我的数据库中有一个名为Groups的表，如下所示：
Groups
|--GroupID
|--GroupName
|--ParentID
|--NatureOfGroupID
|--EffectID
这是上表的关系图：
我在一个有两列的窗口中有一个组合框。这是xaml：
<ComboBox ItemsSource="{Binding DataContext.GroupNamesWithCorrespondingEffects, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Page}}}"
SelectedValue="{Binding ParentID}" SelectedValuePath="GroupID">
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding GroupName}" Width="200" />
<TextBlock Text="{Binding CorrespondingEffect}" />
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
实际上，我想显示GroupName及其对应的效果，但是当用户选择任何项时，我希望将SelectedValue作为ParentID。
这是GroupNameWithCorrespondingEffect.cs的实现
public class GroupNameWithCorrespondingEffect : MainViewModel
{
private string _groupName;
public string GroupName
{
get
{
return _groupName;
}
set
{
_groupName = value;
OnPropertyChanged("GroupName");
}
}
private string _correspondingEffect;
public string CorrespondingEffect
{
get
{
return _correspondingEffect;
}
set
{
_correspondingEffect = value;
OnPropertyChanged("CorrespondingEffect");
}
}
}
这是groupsViewModel.cs的代码
public class GroupsViewModel : MainViewModel
{
public GroupsViewModel()
{
using (Entities db = new Entities())
{
GroupNamesWithCorrespondingEffects = (from g in db.Groups
select new GroupNameWithCorrespondingEffect
{
GroupName = g.GroupName,
CorrespondingEffect = g.Master_Effects.Effect
}).ToList();
NaturesOfGroup = (from m in db.Master_NatureOfGroup
select m).ToList();
}
SaveChangesCommand = new RelayCommand(SaveGroup);
CurrentGroup = new Group();
}
private Group _currentGroup;
public Group CurrentGroup
{
get
{
return _currentGroup;
}
set
{
_currentGroup = value;
OnPropertyChanged("CurrentGroup");
}
}
private List<GroupNameWithCorrespondingEffect> _groupNamesWithCorrespondingEffects;
public List<GroupNameWithCorrespondingEffect> GroupNamesWithCorrespondingEffects
{
get
{
return _groupNamesWithCorrespondingEffects;
}
set
{
_groupNamesWithCorrespondingEffects = value;
OnPropertyChanged("GroupNamesWithCorrespondingEffects");
}
}
private List<Master_NatureOfGroup> _naturesOfGroup;
public List<Master_NatureOfGroup> NaturesOfGroup
{
get
{
return _naturesOfGroup;
}
set
{
_naturesOfGroup = value;
OnPropertyChanged("NaturesOfGroup");
}
}
public ICommand SaveChangesCommand { get; set; }
private void SaveGroup(object obj)
{
Group cGroup = new Group()
{
GroupName = CurrentGroup.GroupName,
**ParentID = CurrentGroup.ParentID,**
NatureOfGroupID = CurrentGroup.NatureOfGroupID,
EffectID = CurrentGroup.EffectID
};
using (Entities db = new Entities())
{
db.Groups.Add(cGroup);
db.SaveChanges();
GroupNamesWithCorrespondingEffects = (from g in db.Groups
select new GroupNameWithCorrespondingEffect
{
GroupName = g.GroupName,
CorrespondingEffect = g.Master_Effects.Effect
}).ToList();
}
}
}
当我调试并在标有** .... **的行上放置断点时，我总是得到CurrentGroup.ParentID = null。
更新：
<Page.DataContext>
<vm:GroupsViewModel />
</Page.DataContext>
<Grid DataContext="{Binding CurrentGroup}">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="0.6*" />
<ColumnDefinition Width="0.6*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="1" Grid.Column="1" Text="Name" HorizontalAlignment="Left"/>
<TextBlock Grid.Row="1" Grid.Column="1" Text=" : " HorizontalAlignment="Right"/>
<TextBox Grid.Row="1" Grid.Column="2" Grid.ColumnSpan="2" Text="{Binding GroupName}"/>
<TextBlock Grid.Row="2" Grid.Column="1" Text="Under" HorizontalAlignment="Left"/>
<TextBlock Grid.Row="2" Grid.Column="1" Text=" : " HorizontalAlignment="Right"/>
<ComboBox x:Name="cbUnder" Grid.Row="2" Grid.Column="2" Grid.ColumnSpan="2"
ItemsSource="{Binding DataContext.GroupNamesWithCorrespondingEffects, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Page}}}"
SelectedValue="{Binding ParentID}" SelectedValuePath="GroupID">
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding GroupName}" Width="200" />
<TextBlock Text="{Binding CorrespondingEffect}" />
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
<TextBlock Grid.Row="3" Grid.Column="1" Text="Nature of Group" HorizontalAlignment="Left" Visibility="{Binding Visibility, ElementName=cbNature}"/>
<TextBlock Grid.Row="3" Grid.Column="1" Text=" : " HorizontalAlignment="Right" Visibility="{Binding Visibility, ElementName=cbNature}"/>
<ComboBox x:Name="cbNature" Grid.Row="3" Grid.Column="2" Visibility="{Binding SelectedIndex, Converter={StaticResource selectedIndexToVisibilityConverter}, ElementName=cbUnder}"
ItemsSource="{Binding DataContext.NaturesOfGroup, RelativeSource={RelativeSource AncestorType={x:Type Page}}}" DisplayMemberPath="Nature"
SelectedValue="{Binding NatureOfGroupID}" SelectedValuePath="NatureOfGroupID"/>
<StackPanel Grid.Row="5" Grid.Column="4" Orientation="Horizontal">
<Button Content="Save" Command="{Binding DataContext.SaveChangesCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Page}}}"/>
</StackPanel>
</Grid>
最佳答案
我可以在您的代码中看到两个问题。
首先你提到
实际上我想显示GroupName及其对应的效果，但是
当用户选择任何项目时，我想获取SelectedValue作为
ParentID。
但是在组合框声明中，您设置了SelectedValuePath="GroupID"。应将其设置为ParentID-SelectedValuePath="ParentID"。
其次，即使将SelectedValuePath设置为ParentID，它也不起作用，因为combobox ItemsSource是GroupNameWithCorrespondingEffect的列表，其中没有任何属性ParentID。
为了使SelectedValuePath工作，基础模型类应具有该属性，因此请创建一个属性，并像其他两个属性一样从数据库中填充它。
GroupNamesWithCorrespondingEffects = (from g in db.Groups
select new GroupNameWithCorrespondingEffect
{
GroupName = g.GroupName,
CorrespondingEffect = g.Master_Effects.Effect,
ParentID = g.ParentId
}).ToList();
因此，为了使您的解决方案起作用，您必须修复这两个问题。
关于c# - 多列组合框中的选定值，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/21860012/