WPF Discussion Boards

Re: WCF: Message Security with a User Name Client - how to retrieve username+pwd from server side on a per request basis?

24-Mar-11 22:16

Hi I'm reading this article from MSDN regarding Message Security with a User Name Client
[^]

Two questions:
QUESTION 1 - Since no SSL, I take they don't encrypt using SSL cert but security context constructed AFTER authentication of client from server side using username+pwd? (Does it mean client send in pwd in clear text over the wire during initial exchange?! How does TLS negotiation work? What does it use as key for encryption? Server's got to publish her public key and client must know to use it to encrypt its initial transfer of username+pwd in order for initial exchange be secured. Here it says server need to expose a "Digital Certificate" (which I don't see in MSDN's diagram[^] - it's http, not https - what certificate?)

QUESTION 2 - how to check username and pwd from server side? This is how the sample set username/pwd from proxy/client side.

<br />
cc.ClientCredentials.UserName.UserName = ReturnUsername();<br />
cc.ClientCredentials.UserName.Password = ReturnPassword();<br />

But I don't see anything from server side anything which resembles this:

<br />
if(SomeRequestContext.UserName=="johndoe" && SomeRequestContext.Password=="abc123") // only if I can access username and pwd I can then implement any custom authorization<br />
{<br />
    IsAuthenticated = true;<br />
}<br />

From server side, I found two comes closest but no pwd and not sure if it's correct:

<br />
OperationContext.Current.ServiceSecurityContext.PrimaryIdentity.Name <br />
OperationContext.Current.ServiceSecurityContext.WindowsIdentity.User <br />

Also just a thought I don't think any of this[^] guards against say IP or arp spoofing this sort of attack?

What about replay attack (capture WCF request and resend) and mimic a license authorization or transaction for example.

Thanks!

REF: http://msdn.microsoft.com/en-us/library/ms752233.aspx[^]

dev

modified on Friday, March 25, 2011 4:31 AM

SledgeHammer0125-Mar-11 11:02

Re: WCF: Message Security with a User Name Client - how to retrieve username+pwd from server side on a per request basis?

25-Mar-11 11:02

By default, there is no authentication.

If you want authentication, they have a bunch of different ways to go. I won't go into all of them, but it sounds like you want the custom validator. In any event, most (if not all) require a cert and SSL / HTTPS. Otherwise you would send credentials over clear text which is a no-no.

For the custom validator, SecurityMode is set to "TransportWithMessageCredential" and <serviceCredentials> has a section similar to:

<userNameAuthentication userNamePasswordValidationMode="Custom" customUserNamePasswordValidatorType="x.y.Portal.UserNamePasswordValidator, Portal" />

UserNamePasswordValidator is a class you create that derives from UserNamePasswordValidator.

Thats just scratching the surface on the implementation details, I won't go into all of them since there are a lot (as with everything in WCF), but that should give you some good buzz words to google.

EDIT:

Oh yeah, forgot about your other question...

Once you get the password validator set up, you can get the username with:

ServiceSecurityContext.Current.PrimaryIdentity.Name

devvvy27-Mar-11 21:57

WrapPanel Bound To Collection

27-Mar-11 21:57

Thanks

And regarding TLS encryption and message integrity when Message level Security via UserName client ...[^], I found the answer (WCF client uses X509 cert to encrypt, WCF server uses public key to decrypt)[^]

The exact words from MSDN[^]are:

<br />
Since in the Internet scenario the client's message is transferred to the service over plain HTTP, it is vital to protect its content (both the client's credentials and the body of the message) by encrypting it. Encryption will provide for message integrity and privacy...<br />
Once the message is decrypted, WCF will read the client's credentials from the message, authenticate the client, and allow it to access the service. The real picture is a bit more complex, because WCF also needs to secure the reply messages and callbacks from the service to the client. One of the standards WCF supports deals with setting up such a secure conversation. In fact, several calls are made before the first request message from the client to the service, where WCF on the client's side generates a temporary shared secret it passes encrypted (using the service certificate) to the service. The client and the service will use that shared secret to protect all subsequent communication between them.<br />

REF:
Common Scenario[^]
Message security with UserName client[^]

dev

Kevin Marois24-Mar-11 12:09

24-Mar-11 12:09

I want to create a WrapPanel that has content loaded at runtime. I'd like the content to be in the form of buttons with a caption and an image. I found a Google hit here: http://stackoverflow.com/questions/2173105/wpf-bind-a-listt-as-the-contents-of-a-wrappanel[^]

When I try it, the content comes out as text. Anyone know how to do this?

Everything makes sense in someone's mind

Mycroft Holmes24-Mar-11 12:46

Mycroft Holmes

24-Mar-11 12:46

Kevin Marois wrote:
the content comes out as text

I found gettig the location of the images was the most finnicky requirement. This loads a horizontal wrap panel with images and caption, url comes from the database, images are stored locally.

<ItemsControl Grid.Row="1" ItemsSource="{Binding ShipList}" HorizontalAlignment="Center">
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <toolkit:WrapPanel/>
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <HyperlinkButton Click="HyperlinkButton_Click" Tag="{Binding Path=ShipID}" HorizontalContentAlignment="Center" >
                <Grid HorizontalAlignment="Center" >
                    <Grid.RowDefinitions>
                        <RowDefinition/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <Image Grid.Row="0" Stretch="None" Source="{Binding Path=ShipLogoUri}" />
                    <TextBlock Grid.Row="1" Foreground="Blue" Text="{Binding Path=Ship}" HorizontalAlignment="Center" />
                </Grid>
            </HyperlinkButton>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

Not sure if that is what you are after!

Never underestimate the power of human stupidity
RAH

Kevin Marois24-Mar-11 12:57

24-Mar-11 12:57

Perfect! Thank you

Everything makes sense in someone's mind

Kevin Marois24-Mar-11 13:29

24-Mar-11 13:29

Ok, this works great. The buttons all appear in the WrapPanel with text & images as they should, except for 2 issues:

1) I'm using telerik:RadRadioButtons. They're not acting like radio buttons now. ie - I can select one, all, or some.
2) The Command binding isn't working. Clicking the button does not get a response:

I think these problems are the result of the fact the list is dynamic and populatd at runtime. Any thoghts?

Here's the XAML:

<ItemsControl Grid.Row="1" 
                Grid.Column="0"
                Margin="10"
                ItemsSource="{Binding TemplateTypes}">
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <WrapPanel/>
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <telerik:RadRadioButton Command="{Binding SelectedTemplate}" 
                                    HorizontalContentAlignment="Center" 
                                    Height="175"
                                    Width="120">
                <Grid >
                    <Grid.RowDefinitions>
                        <RowDefinition/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <Image Grid.Row="0" 
                            Stretch="Fill"
                            Height="64"
                            Width="64"
                            Source="{Binding Path=ImageFile}" />
                    <TextBlock Grid.Row="1" 
                                Text="{Binding Path=Caption}" 
                                HorizontalAlignment="Center" 
                                TextWrapping="Wrap"/>
                </Grid>
            </telerik:RadRadioButton>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

And the code behind:

public class mv_FileNewViewModel : _ViewModelBase
{
    #region Properties
    private ObservableCollection<MenuButtonData> _TemplateTypes = new ObservableCollection<MenuButtonData>();
    public ObservableCollection<MenuButtonData> TemplateTypes
    {
        get { return _TemplateTypes; }
        set
        {
            if (_TemplateTypes != value)
            {
                _TemplateTypes = value;
                RaisePropertyChanged("TemplateTypes");
            }
        }
    }
    #endregion

    #region Command Properties
    private ICommand _SelectedTemplate;
    public ICommand SelectedTemplate
    {
        get
        {
            if (_SelectedTemplate == null)
                _SelectedTemplate = new RelayCommand(SelectedTemplateExecuted, SelectedTemplateCanExecute);

            return _SelectedTemplate;
        }
    }
    #endregion

    #region Command Handlers
    public bool SelectedTemplateCanExecute()
    {
        return true;
    }
    public void SelectedTemplateExecuted()
    {
        // THIS SHOULD FIRE WHEN A BUTTON IS CLICKED 
    }
    #endregion

    #region Private Methods
    private void loadTemplateTypes()
    {
        TemplateTypes.Add(new MenuButtonData { Caption = "Presentations", ImageFile = @"C:\Users\kmarois\Documents\My Dropbox\Raptor\Raptor\Media\Graphics\presentation_64x64.png" });
        TemplateTypes.Add(new MenuButtonData { Caption = "Slides", ImageFile = @"C:\Users\kmarois\Documents\My Dropbox\Raptor\Raptor\Media\Graphics\slide_48x52.png" });
        TemplateTypes.Add(new MenuButtonData { Caption = "Controls", ImageFile = @"C:\Users\kmarois\Documents\My Dropbox\Raptor\Raptor\Media\Graphics\control_72x72.png" });
        TemplateTypes.Add(new MenuButtonData { Caption = "Templates", ImageFile = @"C:\Users\kmarois\Documents\My Dropbox\Raptor\Raptor\Media\Graphics\template_32x32.png" });
        TemplateTypes.Add(new MenuButtonData { Caption = "Themes", ImageFile = @"C:\Users\kmarois\Documents\My Dropbox\Raptor\Raptor\Media\Graphics\theme_64x64.png" });
    }
    #endregion
}

Everything makes sense in someone's mind

SledgeHammer0124-Mar-11 14:06

24-Mar-11 14:06

It should work, unless:

1) your DataContext is not set right
2) telerik radio buttons are not using the Command interface and just using the Click event or something

Does the telerik radio button use the command when its just plopped on a form? If you use a real WPF radio button does the command handler get called?

In regards to your other issue of the radio buttons not being grouped, with the standard WPF radio buttons, you have to specifically set the group name for them to work like you expect. Its not done by tab order like in MFC anymore Smile | :)

. So I'd expect you have to set the group name on the telerik ones as well.

Kevin Marois24-Mar-11 14:25

24-Mar-11 14:25

Well, setting the groupname solved the issue of them not acting like radio buttons.

Before I implemented this template, I had the telerik:RadRadioButtons defined explicitly in the XAML, and the command was working, as was the grouping without setting the group name. So given that, I know the DC is set right.

So, I'm still not getting the Command to work right at this point.

Everything makes sense in someone's mind

SledgeHammer0124-Mar-11 15:10

24-Mar-11 15:10

Oh duh... I must have been smoking crack earlier...

You are inside of the DataTemplate, so {Binding} is pointing to your item, not the VM. In this case, its MenuButtonData.

Now, you wanted to be like the cool kids and use MVVM Smile | :)

, so you made your life a lot more difficult because you can't use RelativeSource / FindAncestor to get to where the property is.

I guess you could make the command a static property and refer to it that way, but then how would the static handler get to your VM?

Or you could try use RelativeSource / FindAncestor to get to your view if it has a reference to the ViewModel and then access the property through there. However that wouldn't be proper MVVM.

Your other option (which is what I do in my code) is to subscribe to the ItemContainerGenerator messages and when the container is generated for each item, use FindName to get to the RadioButton and hook up the command then.

The simplest way is to have the command in your view, but that ain't the best MVVM and it wouldn't really jive with your VM.

Its messy any way you do it.

SledgeHammer0124-Mar-11 15:13

24-Mar-11 15:13

Another idea I just had was that you can add a ref to the command inside of your MenuButtonData class and then you can use simple {Binding} in your DataTemplate and your MVVM wouldn't be broken.

You *would* have a random reference to a random command in a random place, but your other options are a lot messier.

And actually, maybe a command reference inside of MenuButtonData isn't so random...

Re: WrapPanel Bound To Collection [modified]

Mycroft Holmes24-Mar-11 15:50

Mycroft Holmes

24-Mar-11 15:50

This may be a really dumb response (I have not used radio buttons in SL yet, let alone Teleriks) but can't you add an IsChecked property to your observablecollection and track the change event on the list?

Never underestimate the power of human stupidity
RAH

Kim Breugelmans24-Mar-11 20:19

Kim Breugelmans

24-Mar-11 20:19

Try your binding like this:

<telerik:RadRadioButton Command="{Binding DataContext.SelectedTemplate, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ItemsControl}}}"
                        HorizontalContentAlignment="Center"
                        Height="175"
                        Width="120">

The DataContext of the items in your itemscontrol get set on the bound item, so you have to reference your itemscontrol as source.

modified on Friday, March 25, 2011 2:26 AM

Kevin Marois25-Mar-11 5:43

25-Mar-11 5:43

That did it. Thank you!!!

The only question now is how to determine which RadioButton was clicked?

