Getting WPF Data Grid Context Menu Click Row

问题:

I have a WPF DataGrid

<DataGrid AutoGenerateColumns="False"  Name="dataGrid1"  IsReadOnly="True" >
<DataGrid.Columns>
    <DataGridTextColumn Header="Site" Binding="{Binding Site}" Width="150" />
    <DataGridTextColumn Header="Subject" Binding="{Binding Subject}" Width="310" />
</DataGrid.Columns>
<DataGrid.ContextMenu>
    <ContextMenu>
        <MenuItem Header="Delete" Click="Context_Delete">
            <MenuItem.Icon>
                <Image Width="12" Height="12" Source="Images/Delete.png" />
            </MenuItem.Icon>
        </MenuItem>
    </ContextMenu>
</DataGrid.ContextMenu>
</DataGrid>

I have the click event handler as:

private void Context_Delete(object sender, System.EventArgs e)  { }

How do I get the row on which the Context Menu was before the click? The sender object is System.Windows.Controls.MenuItem, not the DataGridRow. How do I get the DataGridRow where the Context Menu was clicked. (I set the DataGrid.ItemSource in the code behind file.)

回答1:

So based on your example code, I presume you bind your DataGrid to an ObservableCollection of objects of which you bind the properties Site and Subject to the DataGridColumns.

Essentially, all you need to do is figure out what the item bound to the clicked DataGridRow is and remove that from your ObservableCollection. Here is some example code to get you started:

private void Context_Delete(object sender, RoutedEventArgs e)
{
    //Get the clicked MenuItem
    var menuItem = (MenuItem)sender;

    //Get the ContextMenu to which the menuItem belongs
    var contextMenu = (ContextMenu)menuItem.Parent;

    //Find the placementTarget
    var item = (DataGrid)contextMenu.PlacementTarget;

    //Get the underlying item, that you cast to your object that is bound
    //to the DataGrid (and has subject and state as property)
    var toDeleteFromBindedList = (YourObject)item.SelectedCells[0].Item;

    //Remove the toDeleteFromBindedList object from your ObservableCollection
    yourObservableCollection.Remove(toDeleteFromBindedList);
}

回答2:

Typically, you do not deal with rows (if you do - think again about the reasons) - instead you work with view model. When you open context menu, you get your item selected, so it can be accessed via the DataGrid.SelectedItem property. However, if you really need DataGridRow - you have your DataGrid.SelectedIndex and there is a lot of answers here on SO on how to get the row. like Get row in datagrid

回答3:

To expand morincer's point above with an example, I ended up with a simpler approach...

 private void MenuItem_OnClickRemoveSource(object sender, RoutedEventArgs e)
 {
     if (SourceDataGrid.SelectedItem == null) return;  //safety first

     _importViewModel.SourceList.Remove((SourceFileInfo)SourceDataGrid.SelectedItem);
 }

In my case, the

_importViewModel.SourceList 

is the ObservableCollection the rows are bound to. So per best practices, I simple remove the selected item from the collection and the binding takes care of the UI.

回答4:

dsfgsho's answer worked for me, but right clicking on a grid row does not automatically select it. This means that if your focus is elsewhere and you right-click and select a context menu item, you can get an out of range exception on item.SelectedCells[0], or if you have a row selected and right-click on a different row, you may get unexpected results.

I dealt with this by handling "PreviewMouseRightButtonDown" on the Datagrid. Here I am explicitly selecting a row when it is right-clicked. I forget where my UIHelpers class came from (probably elsewhere on this site - I was using it to resolve drag & drop items), but this should point you in the right direction if you are running into this problem. This is an extension of the accepted answer:

// handle right mouse click to select the correct item for context menu usage
    private void myDataGrid_PreviewMouseRightButtonDown(object sender, MouseButtonEventArgs e)
    {
        //find the clicked row
        DataGridRow row = UIHelpers.TryFindFromPoint<DataGridRow>((UIElement) sender, e.GetPosition(myDataGrid));
        if (row == null)
        {
            Debug.WriteLine("Row is null");
            return;
        }
        else
        {
            Debug.WriteLine("Grid Row Index is " + row.GetIndex().ToString());
            (sender as DataGrid).SelectedIndex = row.GetIndex();
        }
    }

回答5:

Elemental Pete's UIHelper probably stemmed from:

http://www.hardcodet.net/2009/03/moving-data-grid-rows-using-drag-and-drop

This Article lists a Zip that contains UIHelper.cs. It's not my Code so no copy/paste here.