Question

ValueErrorTraceback (most recent call last) <ipython-input-33-eb3d96398060> in <module>()
     19     return arraynd.tolist();
     20 
---> 21 X_valid = normalizeImages(X_valid)
     22 #X_train = normalizeImages(X_train)
     23 #X_test = normalizeImages(X_test)

<ipython-input-33-eb3d96398060> in normalizeImages(data)
     16     for x in range(0, len(dflat)):
     17         dflat[x] = (dflat[x] - mindflat)/(maxdflat - mindflat)* 255
---> 18     arraynd = np.reshape(dflat, (x, y, z, w))
     19     return arraynd.tolist();
     20 

C:\ProgramData\Miniconda3\envs\carnd-term1\lib\site-packages\numpy\core\fromnumeric.py in reshape(a, newshape, order)
    222     except AttributeError:
    223         return _wrapit(a, 'reshape', newshape, order=order)
--> 224     return reshape(newshape, order=order)
    225 
    226 

ValueError: total size of new array must be unchanged

我的视图模型中的<ScrollViewer VerticalScrollBarVisibility="Auto"> <ListBox x:Name="RootListView" ItemsSource="{Binding Ratings}"> <ListBox.ItemTemplate> <DataTemplate> <Grid ShowGridLines="True"> <Grid.RowDefinitions> <RowDefinition Height="auto" /> <RowDefinition Height="auto" /> <RowDefinition Height="Auto" /> <RowDefinition Height="Auto" /> <RowDefinition Height="40" /> </Grid.RowDefinitions> <Grid.ColumnDefinitions> <ColumnDefinition /> <ColumnDefinition /> </Grid.ColumnDefinitions> .... Some TextBoxes with Labels are here to fill the grid ..... <Button Grid.Row="4" Grid.Column="1" Content="Delete" Command="{Binding ElementName=RootListView, Path=DataContext.DeleteRatingCommand}" CommandParameter="{Binding ElementName=RootListView, Path=SelectedItem}"> </Button> </Grid> </DataTemplate> </ListBox.ItemTemplate> </ListBox> </ScrollViewer>位于：

Ratings

public ObservableCollection<RatingModel> Ratings;是DeleteRatingCommand对象。

此视图中显示了一整套评级（包含信息的网格），每个都有一个删除按钮。当按下相应评级的按钮时，我想将评级对象发送到具有ICommand属性的视图模型。虽然调用了绑定方法，但是没有通过SelectedItem参数传递任何内容，特别是SelectedItem值。在这种情况下，如何正确使用null向视图模型发送有关要删除哪个评级的信息？还有其他可能性吗？我不确定这种方法是否正确。

Answer 1

我假设点击按钮并没有实际设置SelectedItem属性。

尝试将绑定更改为行上下文数据。

CommandParameter="{Binding Path=.}"

作为命令参数传递的WPF SelectedItem不返回值

1 个答案: