Question

我尝试创建级联下拉列表，当我选择第一个时它工作正常。在SelectionChanged上我尝试将第二个下拉列表绑定在它后面的代码上显示结果罚款。但下拉显示为空。我的代码是......

 Location ld = new Location();
            ld = categoryList.SelectedItem as Location;
            string id = "0";
            try
            {
                id = Convert.ToString(ld.id);
            }
            catch (Exception ex)
            { }
            if (id != "0")
            {
              //  lstSublocation.Visibility = Visibility.Visible;
                var lst = _lstlocation.Where(z => z.id == id).Select(z => z.sub_location).ToList();
                lstSublocation.ItemsSource = lst;
            }

在lst中显示2项。

<toolkit:ListPicker x:Name="lstSublocation" Foreground="Black"   
                         BorderThickness="2" SelectionMode="Single"  
                        VerticalAlignment="Bottom" Margin="12,0,10,460" BorderBrush="LightGray"  Height="68" >
                    <toolkit:ListPicker.ItemTemplate>
                        <DataTemplate>
                            <StackPanel Orientation="Horizontal">
                                <TextBlock Text="{Binding name}" Margin="12 0 0 0" Foreground="Black"/>
                            </StackPanel>
                        </DataTemplate>
                    </toolkit:ListPicker.ItemTemplate>
                    <toolkit:ListPicker.FullModeItemTemplate>
                        <DataTemplate>
                            <StackPanel Orientation="Horizontal" Margin="0 21 0 20">
                                <TextBlock Text="{Binding name}"
                                       Foreground="Black"
                                       />
                            </StackPanel>
                        </DataTemplate>
                    </toolkit:ListPicker.FullModeItemTemplate>
                </toolkit:ListPicker>

这是前端代码..... :( 2小时与这个代码挣扎像wrestlemania战斗...... :)

Answer 1

代码应该有效（如已发布），这可能是问题所在

var lst = _lstlocation.Where(z => z.id == id).Select(z => z.sub_location).ToList();
lstSublocation.ItemsSource = lst;

在lstSublocation.ItemsSource = lst;处设置一个断点并检查lst是什么

确保它实际上是List<your_model>，并且your_model的属性name不仅仅是公共变量..就像这样

public class sample_model
{
    public sample_model()
    {
        this.name = "default";
    }

    public string name { get; set; }   // this is bindable
    // public string name;             // this is NOT bindable
}

wp8中的级联下拉列表

1 个答案: