C # WPF toolkit: come posso rendere modificabile una cella da un datagrid?

Question

Prendi nota del codice per questo piccolo programma C # WPF realizzato con Microsoft Visual Studio 2008:

XAML

<Window x:Class="WpfDatagridTest.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:WpfToolkit="http://schemas.microsoft.com/wpf/2008/toolkit"
    Title="Window1" Height="300" Width="300">
    <Grid>
        <WpfToolkit:DataGrid 
        x:Name="DataGrid_" ItemsSource="{Binding}"
        SelectionMode="Extended"
        CanUserAddRows="False" CanUserDeleteRows="False"
        CanUserResizeRows="False" CanUserSortColumns="False"
        AutoGenerateColumns="False"
        RowHeaderWidth="17" RowHeight="25" />
    </Grid>
</Window>

.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using Microsoft.Windows.Controls;

namespace WpfDatagridTest
{
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            const int MAX = 10;

            for(int i = 0; i < MAX; ++i)
                DataGrid_.Columns.Add(new DataGridTextColumn()
                {
                    Header = i
                });
            DataGrid_.Items.Add("");
        }
    }
}

---

Questo programma mostra semplicemente un datagrid del toolkit WPF con 10 colonne con intestazioni e una riga vuota.

Si verifica un problema quando si seleziona una determinata cella della riga vuota e si fa clic per modificarla: il programma si arresta in modo anomalo. In Visual Studio viene visualizzata una finestra di messaggio che dice: " Non esiste un codice sorgente disponibile per la posizione corrente. & Quot; Vorrei sapere come posso rendere modificabile una cella di un datagrid?

---

Ecco l'eccezione e stacktrace:

  

