Hello Telerik team,

I`ve faced an issue with GridView. Once when I resize the column it throws NullReferenceException with the following stack trace

   at Telerik.Windows.Controls.GridView.GridViewHeaderCell.HeaderToResize(Object gripper)
   at Telerik.Windows.Controls.GridView.GridViewHeaderCell.OnColumnHeaderResize(Object sender, DragDeltaEventArgs e)
   at System.Windows.Controls.Primitives.DragDeltaEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
   at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
   at System.Windows.Controls.Primitives.Thumb.OnMouseMove(MouseEventArgs e)
   at System.Windows.UIElement.OnMouseMoveThunk(Object sender, MouseEventArgs e)
   at System.Windows.Input.MouseEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
   at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
   at System.Windows.Input.InputManager.ProcessStagingArea()
   at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
   at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
   at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
   at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
   at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
   at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
   at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
   at System.Windows.Threading.Dispatcher.Run()
   at System.Windows.Application.RunDispatcher(Object ignore)
   at System.Windows.Application.RunInternal(Window window)
   at System.Windows.Application.Run()
   at WpfApp1.App.Main()

Here is an example project to help you to reproduce this issue.

Steps to reproduce:

1. Resize the "Phone" column to increase its size, do it far outside of the application window
2. Resize the "Comments" column to increase its size, do it far outside of the application window
3. Resize the "Description" column to increase its size, do it far outside of the application window
4. Resize the "Name" column to increase its size, do it far outside of the application window

And at some moment the application should throw NullReferenceException.

Please look at this one or let me know if I did something wrong.

Hello,

I created the ColumnsVisibility attached property to the RadGridView.

When the user clicks the columns' header, I open a context menu that shows all the columns.

Then the user can show/hide the columns by updating the IsVisible property. I am interested to add a button to the left of the first columns header.

The new button will open the Context Menu instead of clicking the Column Header.

I need this functionality because if the users hides all the colums, then there is no header and he will not able to open the menu at all, which means the columns visibilty can't be restored.

I can't attach the property to the RadGridView itself because I have another menu there.

A better solution may be to add this attached property to another style of a control part in the RadGridView template.

I am wondering if there is another control in your template (under the GridViewColumnHeader).

At the end I need to open a context menu in the top of the RadGridView but in parallel to open a different ContextMenu when the user clicks and empty space in the rest of the RadGridView (middle/bottom).

We are looking to migrate to latest telerik ui for wpf. Could you please suggest on compatibility of framework with .net version.

currently we use .Net framework 4.6.2.

I would like to create a custom "control" that is a subclass of "RadTabItem" and use it as the default tab class.

I know I can tie into the AddingNewTab event and effect the Item property of the event args, but that would be a UI Element in the ViewModel (VM) of a MVVM and I would like to keep the UI element strictly in the UI code (not in the VM).

Is there some way to specify (perhaps via .Resources) the class for a new tab created by clicking the "+" in the RadTabbedWindow.

e.g.  something like the a "DefaultTab" element.

          <DefaultTab Type="{x:Type MyTabClass}"/>

of the below

<telerik:RadTabbedWindow x:Class="PickCart.Client.Zza.Desktop.Tabs.TabbedView" 
                         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
                         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
                         xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
                         xmlns:client="clr-namespace:PickCart.Client"
                         xmlns:b="http://schemas.microsoft.com/xaml/behaviors"
                         Width="1024"
                         Height="800">
    <b:Interaction.Triggers>
        <b:EventTrigger EventName="AddingNewTab">
            <b:CallMethodAction TargetObject="{Binding}" MethodName="OnAddingNewTab"/>
        </b:EventTrigger>
    </b:Interaction.Triggers>
    <telerik:RadTabbedWindow.DataContext>
        <client:TabbedViewModel/>
    </telerik:RadTabbedWindow.DataContext>
    <telerik:RadTabbedWindow.Resources>
          <DefaultTab Type="{x:Type MyTabClass}"/>
    </telerik:RadTabbedWindow.Resources>
    <telerik:RadTabItem Header="Main" CloseButtonVisibility="Hidden">
        <TextBlock Text="This is the main tab" />
    </telerik:RadTabItem>
</telerik:RadTabbedWindow>

In our app.xaml.cs we have been using this.MainWindow = new MyMainWindow().

We are trying to switch to a RadTabbedWindow, but RadTabbedWindow is not a Window, it is a UserControl.  What would be a way to use this and keep the this.MainWIndow?

WPF TabbedWindow - Getting Started - Telerik UI for WPF

Hello,

In our application, we need to add header to each pages when exporting the grid(RadGridView) into the workbook using ExportToWorkBook. 
I tried to use the option mentioned in "https://docs.telerik.com/devtools/document-processing/libraries/radspreadprocessing/features/headers-and-footers#headerfootersection" to fix this, but it is not work as expected.

Please see the attached image of our requirement and provide information on how to achieve this ?

Thanks in advance.

Hello,

I am insterested on change the RadDateTimePicker.

1. When set the control to change the minutes/seconds, the default control template shows all the possible options in buttons, a little bit annoying for the user.

The request: like Android, the user wants three numbers (hour, minute, seconds) that he can move up/down. Instead of scrolling we can use up/down arrows.

2. Add a button in the control to change 12/24 format and visibilty property for this button.

Questions:

1. Which approach do you suggest?

Override all the TimeControl template? or update tue default style ?

2. Which properties should I bind in case that I override the TimePicker to create a new template with three up down controls where each control will handle hours/minutes/seconds ?

3. Do you have any control that can set the number value with up down like Android (see attached picture)

4. For point 2, how can I add a control that will be set the date time format off the original RadTimePicker? 

I am not sure that creating a new custom control which contains the new control and telerik control will be the best approach. I want to add the control to the original one in the style.

5. Which property should be set to show 24 format. In the example you are showing a property that doesn't update the time correctly.

6. Do you have advanced examples with many styles and changes on Control Template ?

All the examples on the site are quiet simple, maybe did you get from users new examples.

Thanks,

This forum is so helpful.

Hello,

I have a RadGridView with a model that may have some errors. In case of error, the row border is red and the row background is transparent. In this case, when having many rows with errors, the user can't know which row is selected because the blue background which indicates that the row is selected, dissapears on error.

How can I fix the Error Template to show also the error red border and the IsSelected blue background?

Hello Telerik Team,

I want to access the Click event or MouseLeftButtonDown event for each Filter icon of the RadGridView Columns.

Please give us a sample application to do that.

Hello,

I have a RadGridView with 5,000 rows and 20 columns with virtualization enabled. I have the grid on the left side of the main window (fixed position).

I added a button.

When the user clicks the button, it will open a new window and the grid should move to the new window.

Somemehow the performance is too slow. 

As mentioned I an using virtualization, regular window, no styles and it tooks like 2-3 seconds to open the window.  The cells'  values may change but not too much. I tried to call the Show() method first and give to the window fixed width and height, also for the RadGridView but when I do the following:

window.Content = radGridView

It takes a while to skip that line. 

Do you have any advice? and/or a sample application with a similar behavior that doesn't have this performance issue? I can use it to compare with my code.