In this case, the RadListView control is placed inside a RadSplitContainer. The control is set in DetailsView with enabled TextWrap of the cells. When the splitter is moved the cells with longer text are not sized correctly.
In this case, we need to force the cells to measure again. To do that we can call the InvalidateMeasure() with true as a parameter and call UpdateLayout() afterward of the ListViewElement.
this.radListView1.ListViewElement.InvalidateMeasure(true);
this.radListView1.ListViewElement.UpdateLayout();
Use the attached project and start dragging an item to trigger scrolling. As a result, an error occurs. The attached gif file illustrates the steps.
Workaround:
Me.RadListView1.ListViewElement.DragDropService = New CustomListViewDragDropService(Me.RadListView1.ListViewElement) Public Class CustomListViewDragDropService
Inherits ListViewDragDropService
Public Sub New(owner As RadListViewElement)
MyBase.New(owner)
End Sub
Protected Overrides Sub OnPreviewDragOver(e As RadDragOverEventArgs)
MyBase.OnPreviewDragOver(e)
End Sub
Protected Overrides Sub HandleMouseMove(mousePos As Point)
If Not Me.Initialized Then
MyBase.HandleMouseMove(mousePos)
End If
Dim mi As MethodInfo = GetType(RadDragDropService).GetMethod("DoDrag", BindingFlags.Instance Or BindingFlags.NonPublic)
mi.Invoke(Me, New Object() {mousePos})
Dim fi2 As FieldInfo = GetType(RadDragDropService).GetField("beginPoint", BindingFlags.Instance Or BindingFlags.NonPublic)
fi2.SetValue(Me, mousePos)
Dim fi As FieldInfo = GetType(ListViewDragDropService).GetField("dragHintWindow", BindingFlags.Instance Or BindingFlags.NonPublic)
Dim dragHintWindow = fi.GetValue(Me)
If dragHintWindow Is Nothing AndAlso Me.CanCommit Then
Me.PrepareDragHint()
End If
Me.UpdateDragHintLocation(mousePos)
Dim viewElement As RadListViewElement = Me.Owner
Dim item As BaseListViewVisualItem = TryCast(Me.DropTarget, BaseListViewVisualItem)
If item IsNot Nothing AndAlso item.Data IsNot Nothing AndAlso Not item.Data.Owner.Equals(viewElement) Then
viewElement = item.Data.Owner
End If
Dim clientPos As Point = viewElement.PointFromScreen(mousePos)
If (clientPos.Y < 0 AndAlso viewElement.ViewElement.Orientation = Orientation.Vertical) OrElse (clientPos.X < 0 AndAlso viewElement.ViewElement.Orientation = Orientation.Horizontal) Then
viewElement.ViewElement.Scroller.Scrollbar.PerformSmallDecrement(1)
ElseIf (clientPos.Y > viewElement.Size.Height AndAlso viewElement.ViewElement.Orientation = Orientation.Vertical) OrElse (clientPos.X > viewElement.Size.Width AndAlso viewElement.ViewElement.Orientation = Orientation.Horizontal) Then
viewElement.ViewElement.Scroller.Scrollbar.PerformSmallIncrement(1)
End If
End Sub
End Class
2. Add a few ListViewDataItems
3. Run the app and inspect the control with the inspect.exe tool
You will see that the last item is not accessible by the tool.
Note that if you hide the column headers (ShowColumnHeaders property) you will be able to access all ListViewDataItems.
System.NullReferenceException: 'Object reference not set to an instance of an object.' when removing items from the list:
public Form1()
{
InitializeComponent();
for (var i = 0; i < 30; i++)
{
var item = new ListViewDataItem();
radListView2.Items.Insert(0, item);
item[0] = i;
item[1] = i;
item[2] = i;
item[3] = i;
}
}
private void radButton1_Click(object sender, EventArgs e)
{
try
{
radListView2.BeginUpdate();
foreach (var lvi in radListView2.Items.ToArray())
{
radListView2.Items.Remove(lvi);
}
}
finally
{
radListView2.EndUpdate();
}
}
Just to report a little typo in RadListViewElement:
Protected Overrides Sub OnCurrecntItemChanged(args As ListViewItemEventArgs)
Thanks.
This problem is even reproducible in our Demo application >> Virtual Grid >> Web service example. You will notice that when you scroll to the bottom, the waiting indicator is not being animated when the DPI scaling is higher than 100%.
If you apply the same gif file in a PictureBox it gets animated when using 150% DPI scaling.
Please refer to the attached sample project and follow the steps illustrated in the gif file.
Note: if the vertical scrollbar is visible, the editor is activated as expected.
Workaround:
Me.RadListView1.ItemSize = New Size(200, 30)