Silverlight 3: ComboBox, Cannot implicitly convert type

[King Chan]

using System;
using System.Windows.Controls;

namespace EventsHandling
{
    public partial class Page : UserControl
    {
        public Page()
        {
            InitializeComponent();

            Telerik.Windows.Controls.SelectionChangedEventHandler();
            RadComoBox.SelectionChanged += new EventHandler<SelectionChangedEventArgs>(radComboBox_SelectionChanged);

        }

        void radComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            message.Text = String.Format("{0} have been selected.", RadComoBox.Text);
        }

    }
}
)

Hi,

I am trying to let user select the item from combox and print out the combox item text.
So by doing that, I am subscribe the selection changed event to eventhandler.....

But it gives me the following error:
Error 1 Cannot implicitly convert type 'System.EventHandler<System.Windows.Controls.SelectionChangedEventArgs>' to 'Telerik.Windows.Controls.SelectionChangedEventHandler' C:\[Visual Studio 2008 Projects]\RadControlsSilverlightApplication1\RadControlsSilverlightApplication1\MainPage.xaml.cs 16 44 RadControlsSilverlightApplication1

And the above is my code...

I tried to follows the example for calendar from RadControls for Silverlight Document to attach the event handler but it gives the same error...

I am using:
Visual Studio 2008
Silverlight 3
RadControls for Silverlight Q3 2009 SP2
Windows XP Tablet PC Edition

Thanks

[Valeri Hristov]

Hello,

The event args of RadComboBox's SelectionChanged event are of different type, hence the error. You should change your code like this:
void radComboBox_SelectionChanged(object sender, Telerik.Windows.Controls.SelectionChangedEventArgs e)
{ 
    message.Text = String.Format("{0} have been selected.", RadComoBox.Text);
}

By the way, in case your code is not just a sample demonstrating the problem, there is a much easier way to update a TextBlock with the value of the Text property of RadComboBox, entirely in XAML:
<TextBlock Text="{Binding Text, ElementName=combo}" />
<telerikInput:RadComboBox x:Name="combo" ... />

Generally in Silverlight/WPF I would strongly recommend using bindings and ViewModels over handling the control events. The bindings will save you lots of lines of code.

Sincerely yours,
Valeri Hristov
the Telerik team

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[King Chan]

Thanks, it worked with using:
XAML:
<TextBlock Text="{Binding Text, ElementName=combo}" />
<telerikInput:RadComboBox x:Name="combo" ... />

But with changing SelectionChangedEventArgs  to Telerik.Windows.Controls.SelectionChangedEventArgs , it only resolved the error, but the "message" text block is not changing at all.
I want to use the selection changed event to trigger the RadCombox_SelectionChanged method, so I can do different things with the selected item value. (Yes, I want to do more complicate things)

I wonder if I made any mistake in my code?
MainPage.xaml.cs

using System;
using System.Windows.Controls;

namespace EventsHandling
{
    public partial class Page : UserControl
    {
        public Page()
        {
            InitializeComponent();

        }

        void RadComboBox_SelectionChanged(object sender, Telerik.Windows.Controls.SelectionChangedEventArgs e)
        {
            message.Text = String.Format("{0} have been selected.", RadComboBox.SelectedItem);
        }


    }
}

MainPage.xaml:

<UserControl xmlns:telerikInput="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Input"  x:Class="EventsHandling.Page"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480">
  <Grid x:Name="LayoutRoot">

        <StackPanel>
            <telerikInput:RadComboBox x:Name="RadComboBox" Text="- Select Item -">
                     <telerikInput:RadComboBoxItem x:Name="RadComboBoxItem" Content="ABC"/>
                <telerikInput:RadComboBoxItem x:Name="RadComboBoxItem2" Content="DEF"/>
                <telerikInput:RadComboBoxItem x:Name="RadComboBoxItem3" Content="GHI"/>
            </telerikInput:RadComboBox>
            <TextBlock x:Name="message"/>
        </StackPanel>

    </Grid>
</UserControl>

And a side question if you don't mind, I wonder if is possible that I can use this RadControl for Silverlight with JSP or PHP instead of ASP. Net?
Sorry, I am new to silverlight and Telerik products. :)

Thanks,
King

[Valeri Hristov]

Hi,

In your code the event handler is not attached. I guess that the following will resolve the problem:
<telerikInput:RadComboBox x:Name="RadComboBox" Text="- Select Item -" SelectionChanged="RadComboBox_SelectionChanged">
<telerikInput:RadComboBoxItem x:Name="RadComboBoxItem" Content="ABC"/>
<telerikInput:RadComboBoxItem x:Name="RadComboBoxItem2" Content="DEF"/>
<telerikInput:RadComboBoxItem x:Name="RadComboBoxItem3" Content="GHI"/>
</telerikInput:RadComboBox>


Sincerely yours,
Valeri Hristov
the Telerik team

Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking system and vote to affect the priority of the items.