Everything makes sense in someone's mind

SledgeHammer0125-Mar-11 6:32

25-Mar-11 6:32

Its not in sender, OriginalSource, etc? That'll just get you the RadioButton though. I'm thinking one step ahead of you here... you aren't interested in which RadioButton was clicked, you are interested in which MenuItemData was selected, right? In that case, just use CommandParameter={Binding} to pass your MenuItemData into your command handler.

Kevin Marois25-Mar-11 7:07

25-Mar-11 7:07

Ok, here's the XAML:

<telerik:RadRadioButton Command="{Binding DataContext.SelectedTemplate,
                            RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ItemsControl}}}"                        
                        CommandParameter="{Binding}"
                        HorizontalContentAlignment="Center"                        
                        Height="175"                        
                        Width="120"
                        GroupName="TemplateButtons">

and here's the C#:

private ICommand _SelectedTemplate;
public ICommand SelectedTemplate
{
    get
    {
        if (_SelectedTemplate == null)
            _SelectedTemplate = new RelayCommand(SelectedTemplateExecuted, SelectedTemplateCanExecute);

        return _SelectedTemplate;
    }
}

public bool SelectedTemplateCanExecute()
{
    return true;
}
public void SelectedTemplateExecuted()
{
    loadView(InnerViews.Presentations);
}

How/where is the MenuItemData reference passed?

Everything makes sense in someone's mind

Ok Everyone, Here It Is

Kevin Marois25-Mar-11 7:31

25-Mar-11 7:31

This now works.

First the XAML:

<telerik:RadRadioButton Command="{Binding DataContext.SelectedTemplate, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ItemsControl}}}"                        
                        CommandParameter="{Binding Path=DataContext, RelativeSource={RelativeSource Self}}"
                        HorizontalContentAlignment="Center"                        
                        Height="175"                        
                        Width="120"
                        GroupName="TemplateButtons">

Now the code behind:

private ICommand _SelectedTemplate;
public ICommand SelectedTemplate
{
    get
    {
        if (_SelectedTemplate == null)
            _SelectedTemplate = new RelayCommand<MenuButtonData>(SelectedTemplateExecuted, SelectedTemplateCanExecute);

        return _SelectedTemplate;
    }
}
public bool SelectedTemplateCanExecute(object Parameter)
{
    return true;
}
public void SelectedTemplateExecuted(object Parameter)
{
            
}

Adding the Type qualifier to the RelayCommand and setting up the CanExecute and Executed methods to receive the parameter is what did it. Now, when a radiobutton is clicked, it's bound data item is passed to the command methods.

Many thanks to all of you.

Everything makes sense in someone's mind

Kim Breugelmans25-Mar-11 7:04

Kim Breugelmans

25-Mar-11 7:04

my colleague at work has some helper class for it, but I'm not at work anymore so can't look at it right now...
but I think he has a generic wrapper class Option<t> with an IsSelected property
So maybe you could try to add an IsSelected property to your MenuButtonData class and bind it to your
IsSelected of your radio button?
This is just guessing as I don't even know the RadRadioButton control.
Would CommandParameter={Binding} return the control or DataContext?
Wouldn't it need to be CommandParameter={Binding Path=DataContext, RelativeSource={RelativeSource Self}} to return the MenuButtonData?
Again just guessing, don't even have VS at home Wink | ;-)

SledgeHammer0125-Mar-11 9:30

WPF binding to a simple CLR Property? (Visibility=Collapsed)

25-Mar-11 9:30

Thats kind of a slick way to get to the VM. I'll have to remember that.

devvvy23-Mar-11 16:23

Re: WPF binding to a simple CLR Property? (Visibility=Collapsed)

23-Mar-11 16:23

Hi
I have trouble getting WPF binding to a simple CLR Property to work (Visibility=Collapsed)

<Button Name="btnSomeCmd" HorizontalAlignment="Left" Grid.Row="0" Grid.Column="3" Click="btnSomeCmd_Click" Width="25px" Height="25px" Visibility="{Binding Path=IsSomeCmdVisible}" >

public partial class SomeUserControl : UserControl
{
...
public Visibility IsSomeCmdVisible
{
get { return Visibility.Collapsed; }
}
...
}

sigh, WPF makes it so hard to get simple things work. (I got it working with dependency property but simple CLR... anyone please write an article on this)

dev

devvvy23-Mar-11 19:42