Fix: XAML – The member Content is not recognized or is not accessible

I was looking into some third-party code, upgrading it from Silverlight 4.x and was getting error ‘The member "Content" is not recognized or is not accessible’ at the following code part:

Looking it up, found that you don’t need to bind the Content property of a ContentPresenter at all if you put it inside the ControlTemplate of a ContentControl (a Button is such too).

Quoting from:

http://social.msdn.microsoft.com/Forums/silverlight/en-US/ee6e887d-5140-4d32-a532-3d16b7d879da/how-do-i-bind-contentpresenter-content?forum=silverlightarchieve

 

When you put a ContentPresenter in the ControlTemplate of a ContentControl, it automatically displays the Content of the templated control. For example, if you put a ContentPresenter in a ControlTemplate of a Button, the Content property of the ContentPresenter is implicitly bound to the Content of the Button that uses the ControlTemplate.

It is introduced in this MSDN article and have a sample in it, http://msdn.microsoft.com/en-us/library/system.windows.controls.contentpresenter.content(v=vs.95).aspx

HowTo: Save screenshot of a control hosted on a WinForm

I’m trying to automate grabbing of activity screenshots from ClipFlair Activity Gallery, but most command-line screen capturing tools, like SiteShoter and IECapt fail to get an image from Silverlight content (they get just a background color).

Some other opensource tool that I could tweek was ThumbPage, but  that didn’t support command-line and needed to disable Silverlight hardware acceleration in the webpage source (that is not define enableGPUAcceleration Silverlight param or set it to false) to grab the Silverlight content too in the image. This is probably because that tool was written in VB6 and must be using plain GDI instead of GDI+ or other newer graphics API, but I’m not sure if that’s the issue with the h/w acceleration.

So, I started making my own WinForms-based tool in Visual Studio. The following sample code is based on ArsenMkrt’s reply at StackOverflow, but this one allows you to capture a control in your form (my tool has a WebBrowser control in it and want to capture just its display). Note the use of PointToScreen method:

//Project: WebCapture
//Filename: ScreenshotUtils.cs
//Author: George Birbilis (http://zoomicon.com)
//Version: 20130820

using System.Drawing;
using System.Windows.Forms;

namespace WebCapture
{
  public static class ScreenshotUtils
  {

    public static Rectangle Offseted(this Rectangle r, Point p)
    {
      r.Offset(p);
      return r;
    }

    public static Bitmap GetScreenshot(this Control c)
    {
      return GetScreenshot(new Rectangle(c.PointToScreen(Point.Empty), c.Size));
    }

    public static Bitmap GetScreenshot(Rectangle bounds)
    {
      Bitmap bitmap = new Bitmap(bounds.Width, bounds.Height);
      using (Graphics g = Graphics.FromImage(bitmap))
        g.CopyFromScreen(new Point(bounds.Left, bounds.Top), 
                         Point.Empty, bounds.Size);
      return bitmap;
    }

    public const string DEFAULT_IMAGESAVEFILEDIALOG_TITLE = "Save image";
    public const string DEFAULT_IMAGESAVEFILEDIALOG_FILTER = 
"PNG Image (*.png)|*.png|JPEG Image (*.jpg)|*.jpg|Bitmap Image (*.bmp)|
*.bmp|GIF Image (*.gif)|*.gif";

//*** NOTE: the string above is a single line, split it for posting here ***//

    public static SaveFileDialog GetImageSaveFileDialog(
      string title = DEFAULT_IMAGESAVEFILEDIALOG_TITLE, 
      string filter = DEFAULT_IMAGESAVEFILEDIALOG_FILTER)
    {
      SaveFileDialog dialog = new SaveFileDialog();

      dialog.Title = title;
      dialog.Filter = filter;

      return dialog;
    }

    public static void ShowSaveFileDialog(this Image image, 
                                          IWin32Window owner = null)
    {
      using (SaveFileDialog dlg = GetImageSaveFileDialog())
        if (dlg.ShowDialog(owner) == DialogResult.OK)
          image.Save(dlg.FileName);
    }

  }
}

Note the “using” clause above, it makes sure that the local variable g of type Graphics is Disposed immediately after the respective clause exits, instead of leaving any allocated resources for the garbage collector to handle. Plus the compiler makes sure the “g” variable isn’t use at the following code in that method by mistake (which could occur if you disposed it there by hand instead).

Having the Bitmap object you can just call Save on it:

private void btnCapture_Click(object sender, EventArgs e)
{
  webBrowser.GetScreenshot().Save("C://test.jpg", ImageFormat.Jpeg);
}

The above assumes the Garbage Collector (aka GC) will grab the bitmap, but maybe it’s better to assign the result of someControl.getScreenshot() to a Bitmap variable, then dispose that variable manually when finished, especially if you’re doing this grabbing often (say you have a list of webpages you want to load and save screenshots of them):

private void btnCapture_Click(object sender, EventArgs e)
{
  Bitmap bitmap = webBrowser.GetScreenshot();
  bitmap.ShowSaveFileDialog();
  bitmap.Dispose(); //release bitmap resources
}

 

Update:

Now WebCapture tool is ClickOnce-deployed from the web (also has nice autoupdate support thanks to ClickOnce) and you can find its source code at http://ClipFlair.codeplex.com.

Speaking of ClickOnce, I noticed that if at the autoupdate dialog shown when you launch the app from its desktop shortcut (and there’s a new version available) you press “Skip”, it won’t offer you this update anymore when you launch an app (I hope that when an even newer update is there it will prompt you), but you can override that behaviour by going to the installation page for your ClickOnce app (where you installed it from in the first place) and press the “Install” button there.

HowTo: Bind ASP.net control to list of files or folders

At ClipFlair Gallery metadata input pages for Activities and Clips I had to bind an ASP.net control to a list of files and folders respectively and although I found a Folder Contents DataSource control, it didn’t cover my needs (like filtering of a folder contents).

I just contributed my solution using .NET Anonymous Types and LINQ (assumes a using System.Linq clause) to:

http://stackoverflow.com/questions/1331793/bind-repeater-to-a-list-of-files-and-or-folders

private string path = HttpContext.Current.Server.MapPath("~/activity");

   protected void Page_Load(object sender, EventArgs e)
   {      
     if (!IsPostBack) { //only at page 1st load
       listItems.DataSource = 
         Directory.EnumerateFiles(path, "*.clipflair")
                  .Select(f => new { Filename=Path.GetFileName(f) });

       listItems.DataBind(); //must call this
     }
   }

The above snippet gets all *.clipflair files from ~/activity folder of a web project

Update: using EnumerateFiles (availabe since .NET 4.0) instead of GetFiles since this is more efficient with LINQ queries. GetFiles would return a whole array of filenames in memory before LINQ had a chance to filter it.

The following snippet shows how to use multiple filters, which GetFiles/EnumerateFiles don’t support themselves:

private string path = HttpContext.Current.Server.MapPath("~/image");
private string filter = "*.png|*.jpg";

protected void Page_Load(object sender, EventArgs e)
{
  _listItems = listItems; 
  
  if (!IsPostBack)
  {
    listItems.DataSource =
      filter.Split('|').SelectMany(
        oneFilter => Directory.EnumerateFiles(path, oneFilter)
                     .Select(f => new { Filename = Path.GetFileName(f) })
      );

    listItems.DataBind(); //must call this

    if (Request.QueryString["item"] != null)
      listItems.SelectedValue = Request.QueryString["item"];
                          //must do after listItems.DataBind
  }
}

The snippet below shows how to get all directories from /~video folder and also filters them to select only directories that contain a .ism file (Smooth Streaming content) with the same name as the directory (e.g. someVideo/someVideo.ism)

using System;
using System.IO;
using System.Linq;
using System.Web;
using System.Web.UI.WebControls;

namespace ClipFlair.Gallery
{
 public partial class VideoMetadataPage : System.Web.UI.Page
 {

  private string path = HttpContext.Current.Server.MapPath("~/video");

  protected void Page_Load(object sender, EventArgs e)
  {
    if (!IsPostBack) { //only at page 1st load
      listItems.DataSource = 
       Directory.GetDirectories(path)
        .Where(f =>(Directory.EnumerateFiles(f,
                              Path.GetFileName(f)+".ism").Count()!=0))
        .Select(f => new { Foldername = Path.GetFileName(f) });
      //when having a full path to a directory don't use Path.GetDirectoryName 
      //(gives parent directory),
      //use Path.GetFileName instead to extract the name of the directory

      listItems.DataBind(); //must call this
    }
  }

 

The examples above are from a DropDownList, but it’s the same logic with any ASP.net control that supports Data Binding (note I’m calling Foldername the data field at the 2nd snippet and Filename at the 1st one, but could use any name, need to set that in the markup):

        <asp:DropDownList ID="listItems" runat="server" AutoPostBack="True" 
          DataTextField="Foldername" DataValueField="Foldername" 
          OnSelectedIndexChanged="listItems_SelectedIndexChanged"
          />

Fix: The tag ‘TimeUpDown’ does not exist in XML namespace (Silverlight Toolkit)

If you use TimeUpDown control from Silverlight Toolkit in your XAML like below (copy pasting from CaptionGrid at ClipFlair source):

<ResourceDictionary

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

>

  <DataTemplate x:Key="StartTimeCellTemplate">

    <TextBlock Margin="4" Text="{Binding Begin}" />

  </DataTemplate>



  <DataTemplate x:Key="StartTimeCellEditTemplate">

    <input:TimeUpDown Format="hh:mm:ss"

Value="{Binding Begin, Mode=TwoWay, ValidatesOnExceptions=True, NotifyOnValidationError=true}"

    />

  </DataTemplate>

…


</ResourceDictionary>

then even though it seems to not complain in the XAML designer of Visual Studio 2010, then at Build time, even if you’ve added a reference to System.Windows.Controls.Input.Toolkit assembly (the 5.0.5.0 version for the Silverlight 5 Toolkit [December 2011 release]), you get:

The tag ‘TimeUpDown’ does not exist in XML namespace ‘clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Input.Toolkit’

 

Similar bad behaviour occurs if you try to drag-drop the TimeUpDown control from Visual Studio toolbar (assuming you’ve installed the Silverlight Toolkit first) onto the XAML designer, no xml namespace (named xmlns:input above) is added and you just get <TimeUpDown /> in the designer.

 

The solution is to also add to your project a reference to System.Windows.Controls assembly (be sure to select same version DLL as above [e.g. 5.0.5.0]). For some reason the System.Windows.Controls.Input.Toolkit doesn’t seem to pull that together and must have some internal dependency to it (although the error you get is very cryptic).

Below is the Add Reference dialog of Visual Studio 2010, you either use the “Extensions” from the right handside, or type-in “System.Windows.Controls” at the search box to quickly spot those two assemblies.

 

Note that If you have a Silverlight assembly project with some UserControl in it and you apply the workaround I mentioned above, then if you use that UserControl in a Silverlight app (in a Page or other UserControl) you get a RUNTIME error this time at launch saying XamlParserError at the title bar and the exception text:

The type ‘TimeUpDown’ was not found because ‘clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Input.Toolkit’ is an unknown namespace

This time the fix is to add a reference to "System.Windows.Controls.Input.Toolkit" to the project.

The funny thing is that this project (that uses a library that hosts a control that uses TimeUpDown itself) DOESN’T NEED to have a reference to "System.Windows.Controls", as the library does need to compile.

The other funny thing is that it does compile OK without adding the "System.Windows.Controls.Input.Toolkit" reference, but it shows runtime error.

 

This issue has been reported for some time now at:

https://connect.microsoft.com/VisualStudio/feedback/details/664106/silverlight-forum-sl5-numericupdown-control-compile-error

but hasn’t yet been fixed.