System.InvalidOperationException era   messaggio non gestito = " 'EditItem' non lo è   consentito per questa vista. "
  Source = " PresentationFramework "
  StackTrace:          at System.Windows.Controls.ItemCollection.System.ComponentModel.IEditableCollectionView.EditItem (Object   articolo)          at Microsoft.Windows.Controls.DataGrid.EditRowItem (Object   rowItem) in   C: \ dd \ WPF_1 \ src \ WPF \ src \ ControlsPack \ WPFToolkit \ DataGrid \ Microsoft \ Windows \ Controls \ DataGrid.cs: linea   3396          at Microsoft.Windows.Controls.DataGrid.OnExecutedBeginEdit (ExecutedRoutedEventArgs   e) in   C: \ dd \ WPF_1 \ src \ WPF \ src \ ControlsPack \ WPFToolkit \ DataGrid \ Microsoft \ Windows \ Controls \ DataGrid.cs: linea   2208          at Microsoft.Windows.Controls.DataGrid.OnExecutedBeginEdit (Object   mittente, ExecutedRoutedEventArgs e) in   C: \ dd \ WPF_1 \ src \ WPF \ src \ ControlsPack \ WPFToolkit \ DataGrid \ Microsoft \ Windows \ Controls \ DataGrid.cs: linea   2036          at System.Windows.Input.CommandBinding.OnExecuted (Object   mittente, ExecutedRoutedEventArgs e)          at System.Windows.Input.CommandManager.ExecuteCommandBinding (Object   mittente, ExecutedRoutedEventArgs e,   CommandBinding commandBinding)          at System.Windows.Input.CommandManager.FindCommandBinding (CommandBindingCollection   commandBindings, mittente oggetto,   RoutedEventArgs e, comando ICommand,   Esecuzione booleana)          at System.Windows.Input.CommandManager.FindCommandBinding (Object   mittente, RoutedEventArgs e, ICommand   comando, booleano eseguito)          at System.Windows.Input.CommandManager.OnExecuted (Object   mittente, ExecutedRoutedEventArgs e)          at System.Windows.UIElement.OnExecutedThunk (Object   mittente, ExecutedRoutedEventArgs e)          at System.Windows.Input.ExecutedRoutedEventArgs.InvokeEventHandler (Delegate   genericHandler, Target object)          at System.Windows.RoutedEventArgs.InvokeHandler (Delegato   gestore, oggetto target)          at System.Windows.RoutedEventHandlerInfo.InvokeHandler (Object   target, RoutedEventArgs   RoutedEventArgs)          at System.Windows.EventRoute.InvokeHandlersImpl (Object   source, args di RoutedEventArgs, booleano   rilanciato)          at System.Windows.UIElement.RaiseEventImpl (DependencyObject   mittente, RoutedEventArgs args)          at System.Windows.UIElement.RaiseEvent (RoutedEventArgs   args, fidato booleano)          at System.Windows.Input.RoutedCommand.ExecuteImpl (Object   parametro, IInputElement target,   Utente booleano Iniziato)          at System.Windows.Input.RoutedCommand.Execute (Object   parametro, IInputElement target)          presso Microsoft.Windows.Controls.DataGrid.BeginEdit (RoutedEventArgs   editingEventArgs) in   C: \ dd \ WPF_1 \ src \ WPF \ src \ ControlsPack \ WPFToolkit \ DataGrid \ Microsoft \ Windows \ Controls \ DataGrid.cs: linea   3059          at Microsoft.Windows.Controls.DataGridCell.OnAnyMouseLeftButtonDown (MouseButtonEventArgs   e) in   C: \ dd \ WPF_1 \ src \ WPF \ src \ ControlsPack \ WPFToolkit \ DataGrid \ Microsoft \ Windows \ Controls \ DataGridCell.cs: linea   748          at Microsoft.Windows.Controls.DataGridCell.OnAnyMouseLeftButtonDownThunk (Object   mittente, MouseButtonEventArgs e) in   C: \ dd \ WPF_1 \ src \ WPF \ src \ ControlsPack \ WPFToolkit \ DataGrid \ Microsoft \ Windows \ Controls \ DataGridCell.cs: line   726          at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler (Delegate   genericHandler, Object genericTarget)          at System.Windows.RoutedEventArgs.InvokeHandler (Delegato   gestore, oggetto target)          at System.Windows.RoutedEventHandlerInfo.InvokeHandler (Object   target, RoutedEventArgs   RoutedEventArgs)          at System.Windows.EventRoute.InvokeHandlersImpl (Object   source, args di RoutedEventArgs, booleano   rilanciato)          at System.Windows.UIElement.ReRaiseEventAs (DependencyObject   mittente, RoutedEventArgs args,   RoutedEvent newEvent)          at System.Windows.UIElement.CrackMouseButtonEventAndReRaiseEvent (DependencyObject   mittente, MouseButtonEventArgs e)          at System.Windows.UIElement.OnMouseDownThunk (Object   mittente, MouseButtonEventArgs e)          at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler (Delegate   genericHandler, Object genericTarget)          at System.Windows.RoutedEventArgs.InvokeHandler (Delegato   gestore, oggetto target)          at System.Windows.RoutedEventHandlerInfo.InvokeHandler (Object   target, RoutedEventArgs   RoutedEventArgs)          at System.Windows.EventRoute.InvokeHandlersImpl (Object   source, args di RoutedEventArgs, booleano   rilanciato)          at System.Windows.UIElement.RaiseEventImpl (DependencyObject   mittente, RoutedEventArgs args)          at System.Windows.UIElement.RaiseEvent (RoutedEventArgs   args, fidato booleano)          at System.Windows.Input.InputManager.ProcessStagingArea ()          at System.Windows.Input.InputManager.ProcessInput (InputEventArgs   ingresso)          at System.Windows.Input.InputProviderSite.ReportInput (InputReport   inputReport)          at System.Windows.Interop.HwndMouseInputProvider.ReportInput (IntPtr   hwnd, modalità InputMode, timestamp Int32,   RawMouseAzioni di azioni, Int32 x,   Int32 y, Int32 wheel)          at System.Windows.Interop.HwndMouseInputProvider.FilterMessage (IntPtr   hwnd, Int32 msg, IntPtr wParam, IntPtr   lParam, Boolean & amp; gestito)          at System.Windows.Interop.HwndSource.InputFilterMessage (IntPtr   hwnd, Int32 msg, IntPtr wParam, IntPtr   lParam, Boolean & amp; gestito)          at MS.Win32.HwndWrapper.WndProc (IntPtr   hwnd, Int32 msg, IntPtr wParam, IntPtr   lParam, Boolean & amp; gestito)          at MS.Win32.HwndSubclass.DispatcherCallbackOperation (Object   o)          at System.Windows.Threading.ExceptionWrapper.InternalRealCall (Delegate   callback, Object args, Boolean   isSingleParameter)          at System.Windows.Threading.ExceptionWrapper.TryCatchWhen (Object   sorgente, callback delegato, oggetto   args, Boolean isSingleParameter,   Delegate catchHandler)          at System.Windows.Threading.Dispatcher.WrappedInvoke (Delegate   callback, Object args, Boolean   isSingleParameter, Delegate   catchHandler)          at System.Windows.Threading.Dispatcher.InvokeImpl (DispatcherPriority   priorità, timeout del TimeSpan, delegato   metodo, Object args, booleano   isSingleParameter)          su System.Windows.Threading.Dispatcher.Invoke (DispatcherPriority   priorità, metodo delegato, oggetto arg)          at MS.Win32.HwndSubclass.SubclassWndProc (IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr   lParam)          at MS.Win32.UnsafeNativeMethods.DispatchMessage (MSG & amp;   msg)          at System.Windows.Threading.Dispatcher.PushFrameImpl (DispatcherFrame   telaio)          at System.Windows.Threading.Dispatcher.PushFrame (DispatcherFrame   telaio)          at System.Windows.Threading.Dispatcher.Run ()          at System.Windows.Application.RunDispatcher (Object   ignorare)          at System.Windows.Application.RunInternal (Window   finestra)          at System.Windows.Application.Run (Window   finestra)          at System.Windows.Application.Run ()          presso WpfDatagridTest.App.Main () in   C: \ Users \ Frank \ Documenti \ Visual_Studio_2008 \ Projects \ WpfDatagridTest \ WpfDatagridTest \ obj \ Debug \ App.g.cs: linea   0          a S

Answer 1

Stai impostando ItemsSource su Binding , ma non c'è DataContext, quindi questa associazione è inutile. Quindi stai generando le colonne nel code-behind e le riempi con dati temporanei. Da quanto ho capito su DataGrid, la modifica è supportata solo se ci sono dati a cui è legata la griglia. Altrimenti, quali dati stai modificando?

Inoltre, credo che esista una proprietà IsReadOnly (controlla la documentazione di DataGrid), che deve essere impostata su false (ma penso che sia falsa per impostazione predefinita).