Steve Clements

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steveclements Cool receipt!! http://yfrog...o4doj about 5 hours ago

steveclements @emewalton I was with 3 once...never ever ever again. about 1 day ago

steveclements soooooooooooo happy i didnt go with #orange and stayed with #02 about 1 day ago

steveclements Completed (Run): Distance 21.87 km, Duration 1:58:33, Pace 05:25 min/km, Speed 11.1 kph. #iMapMyRun about 3 days ago

steveclements I love this iPad, but not being able to view flash content is totally crap!! about 5 days ago

steveclements I just registered for The MOTI Mizuno Portishead Triathlon at https://regonline.activeeurope.com/the_moti_mizuno_portishead_triathlon about 18 days ago

steveclements out of interest...does anyone know when Bridge Valley Road will open again in #Bristol ??? about 19 days ago

steveclements Henleaze lake in #Bristol...what a hidden gem!! Love open water swimming now :) about 19 days ago

steveclements does anyone know the clifton susp bridge closure times this weekend for bikes/pedestrians?? #bristol #baloonfestival about 23 days ago

steveclements MapMyRide - Brecons 100 mile Route 2010 in: http://bit.ly/aHDcOD about 25 days ago

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November 2009 Entries

Silverlight: Working with ActualHeight & ActualWidth at Runtime

I came up against a problem, it seems like a pretty specific problem, but none the less the solution took me a while to figure out, so worth sharing!

My problem: I have a user control that contains some text among other things, but the text is of various length, the containing textblock therefore, like the user control has a dynamic height (set the Height property to System.Double.NaN).

There are n instances of the user control within a StackPanel, as a control is added to the StackPanel I want a StoryBoard which animates the Height and the Opacity. The Height of course I do not know.

So I need to the set the Value of the Double Animation at runtime.

The XAML for the StoryBoard.

Code Snippet

<Storyboard x:Name="sbExpandControl">
    <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="LayoutRoot" Storyboard.TargetProperty="(FrameworkElement.Height)">
        <EasingDoubleKeyFrame KeyTime="00:00:00" Value="0"/>
        <EasingDoubleKeyFrame KeyTime="00:00:02" Value="100" x:Name="expandToHeight"/>
    </DoubleAnimationUsingKeyFrames>
    <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="LayoutRoot" Storyboard.TargetProperty="(UIElement.Opacity)">
        <EasingDoubleKeyFrame KeyTime="00:00:00" Value="0"/>
        <EasingDoubleKeyFrame KeyTime="00:00:02" Value="1"/>
    </DoubleAnimationUsingKeyFrames>
</Storyboard>

Firstly I need to new up the user control, set all the properties, add the control to the StackPanel, set the height of the DoubleAnimation and fire the StoryBoard.

Just simply going UserControl.ActualHeight will return 0 because the layout engine has not calculated the ActualHeight property. Which is the problem!!!

So we need to use the Dispatcher class (you can find out more on MSDN).

Code Snippet

UserComment uc = new UserComment()
{
    Comments = v.Comments,
};
 
stkComments.Children.Insert(0, uc);
stkComments.Dispatcher.BeginInvoke(() =>
    {
        uc.ExpandControl();
    });

In the User Control (UserComment)

Code Snippet

public void ExpandControl()
{
    expandToHeight.Value = this.ActualHeight;
    sbExpandControl.Begin();
}

Hope this helps!

posted @ Sunday, November 29, 2009 11:50 PM | Feedback (1) | Filed Under [ Silverlight ]

Silverlight DataGrid: Scroll with mouse wheel…quick and dirty!

By Default scrolling with the mouse wheel is not enabled in the Silverlight DataGrid, actually I don’t think any control has it enabled.

Personally I think its pretty standard functionality for things to scroll with the mouse wheel.

So, I have got this little chunk of code that takes does the trick, nothing fancy going on here, but it works a treat.

Code Snippet

private void dgResults_MouseWheel(object sender, MouseWheelEventArgs e)
{
    if (!e.Handled)
    {
        int rowsToMove = 0;
        if (e.Delta < 0)
        {
            rowsToMove = e.Delta / 120 * -1;
        }
        else
        {
            rowsToMove = e.Delta / 120 * -1;
        }
 
        if (dgResults.SelectedIndex == 0
                || dgResults.SelectedIndex == (dgResults.ItemsSource.Cast<ItemSourceType>().ToList().Count - 1))
        { return; }
 
        dgResults.SelectedIndex = dgResults.SelectedIndex + rowsToMove;
        dgResults.ScrollIntoView(dgResults.SelectedItem, dgResults.Columns[0]);
    }
}

To explain a little…I found that my delta would change in multiples of 120, depending on how fast I scrolled, –120 if I scrolled down, +120 is I scrolled up. I needed to change this as if I scrolled down I needed the SelectedIndex to increase, so that’s what the first bit does.

Then I check that I’m not at either 0 or the last item in the datagrid, set the selected index and use the ScrollToView() method.

You may need to change slightly if you have horizontal scrolling, to stay with the correct column, for me having the first column is more than ideal, perfect in fact.

Note: This code has been tested nowhere except on my dev machine. So, here goes!!

.Net and then some....