.net - 如何引用附加属性作为数据绑定(bind)的来源？

Question

这是我的代码的一个大大简化的示例。

<Grid>

<Polygon
  Name="ply" Grid.Column="2" Grid.Row="0" Grid.RowSpan="3"
  Fill="Orange" Stroke="Orange" Points="0,1 1,3 2,2 2,0 0,0"
/>

<Line
  Grid.Column=    "{Binding ElementName=ply, Path=Grid.Column, Mode=OneWay}"
  Grid.Row=       "{Binding ElementName=ply, Path=Grid.Row, Mode=OneWay}"
  Grid.ColumnSpan="{Binding ElementName=ply, Path=Grid.ColumnSpan, Mode=OneWay}"
  Grid.RowSpan=   "{Binding ElementName=ply, Path=Grid.RowSpan, Mode=OneWay}"
  X1="0" Y1="0" X2="1" Y2="1"
/>

</Grid>

代码编译得很好，没有任何错误或警告 - 但是当我运行应用程序时，它会出现在输出窗口中:

System.Windows.Data Error: 39 : BindingExpression path error:
'Grid' property not found on 'object' ''Polygon' (Name='ply')'.
BindingExpression:Path=Grid.Column; DataItem='Polygon' (Name='ply');
target element is 'Line' (Name=''); target property is 'Column' (type 'Int32')

System.Windows.Data Error: 39 : BindingExpression path error:
'Grid' property not found on 'object' ''Polygon' (Name='ply')'.
BindingExpression:Path=Grid.Row; DataItem='Polygon' (Name='ply');
target element is 'Line' (Name=''); target property is 'Row' (type 'Int32')

System.Windows.Data Error: 39 : BindingExpression path error:
'Grid' property not found on 'object' ''Polygon' (Name='ply')'.
BindingExpression:Path=Grid.ColumnSpan; DataItem='Polygon' (Name='ply');
target element is 'Line' (Name=''); target property is 'ColumnSpan' (type 'Int32')

System.Windows.Data Error: 39 : BindingExpression path error:
'Grid' property not found on 'object' ''Polygon' (Name='ply')'.
BindingExpression:Path=Grid.RowSpan; DataItem='Polygon' (Name='ply');
target element is 'Line' (Name=''); target property is 'RowSpan' (type 'Int32')

我显然没有正确执行此操作，所以我的问题是:
如何在我的数据绑定(bind)中正确引用源元素上的附加属性“Grid.Whatever”？我是否必须改为在代码隐藏中执行绑定(bind)，还是使用不同语法的 XAML 绑定(bind)就足够了？

Answer 1

你会笑，但这只是语法略有不同。您只需要在附加的属性名称周围加上括号(这让我很长时间才弄清楚我第一次这样做的时候):

<Line
  Grid.Column=    "{Binding ElementName=ply, Path=(Grid.Column), Mode=OneWay}"
  Grid.Row=       "{Binding ElementName=ply, Path=(Grid.Row), Mode=OneWay}"
  Grid.ColumnSpan="{Binding ElementName=ply, Path=(Grid.ColumnSpan), Mode=OneWay}"
  Grid.RowSpan=   "{Binding ElementName=ply, Path=(Grid.RowSpan), Mode=OneWay}"
  X1="0" Y1="0" X2="1" Y2="1"
/>

希望这可以帮助，
安德森