Update:

This may also be related:

https://zoomicon.wordpress.com/2012/07/02/fix-the-tag-xxx-does-not-exist-in-xml-namespace-clr-namespaceyyy/

I noticed that when I tried to compile on a machine that didn’t have Silverlight 5 Toolkit, it was eventually trying to use the Silverlight 4 Toolkit version of System.Windows.Control.Input from my Debug folder (not sure how that DLL ended up there, probably was brought in automatically via some other library’s dependencies by Visual Studio). So maybe you end up with multiple assemblies with the same name in the project and you have to remove the old ones.

You may also run into this issue if your solution was using Silverlight 5 Toolkit and you try to build the project on another machine that has Silverlight 4 Toolkit only. Solution is to install Silverlight 5 Toolkit too and then make sure the project refers to the 5.0 version of System.Windows.Controls.Input.Toolkit.dll and that the reference doesn’t have a path that points into your solution but to the program files folder instead, where Silverlight Toolkit gets installed.

HowTo: Load a XAML ResourceDictionary from a .NET assembly

Copying here my answer at:

http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/11a42336-8d87-4656-91a3-275413d3cc19

What seems to work for me is the following (copying from the source code of http://ClipFlair.codeplex.com [check out the FlipPanel project under “Client” subfolder])

note

I’m using Build Action = "Page" and Custom Tool="MSBuild:Compile" at the properties of Themes\DropDownTheme.xml and Themes\RotateHorizontalTheme.xaml, as was for Themes\Generic.xaml. Seems to work OK (probably this is faster at runtime compared to setting Build Action to Resource and telling it to not build it)

according to http://stackoverflow.com/questions/145752/what-are-the-various-build-action-settings-in-vs-net-project-properties-and-wh the Build Action = "Page" compiles the XAML into BAML (this seems to also apply to Silverlight 5)

* FlipPanel project, Themes\Generic.xaml

<ResourceDictionary
 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 xmlns:local="clr-namespace:FlipPanel;assembly=FlipPanel">
 
  <ResourceDictionary.MergedDictionaries>
    <ResourceDictionary 
             Source="/FlipPanel;component/Themes/RotateHorizontalTheme.xaml" />
  </ResourceDictionary.MergedDictionaries>
 
  <Style TargetType="local:FlipPanel">
    <Setter Property="Template" 
            Value="{StaticResource FlipPanel_RotateHorizontalTemplate}"/>
  </Style>
 
</ResourceDictionary>

* FlipPanel Project, Themes\RotateHorizontalTheme.xaml

<ResourceDictionary
 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 xmlns:local="clr-namespace:FlipPanel;assembly=FlipPanel">
 
  <ControlTemplate x:Key="FlipPanel_RotateHorizontalTemplate" 
                             TargetType="local:FlipPanel">
    <Grid>
     ... 
    </Grid>
  </ControlTemplate>
 
  <Style x:Key="FlipPanel_RotateHorizontalStyle" TargetType="local:FlipPanel">
    <Setter Property="Template" 
            Value="{StaticResource FlipPanel_RotateHorizontalTemplate}"/>
  </Style>
 
</ResourceDictionary>
  

* FlipPanel Project, Themes\DropDownTheme.xaml

<ResourceDictionary
 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 xmlns:local="clr-namespace:FlipPanel;assembly=FlipPanel">
 
  <ControlTemplate x:Key="FlipPanel_DropDownTemplate" 
                         TargetType="local:FlipPanel">
    <Grid>
     ... 
    </Grid>
  </ControlTemplate>
 
  <Style x:Key="FlipPanel_DropDownStyle" TargetType="local:FlipPanel">
    <Setter Property="Template" 
            Value="{StaticResource FlipPanel_DropDownTemplate}"/>
  </Style>
 
</ResourceDictionary>
  

* FlipPanel.Silverlight.Demo project, FlipPanelTest.xaml

<UserControl x:Class="FlipPanelTest.FlipPanelTest"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:flip="clr-namespace:FlipPanel;assembly=FlipPanel" >
 
