Code to check if a cell of a DataGrid is currently

问题:

Is there a simple possibility to check if the DataGrid is currently in EditMode (Without to subscribe to BeginningEdit and CellEditEnding)

回答1:

It seems you can also get this information from the items view, namely this works:

IEditableCollectionView itemsView = stateGrid.Items;
if (itemsView.IsAddingNew || itemsView.IsEditingItem)
{
    stateGrid.CommitEdit(DataGridEditingUnit.Row, true);
}

I have not confirmed this but most likely you could get these flags in a viewmodel if your bound collection provides an IEditableCollectionView.

回答2:

Ok, I havent found a simple solution and no one pointed me to one. The following code can be used to add an attached property IsInEditMode to a DataGrid. Hope it helps someone:

public class DataGridIsInEditModeTracker {

    public static bool GetIsInEditMode(DataGrid dataGrid) {
        return (bool)dataGrid.GetValue(IsInEditModeProperty);
    }

    private static void SetIsInEditMode(DataGrid dataGrid, bool value) {
        dataGrid.SetValue(IsInEditModePropertyKey, value);
    }

    private static readonly DependencyPropertyKey IsInEditModePropertyKey = DependencyProperty.RegisterAttachedReadOnly("IsInEditMode", typeof(bool), typeof(DataGridIsInEditModeTracker), new UIPropertyMetadata(false));

    public static readonly DependencyProperty IsInEditModeProperty = IsInEditModePropertyKey.DependencyProperty;


    public static bool GetProcessIsInEditMode(DataGrid dataGrid) {
        return (bool)dataGrid.GetValue(ProcessIsInEditModeProperty);
    }

    public static void SetProcessIsInEditMode(DataGrid dataGrid, bool value) {
        dataGrid.SetValue(ProcessIsInEditModeProperty, value);
    }


    public static readonly DependencyProperty ProcessIsInEditModeProperty =
        DependencyProperty.RegisterAttached("ProcessIsInEditMode", typeof(bool), typeof(DataGridIsInEditModeTracker), new FrameworkPropertyMetadata(false, delegate(DependencyObject d,DependencyPropertyChangedEventArgs e) {

            DataGrid dataGrid = d as DataGrid;
            if (null == dataGrid) {
                throw new InvalidOperationException("ProcessIsInEditMode can only be used with instances of the DataGrid-class");
            }
            if ((bool)e.NewValue) {
                dataGrid.BeginningEdit += new EventHandler<DataGridBeginningEditEventArgs>(dataGrid_BeginningEdit);
                dataGrid.CellEditEnding += new EventHandler<DataGridCellEditEndingEventArgs>(dataGrid_CellEditEnding);
            } else {
                dataGrid.BeginningEdit -= new EventHandler<DataGridBeginningEditEventArgs>(dataGrid_BeginningEdit);
                dataGrid.CellEditEnding -= new EventHandler<DataGridCellEditEndingEventArgs>(dataGrid_CellEditEnding);
            }
        }));

    static void dataGrid_CellEditEnding(object sender, DataGridCellEditEndingEventArgs e) {            
        SetIsInEditMode((DataGrid)sender,false);
    }

    static void dataGrid_BeginningEdit(object sender, DataGridBeginningEditEventArgs e) {
        SetIsInEditMode((DataGrid)sender, true);
    }                  
}

To use it, set on the datagrid the ProcessIsInEditMode- property to true:

<DataGrid local:DataGridIsInEditModeTracker.ProcessIsInEditMode="True" ..  other properties ..>

Afer that you will have the IsInEditMode-property in sync with the mode of the DataGrid. If you want also the editing cell, change the code in BeginningEdit accoringly.

回答3:

I found a shorter workaround (VB.NET/C#):

VB.NET

<Extension>
Public Function GetContainerFromIndex(Of TContainer As DependencyObject) _
    (ByVal itemsControl As ItemsControl, ByVal index As Integer) As TContainer
  Return DirectCast(
    itemsControl.ItemContainerGenerator.ContainerFromIndex(index), TContainer)
End Function

<Extension>
Public Function IsEditing(ByVal dataGrid As DataGrid) As Boolean
  Return dataGrid.GetEditingRow IsNot Nothing
End Function

<Extension>
Public Function GetEditingRow(ByVal dataGrid As DataGrid) As DataGridRow
  Dim sIndex = dataGrid.SelectedIndex
  If sIndex >= 0 Then
    Dim selected = dataGrid.GetContainerFromIndex(Of DataGridRow)(sIndex)
    If selected.IsEditing Then Return selected
  End If

  For i = 0 To dataGrid.Items.Count - 1
    If i = sIndex Then Continue For
    Dim item = dataGrid.GetContainerFromIndex(Of DataGridRow)(i)
    If item.IsEditing Then Return item
  Next

  Return Nothing
End Function

C#:

public static TContainer GetContainerFromIndex<TContainer>
  (this ItemsControl itemsControl, int index)
    where TContainer : DependencyObject
{
  return (TContainer)
    itemsControl.ItemContainerGenerator.ContainerFromIndex(index);
}

public static bool IsEditing(this DataGrid dataGrid)
{
  return dataGrid.GetEditingRow() != null;
}

public static DataGridRow GetEditingRow(this DataGrid dataGrid)
{
  var sIndex = dataGrid.SelectedIndex;
  if (sIndex >= 0)
  {
    var selected = dataGrid.GetContainerFromIndex<DataGridRow>(sIndex);
    if (selected.IsEditing) return selected;
  }

  for (int i = 0; i < dataGrid.Items.Count; i++)
  {
    if (i == sIndex) continue;
    var item = dataGrid.GetContainerFromIndex<DataGridRow>(i);
    if (item.IsEditing) return item;
  }

  return null;
}

回答4:

All the answers above using IsEditing on the datagridrow or IsEdititngItem on the IEditableCollectionView are partial answers to me :

If the user enter edition, then clics on any other cell, the EndEdit event is fired but the DataGridRow has still the property IsEditing to True !!! And if you try to find the DataGridCell responsible, its IsEditingProperty Is always false... I think it's a bug. And to have the desired behaviour, I had to write this Ugly workaround

Public Shared ReadOnly ForceEndEditProp As DependencyProperty =
        DependencyProperty.RegisterAttached("ForceEndEdit", GetType(Boolean),
        GetType(DataGridEditing), New PropertyMetadata(False, AddressOf ForceEndEditChanged))

Protected Shared Sub ForceEndEditChanged(d As DependencyObject, e As DependencyPropertyChangedEventArgs)
    Dim g As DataGrid = TryCast(d, DataGrid)
    If g Is Nothing Then Return
    ''IsCommiting prevents a StackOverflow ...
    Dim IsCommiting As Boolean = False
    AddHandler g.CellEditEnding, Sub(s, e1)
                                     If IsCommiting Then Return
                                     IsCommiting = True
                                     g.CommitEdit(DataGridEditingUnit.Row, True)
                                     IsCommiting = False
                                 End Sub
End Sub

Public Shared Function GetForceEndEdit(o As DependencyObject) As Boolean
    Return o.GetValue(ForceEndEditProp)
End Function

Public Shared Sub SetForceEndEdit(ByVal o As DependencyObject, ByVal value As Boolean)
    o.SetValue(ForceEndEditProp, value)
End Sub

This basicly force the grid to set IsEditing = false on the datagridrow, when any cell stops editing.