在数据网格中添加上下文菜单，如何获取选择项值

Question

I am new in WPF programming with MVVM pattern. Now I have added the context menu in the datagrid. But, when I click the right mouse button, I don't know how to get the select row value. this is my xmal

 <DataGrid  AutoGenerateColumns="False" Grid.Row="1" CanUserAddRows="False" CanUserDeleteRows="False"
              ItemsSource="{Binding StoryList}">
        <DataGrid.Columns>
        <DataGridTextColumn Header="ID" Binding="{Binding ID}" Width="40" IsReadOnly="True" />
        <DataGridTextColumn Header="Title" Binding="{Binding Title}" Width="60" IsReadOnly="True"/>
        <DataGridTextColumn Header="StoryPoints" Binding="{Binding StoryPoints}" Width="90" IsReadOnly="True">
                <DataGridTextColumn.CellStyle>
                    <Style TargetType="DataGridCell">
                        <Style.Triggers>
                            <DataTrigger Binding="{Binding StoryPoints}" Value="0">
                                <Setter Property="Background" Value="Red"/>
                                <Setter Property="ToolTip" Value="Story Point cannot be 0."/>
                            </DataTrigger>                                
                        </Style.Triggers>
                    </Style>
                </DataGridTextColumn.CellStyle>
            </DataGridTextColumn>
            <DataGridTextColumn Header="Stack Rank" Binding="{Binding StackRank}" Width="80"/>
            <DataGridTextColumn Header="Estimate" Binding="{Binding Estimate}" Width="60"/>
            <DataGridTextColumn Header="CompletedWork" Binding="{Binding CompletedWork}" Width="120" />
            <DataGridTextColumn Header="RemainWork" Binding="{Binding RemainWork}" Width="110" />
            <DataGridTextColumn Header="CompleteProcess" Binding="{Binding CompletedProcess}" Width="110" />
            <DataGridTextColumn Header="YesterdayComments" Binding="{Binding YesterdayComments}" Width="120" />
            <DataGridTextColumn Header="TodayComments" Binding="{Binding TodayComments}" Width="120" />
        </DataGrid.Columns>
        <DataGrid.ContextMenu>
            <ContextMenu Name="StoryMenu" StaysOpen="True">
                <MenuItem Header="Add an Issue" Command="{Binding AddIssueCommand}" />
                <MenuItem Header="Burn Down Chart" Command="{Binding BurnDownChartCommand}"/>
            </ContextMenu>
        </DataGrid.ContextMenu>
    </DataGrid>

And here is my viewModel

 class MainViewModel:NotificationObject
{
    private ObservableCollection<Story> storyList;

    public ObservableCollection<Story> StoryList
    {
        get { return storyList; }
        set
        {
            storyList = value;
            this.RaisePropertyChanged("StoryList");
        }
    }
    public DelegateCommand AddIssueCommand { get; set; }
    public DelegateCommand BurnDownChartCommand { get; set; }
    private Story selectStory;

    public Story SelectStory
    {
        get { return selectStory; }
        set
        {
            selectStory = value;
            this.RaisePropertyChanged("SelectStory");
        }
    }

    public void LoadStory()
    {
        this.storyList = new ObservableCollection<Story>();
        Story story1 = new Story(){ID=1, Title="win App", StoryPoints=0, StackRank=1, Estimate=40, CompletedWork=10, RemainWork=30, CompletedProcess=25, TodayComments="Coding", YesterdayComments="N/a"};
        Story story2 = new Story() { ID = 2, Title = "win App", StoryPoints = 10, Estimate = 40, CompletedWork = 10, RemainWork = 30, CompletedProcess = 25, TodayComments = "Coding 20%", YesterdayComments = "N/a" };
        Story story3 = new Story() { ID = 3, Title = "win App", StoryPoints = 10, Estimate = 50, CompletedWork = 20, RemainWork = 30, CompletedProcess = 20, TodayComments = "Coding  30%", YesterdayComments = "N/a" };
        Story story4 = new Story() { ID = 4, Title = "win App", StoryPoints = 10, Estimate = 60, CompletedWork = 30, RemainWork = 30, CompletedProcess = 50, TodayComments = "Coding  40%", YesterdayComments = "N/a" };
        Story story5 = new Story() { ID = 5, Title = "win App", StoryPoints = 10, Estimate = 40, CompletedWork = 10, RemainWork = 30, CompletedProcess = 25, TodayComments = "Coding  50%", YesterdayComments = "N/a" };
        Story story6 = new Story() { ID = 6, Title = "win App", StoryPoints = 10, Estimate = 30, CompletedWork = 30, RemainWork = 0, CompletedProcess = 100, TodayComments = "Coding  60%", YesterdayComments = "N/a" };

        storyList.Add(story1);
        storyList.Add(story3);
        storyList.Add(story2);
        storyList.Add(story4);
        storyList.Add(story5);
        storyList.Add(story6);
    }
    public MainViewModel()
    {
        this.SelectStory = new Story();
        this.LoadStory();
        this.AddIssueCommand = new DelegateCommand(new Action(this.AddIssueCommandExecute));
    }

    public void AddIssueCommandExecute()
    {

        if (SelectStory != null)
        {
            System.Windows.MessageBox.Show("Add an Issue" + SelectStory.Title + "!");
        }
        else
        {
            System.Windows.MessageBox.Show("choose an story first!");
        }
        //System.Windows.MessageBox.Show("record" + RecordIndex);
    }
}![What I need][1]