  <UserControl.Resources>
    <ResourceDictionary>
      <ResourceDictionary.MergedDictionaries>
        <ResourceDictionary 
             Source="/FlipPanel;component/Themes/RotateHorizontalTheme.xaml" />
        <ResourceDictionary 
                     Source="/FlipPanel;component/Themes/DropDownTheme.xaml" />        
      </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
  </UserControl.Resources>
 
  <Grid x:Name="LayoutRoot" Background="White" Width="400">
 
    <Grid.RowDefinitions>
      <RowDefinition Height="300"></RowDefinition>
      <RowDefinition Height="300"></RowDefinition>
    </Grid.RowDefinitions>
 
    <flip:FlipPanel x:Name="panel1" Grid.Row="0" BorderBrush="DarkOrange"
         BorderThickness="3"
         CornerRadius="4" Margin="10" Background="White" 
         Template="{StaticResource FlipPanel_DropDownTemplate}" > 
                <!-- Style="{StaticResource FlipPanel_DropDownStyle}" -->
      <flip:FlipPanel.FrontContent>
        <StackPanel Margin="6">
          <TextBlock TextWrapping="Wrap" Margin="3" FontSize="16" 
            Foreground="DarkOrange"
            >This is the front side of the FlipPanel.</TextBlock>
          <Button Margin="3" Padding="3" Content="Button One"></Button>
          <Button Margin="3" Padding="3" Content="Button Two"></Button>
          <Button Margin="3" Padding="3" Content="Button Three"></Button>
          <Button Margin="3" Padding="3" Content="Button Four"></Button>
        </StackPanel>
      </flip:FlipPanel.FrontContent>
      <flip:FlipPanel.BackContent>
        <Grid Margin="6">
          <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition></RowDefinition>
          </Grid.RowDefinitions>
          <TextBlock TextWrapping="Wrap" Margin="3" FontSize="16" 
                  Foreground="DarkMagenta"
                >This is the back side of the FlipPanel.</TextBlock>
          <Button Grid.Row="2" Margin="3" Padding="10" 
              Content="Flip Back to Front" HorizontalAlignment="Center" 
              VerticalAlignment="Center" Click="cmdFlip1_Click"></Button>
        </Grid>
      </flip:FlipPanel.BackContent>
    </flip:FlipPanel>
 
    <flip:FlipPanel x:Name="panel2" Grid.Row="1" BorderBrush="DarkOrange" 
         BorderThickness="3"
         CornerRadius="4" Margin="10" Background="White" 
         Template="{StaticResource FlipPanel_RotateHorizontalTemplate}" >
              <!-- Style="{StaticResource FlipPanel_RotateHorizontalStyle}" -->
      <flip:FlipPanel.FrontContent>
        <StackPanel Margin="6">
          <TextBlock TextWrapping="Wrap" Margin="3" FontSize="16" 
                   Foreground="DarkOrange"
                    >This is the front side of the FlipPanel.</TextBlock>
          <Button Margin="3" Padding="3" Content="Button One"></Button>
          <Button Margin="3" Padding="3" Content="Button Two"></Button>
          <Button Margin="3" Padding="3" Content="Button Three"></Button>
          <Button Margin="3" Padding="3" Content="Button Four"></Button>
        </StackPanel>
      </flip:FlipPanel.FrontContent>
      <flip:FlipPanel.BackContent>
        <Grid Margin="6">
          <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition></RowDefinition>
          </Grid.RowDefinitions>
          <TextBlock TextWrapping="Wrap" Margin="3" FontSize="16" 
                  Foreground="DarkMagenta"
                      >This is the back side of the FlipPanel.</TextBlock>
          <Button Grid.Row="2" Margin="3" Padding="10" 
                  Content="Flip Back to Front" HorizontalAlignment="Center" 
                  VerticalAlignment="Center" Click="cmdFlip2_Click"></Button>
        </Grid>
      </flip:FlipPanel.BackContent>
    </flip:FlipPanel>

