);

                Grid.SetColumn(ellipses[2], 2);
                Grid.SetRow(ellipses[2], 0);

                Grid.SetColumn(ellipses[3], 0);
                Grid.SetRow(ellipses[3], 2);

                Grid.SetColumn(ellipses[4], 1);
                Grid.SetRow(ellipses[4], 1);
                return;
            }

            if (dots == 6)
            {
                List<Ellipse> ellipses = new List<Ellipse>();
                for (int i = 0; i < dots; i++)
                {
                    ellipses.Add(e);
                    grid.Children.Add(ellipses[i]);
                }

                Grid.SetColumn(ellipses[1], 2);
                Grid.SetRow(ellipses[1], 2);

                Grid.SetColumn(ellipses[2], 2);
                Grid.SetRow(ellipses[2], 0);

                Grid.SetColumn(ellipses[3], 0);
                Grid.SetRow(ellipses[3], 2);

                Grid.SetColumn(ellipses[4], 1);
                Grid.SetRow(ellipses[4], 0);

                Grid.SetColumn(ellipses[5], 1);
                Grid.SetRow(ellipses[5], 2);
                return;
            }

在grid.Children.Add(e)处，它抛出“指定的视觉对象已经是另一个视觉对象的子对象或CompositionTarget的根对象”异常。
据我所知，这是因为椭圆e已经添加到网格中。
我该如何解决此问题？
下面是多米诺骨牌的设计：

<Border Background="AntiqueWhite"
            CornerRadius="7"
            >

        <Grid Name="Layout">
            <Grid.ColumnDefinitions>
                <ColumnDefinition/>
                <ColumnDefinition Width="5"/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>

            <Grid Grid.Column="0" x:Name="Left">
                <Grid.RowDefinitions>
                    <RowDefinition/>
                    <RowDefinition/>
                    <RowDefinition/>
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition/>
                    <ColumnDefinition/>
                    <ColumnDefinition/>
                </Grid.ColumnDefinitions>

            </Grid>

            <Grid Grid.Column="2" x:Name="Right">
                <Grid.RowDefinitions>
                    <RowDefinition/>
                    <RowDefinition/>
                    <RowDefinition/>
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition/>
                    <ColumnDefinition/>
                    <ColumnDefinition/>
                </Grid.ColumnDefinitions>

            </Grid>

        </Grid>

    </Border>
xaml

1条答案

按热度按时间
jucafojl

jucafojl1#

这是因为你在函数的顶部示例化了Ellipse，代码为Ellipse e = new Ellipse ...，然后当一个多米诺骨牌有多个点时，你为每个点添加相同的示例化e。每次要添加点时，都需要示例化Ellipse。
简单的解决方案是在添加点的for...each循环中示例化Ellipse，正如我在下面所做的那样。

private void Arrange(Grid grid, byte dots)
{
    // let's create a single brush for all the black dots
    // so we don't have to create a brush for each dot
    var blackBrush = new SolidColorBrush(Colors.Black);

    Border b = new Border
    {
        Background = new SolidColorBrush(Colors.Black),
        Margin = new Thickness(0, 5, 0, 5),
        CornerRadius = new CornerRadius(2.5)
    };

    //BoneView.Layout.Children.Add(b);
    Grid.SetColumn(b, 1);

    if (dots == 0)
        return;

    if (dots == 1)
    {
        // create ellipse to add
        Ellipse e = new Ellipse
        {
            Fill = blackBrush 
        };
        grid.Children.Add(e);
        Grid.SetColumn(e, 1);
        Grid.SetRow(e, 1);
        return;
    }

    if (dots == 2)
    {
        List<Ellipse> ellipses = new List<Ellipse>();
        for (int i = 0; i < dots; i++)
        {
            // create each ellipse to add
            Ellipse e = new Ellipse
            {
                Fill = blackBrush 
            };
            ellipses.Add(e);
            grid.Children.Add(ellipses[i]);
        }
        Grid.SetColumn(ellipses[1], 2);
        Grid.SetRow(ellipses[1], 2);
        return;
    }

    if (dots == 3)
    {
        List<Ellipse> ellipses = new List<Ellipse>();
        for (int i = 0; i < dots; i++)
        {
            // create each ellipse to add
            Ellipse e = new Ellipse
            {
                Fill = blackBrush 
            };
            ellipses.Add(e);
            grid.Children.Add(ellipses[i]);
        }
        Grid.SetColumn(ellipses[1], 2);
        Grid.SetRow(ellipses[1], 2);
        Grid.SetColumn(ellipses[2], 1);
        Grid.SetRow(ellipses[2], 1);
        return;
    }

    if (dots == 4)
    {
        List<Ellipse> ellipses = new List<Ellipse>();
        for (int i = 0; i < dots; i++)
        {
            // create each ellipse to add
            Ellipse e = new Ellipse
            {
                Fill = blackBrush 
            };
            ellipses.Add(e);
            grid.Children.Add(ellipses[i]);
        }
        Grid.SetColumn(ellipses[1], 2);
        Grid.SetRow(ellipses[1], 2);
        Grid.SetColumn(ellipses[2], 2);
        Grid.SetRow(ellipses[2], 0);
        Grid.SetColumn(ellipses[3], 0);
        Grid.SetRow(ellipses[3], 2);
        return;
    }

    if (dots == 5)
    {
        List<Ellipse> ellipses = new List<Ellipse>();
        for (int i = 0; i < dots; i++)
        {
            // create each ellipse to add
            Ellipse e = new Ellipse
            {
                Fill = blackBrush 
            };
            ellipses.Add(e);
            grid.Children.Add(ellipses[i]);
        }
        Grid.SetColumn(ellipses[1], 2);
        Grid.SetRow(ellipses[1], 2);
        Grid.SetColumn(ellipses[2], 2);
        Grid.SetRow(ellipses[2], 0);
        Grid.SetColumn(ellipses[3], 0);
        Grid.SetRow(ellipses[3], 2);
        Grid.SetColumn(ellipses[4], 1);
        Grid.SetRow(ellipses[4], 1);
        return;
    }

    if (dots == 6)
    {
        List<Ellipse> ellipses = new List<Ellipse>();
        for (int i = 0; i < dots; i++)
        {
            // create each ellipse to add
            Ellipse e = new Ellipse
            {
                Fill = blackBrush 
            };
            ellipses.Add(e);
            grid.Children.Add(ellipses[i]);
        }
        Grid.SetColumn(ellipses[1], 2);
        Grid.SetRow(ellipses[1], 2);
        Grid.SetColumn(ellipses[2], 2);
        Grid.SetRow(ellipses[2], 0);
        Grid.SetColumn(ellipses[3], 0);
        Grid.SetRow(ellipses[3], 2);
        Grid.SetColumn(ellipses[4], 1);
        Grid.SetRow(ellipses[4], 0);
        Grid.SetColumn(ellipses[5], 1);
        Grid.SetRow(ellipses[5], 2);
        return;
    }
}
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