UI problem when scrolling and Cell template with popup used.

[Valdo]

Hi, I've a following problem: i'm using custom date picker in cell template. If i open the picker popup and then scroll grid content - the popup will scroll out of bounds of the Grid. I've created a sample to demonstrate this.

MainPage.xaml

<UserControl x:Class="TestSL.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:Controls="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.GridView"
        xmlns:InputControls="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Input">
    <Grid>
        <Controls:RadGridView AutoGenerateColumns="False" ItemsSource="{Binding DateSource}" Width="400" Height="200">
            <Controls:RadGridView.Columns>
                <Controls:GridViewDataColumn Header="DatePicker" DataMemberBinding="{Binding}">
                    <Controls:GridViewDataColumn.CellTemplate>
                        <DataTemplate>
                            <InputControls:RadDatePicker SelectedDate="{Binding}" />
                        </DataTemplate>
                    </Controls:GridViewDataColumn.CellTemplate>
                </Controls:GridViewDataColumn>
            </Controls:RadGridView.Columns>
        </Controls:RadGridView>
    </Grid>
</UserControl>

MainPage.xaml.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;

namespace TestSL
{
    public partial class MainPage : INotifyPropertyChanged
    {
        private List<DateTime> _dateSource = new List<DateTime>();

        public MainPage()
        {
            InitializeComponent();
            DataContext = this;
            var source = new List<DateTime>();
            for (var i = 0; i < 20; i++)
            {
                source.Add(DateTime.Now.AddDays(i));
            }
            DateSource = source;
        }

        public List<DateTime> DateSource
        {
            get { return _dateSource; }
            private set
            {
                _dateSource = value;
                if (PropertyChanged != null)
                {
                    PropertyChanged(this, new PropertyChangedEventArgs("DateSource"));
                }
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
    }
}

Here are the steps:

1) Scroll to the bottom.

2) Click picker's button to open popup.

3) Hover any date picker (mouse wheel doesn't scroll without it for some reason).

4) Scroll grid up.

[Valdo]

Is there any fix or workaround for this?

[Yana]

Hello Valdo,

This reason for this issue is that RadDatePicker retains the focus when the dropdown is open - this behavior is by design.  In your case you can workaround it using MouseWheel event of the datapicker and manually closing the dropdown:

private void RadDatePicker_MouseWheel(object sender, MouseWheelEventArgs e)
{
    (sender as RadDatePicker).IsDropDownOpen = false;
}

Please let us know whether this helps.

Greetings,
Yana
the Telerik team