    <flip:FlipPanel x:Name="panel3" Grid.Row="2" BorderBrush="DarkOrange" 
         BorderThickness="3"
         CornerRadius="4" Margin="10" Background="White" > 
                   <!-- using default style here -->
      <flip:FlipPanel.FrontContent>
        <StackPanel Margin="6">
          <TextBlock TextWrapping="Wrap" Margin="3" FontSize="16" 
                   Foreground="DarkOrange"
                    >This is the front side of the FlipPanel.</TextBlock>
          <Button Margin="3" Padding="3" Content="Button One"></Button>
          <Button Margin="3" Padding="3" Content="Button Two"></Button>
          <Button Margin="3" Padding="3" Content="Button Three"></Button>
          <Button Margin="3" Padding="3" Content="Button Four"></Button>
        </StackPanel>
      </flip:FlipPanel.FrontContent>
      <flip:FlipPanel.BackContent>
        <Grid Margin="6">
          <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition></RowDefinition>
          </Grid.RowDefinitions>
          <TextBlock TextWrapping="Wrap" Margin="3" FontSize="16" 
                  Foreground="DarkMagenta"
                      >This is the back side of the FlipPanel.</TextBlock>
          <Button Grid.Row="2" Margin="3" Padding="10" 
                  Content="Flip Back to Front" HorizontalAlignment="Center" 
                  VerticalAlignment="Center" Click="cmdFlip2_Click"></Button>
        </Grid>
      </flip:FlipPanel.BackContent>
    </flip:FlipPanel>




</Grid>
</UserControl>

 

Note that I decided to prefix names with "FlipPanel_", not sure if there’s some better way (using XAML namespaces somehow) to avoid any conflicts when merging the dictionaries and resolving the resouces with "{StaticResource …}"

Also note that in each theme file I also provide a Style (that sets the corresponding Template property of the FlipPanel conrol) that one can use instead of using the Template directly. At that Style more FlipPanel control properties could be set to values appropriate for that template (the template defines a skeleton and the style dresses the pirate [skeleton] as somebody cleverly pointed out).

Note that Generic.xaml merges and uses the templat from one of the themes. Couldmake copies of files similar to Generic.xaml and reference the same template but with different values in the Style for other properties to make variations without resorting to Copy/Paste when multiple Themes use the same Template but restyle it a bit.

Another important note is that at Generic.xaml you must not use x:Key="FlipPanel_DefaultStyle" or anyother key at the default style, or the command

        public FlipPanel()
        {
            DefaultStyleKey = typeof(FlipPanel);
        }

won’t load the default style (which is needed when you don’t provide a Template or Style value at the consumer XAML (FlipPanelTest.xaml). Probably one can modify it to load a style by name instead of just by type (probably the issue was that it found multiple named styles applying to that type [both FlipPanel_RotateHorizontalStyle and FlipPanel_DefaultStyle] in the Generic.xaml), but removing the Key and using an unnamed style seems to do the trick.

What to do if Generic.xaml doesn’t get loaded for WPF control

Just came across http://wangmo.wordpress.com/2007/09/27/themesgenericxaml/ which gave me a hint on why a WPF control wasn’t getting instantiated correctly when loaded from an external assembly (dll):

to load generic.xaml for WPF, at the start of Properties\AssemblyInfo.cs you need (note this isn’t used/needed in Silverlight):

using System.Windows;

and at the end of Properties\AssemblyInfo.cs you need:

[assembly: ThemeInfo(
ResourceDictionaryLocation.None, //where theme specific resource dictionaries are located
//(used if a resource is not found in the page,
// or application resource dictionaries)
ResourceDictionaryLocation.SourceAssembly //where the generic resource dictionary is located
//(used if a resource is not found in the page,
// app, or any theme specific resource dictionaries)
)]

Mind you that if the project doesn’t show a Properties node in Solution Explorer, you have to either make a new project using the correct template (for a WPF custom control), or right click the project, select Properties, then press the Assembly Information button and enter some dummy values, then OK to create the Properties node (which also creates to a Properties subfolder and AssemblyInfo.cs file).

You can expand (drop-down) the special Properties node in solution explorer then to open AssemblyInfo.cs and add the above stuff if missing.