Thank you very much

Answer 1

Expanding on Bolu's comment you could use SelectedItem to get the current item. Below is a quick example:

<DataGrid ItemsSource="{Binding Source}" SelectedItem="{Binding SelectedItemProperty, Mode=TwoWay}">
    <DataGrid.ContextMenu>
        <ContextMenu>
            <MenuItem Command="{Binding MyCommand}" Header="MyCommand"/>
        </ContextMenu>
    </DataGrid.ContextMenu>
    <DataGrid.Columns>
        <DataGridTextColumn Header="Name" Binding="{Binding Key, Mode=TwoWay}" Width="1*"/>
        <DataGridTextColumn Header="Value" Binding="{Binding Value, Mode=TwoWay}" Width="3*"/>
    </DataGrid.Columns>
</DataGrid>

SelectedItem is now bound to SelectedItemProperty in the ViewModel.

Answer 2

This is a common problem in WPF. The solution is to utilise a Tag property in the item DataTemplate to hold the data item. First, let's add this part:

<DataTemplate DataType="{x:Type YourDataTypeXmlNamespace:YourDataType}">
    <Border Tag="{Binding DataContext, RelativeSource={RelativeSource AncestorType={
x:Type YourViewsXmlNamespace:YourViewWhereThisIsDeclared}}}">
        ...
    </Border>
</DataTemplate>

Now that we have access to the DataContext of the UserControl which can be found in the Tag property of each data object, let's bind to this from the ContextMenu ... we do it using a handy property called PlacementTarget :

<ContextMenu DataContext="{Binding PlacementTarget.Tag, RelativeSource={
RelativeSource Self}}">
    <MenuItem Header="Do Something" Command="{Binding YourCommandInYourViewModel}" 
CommandParameter="{Binding YourCollection.CurrentItem}">
        ...
    </MenuItem>
</ContextMenu>

One thing to note is the YourCollection.CurrentItem property shown in the CommandParameter above. The CurrentItem property is a property that I added into my collection classes to bind to the SelectedItem properties of collection controls in the UI. If you don't have one of these, it's ok, but you will need a property that is bound to the SelectedItem property of your collection control for this to work. For my example, I have this:

<ListBox ItemsSource="{Binding YourCollection}" SelectedItem="{Binding 
YourCollection.CurrentItem}" />

Answer 3

bigworld12 has close to the right answer here, but it breaks if your context menu is templated. Try:

DataGridRow row =
            ((sender as MenuItem)?.GetAncestors()
               ?.FirstOrDefault(dpo => dpo.GetType() == typeof(ContextMenu)) as ContextMenu)
               ?.PlacementTarget as DataGridRow;

for the code-behind. I used nullable operators in case you somehow get here without the expected parent tree and target (maybe by triggering the context menu while off the grid.)

Answer 4

I know this is an old question, but i wanted to share this very easy solution.

XAML:

<ContextMenu x:Key="MyRowMenu1" DataContext="{Binding PlacementTarget, RelativeSource={RelativeSource Self}}">
     <MenuItem Click="MenuItem_Click" Header="Add to Favourites"/>
     <MenuItem Header="Copy" >
     <MenuItem Header="Copy Name"/>
     <MenuItem Header="Copy ID" />
     <MenuItem Header="Copy IP Adddress"/>
    </MenuItem>
</ContextMenu>

Code behind:

Private Sub MenuItem_Click(sender As Object, e As RoutedEventArgs)
    Dim row As DataGridRow = DirectCast(DirectCast(DirectCast(sender, MenuItem).GetParentObject, ContextMenu).PlacementTarget, DataGridRow)
    'replace with what ever item you want
    Dim srvr As Server = DirectCast(row.Item, Server)

End Sub

Answer 5

I think this is a similar case. I fixed it that way:

<ContextMenu x:Key="rowContextMenu" Background="Transparent" >
<MenuItem Header="{StaticResource LowPriority}" Style="{StaticResource menuStyle}"  
CommandParameter="1" Click="ChangePriority"/>
</ContextMenu>

C# Code:

    private async void ChangePriority(object sender, RoutedEventArgs a)
    {
        MyTypeInRow row = (MyTypeInRow)(((MenuItem)sender).DataContext);
     ...
    }

   DataGrid.ItemsSource contains ObservableCollection<MyTypeInRow>.