I am about to build a block for creating content tables in Episerver.
I would like this block to have a ContentArea which in turn will contain only blocks of type TableRowBlock (so that I can have an arbitrary number of rows).
If I create a block type called TableBlock and another one called TableRowBlock, they will both be visible when an editor adds a new block.
Since TableRowBlock only makes sense within a TableBlock, I would like to hide it so that it is only visible when adding a block to the ContentArea property of a TableBlock.
How can I do this?
What you're asking isn't supported out-of-the-box, I'm afraid.
However, you could:
Add an [AllowedContentTypes] attribute to your ContentArea property for TableBlock, and specify the TableRowBlock type as the allowed type. That way the editor won't have to select block type when clicking "Add new block" in the content area editor.
Customize which content type(s) are suggested when new content is created by creating your own IContentTypeAdvisor which would suggest TableRowBlock when TableBlock is being edited:
[ServiceConfiguration(typeof(IContentTypeAdvisor))]
public class ContentTypeAdvisor : IContentTypeAdvisor
{
public IEnumerable<int> GetSuggestions(IContent parent, bool contentFolder, IEnumerable<string> requestedTypes)
{
// Suggest relevant content types
}
}
Full example available here.
Related
I have a content area in a page .This content area holds different other blocks as part of content area items.
For instance, News Page has content area. Content area has Carousal block, Hero Block ,XYZ block & so on.
Is there a way to get all the properties of XHTMLstring type from all the blocks(carousal, hero ,xyz).I need to get all the text from these blocks.
If the blocks within the content area all implement a interface that exposes a xhtmlstring, for example IContentWithXhtmlString, then you should be able to access it with something like this.
var repo = ServiceLocator.Current.GetInstance<IContentRepository>();
var contentItems = currentPage.MyContentAreaProperty
.FilteredItems
.Select(x => repo.Get<IContentWithXhtmlString>(x.XhtmlString));
Further reading can be found here
This question is an offshoot of: Localizing ObjectListView OLVColumn, impossible due to Empty Name property
For simplicity's sake, let's say my ObjectListView contains car information. User A wants to display only Make and Model columns. User B only wants to display Model and Year columns. These preferences would be saved to/loaded from an .ini file on the users' local machines.
I cannot loop through the columns of the ObjectListView and do if (col.Name == colNameFromIni) { col.Visible == true; } because the .Name property of every column is an empty string ("") and does not get serialized to the designer codebehind file. This never happens with any other Winforms control (Label, Button, etc.) They always get their .Name written to the designer codebehind.
In some sense, this is a flaw in Winforms itself, because OLVColumn inherits from System.Windows.Forms.ColumnHeader, and a traditional ListView has exactly the same problem. .Name is always an empty string for all columns.
I would like to patch our local build of ObjectListView.dll to force populate the .Name property, but I can't figure out how Winforms automagically knows the name of every control on the form. It somehow(?) knows the names of the OLVColumn objects since it can display them in the Edit Columns... dialog on the ObjectListView's context menu. I'm also a little fuzzy on where the best spot is to plug this in.
(Yes, per linked question at top I know that as a last resort, I can hardcode colXX.Name = "colXX"; for all columns in my source code, but future column additions are likely to get overlooked and a programmatic solution is much preferred.)
(See also: https://sourceforge.net/p/objectlistview/bugs/160/ : the ObjectListView author declared this a wont-fix so it is up to me (or us), I guess.)
As you point out, this is a bug which is not with the ObjectListView, but the underlying component. And a bug which is around since at least 2008! Therefore, I doubt it will ever be fixed by MS.
Actually, it is a problem with the Autogenerated code in the designer.
If you look at other components such as a button, then the autogenerated code adds a name such as this;
//
// button2
//
this.button2.Location = new System.Drawing.Point(458, 199);
this.button2.Name = "button2";
...
But for ColumnHeader (Listview) and OLVColumn (ObjectListView), then this is not done, so then you end up with this.
//
// olvColumn1
//
this.olvColumn1.AspectName = "Name";
this.olvColumn1.Text = "Name";
If you manually add the line
this.olvColumn1.Text = "olvColumn1";
Then the "problem" is solved.
Of course, you can't do this, because the designer will override the autogenerated code when you make any changes, and then you will lose these manually added lines. It is also not sustainable.
So I'm afraid you need to code around this with some kind of ugly solution. Some options are:
Use the Tag to store the name and compare against this.
Use the text instead of the name (not possible if you have multi
language support!)
Code the names column manually in the Constructor
Set the Text to be something like "ColName;ColText" and then in your
code separate these out.
I have done option 3 in the past, but only I was maintaining the code, so this was easy.
What you could do to ensure you don't have discrepancies is to add a check in your constructor to compare the actual number of columns with the number you expect (hard coded for), and throw an exception if they don't match. Also, not the best, but another way to highlight and reduce errors.
The workaround for this is to get the OLVColumns via reflection and set their column's Name property at runtime. Every OLVColumn is a form-level field, so just pick them out of the list returned by GetFields().
Dim allFieldInfos As FieldInfo() = GetType(FrmMain).GetFields(BindingFlags.NonPublic or BindingFlags.Instance)
For Each fi As FieldInfo In allFieldInfos
If fi.FieldType Is GetType(OLVColumn) Then
Dim instance As OLVColumn = fi.GetValue(Me)
For Each col As OLVColumn In fdlvMain.AllColumns
If ReferenceEquals(col, instance) Then
col.Name = fi.Name
End If
Next
End If
Next
I want to add movieclips which are instances of a certain class to an array (only add movie clips which are instances of BLAH). I can't find any property which refers to the movieclip's class. Can anyone help?
Use is operator:
if( mc is BLAH){
// here you are
}
From docs:
Evaluates whether an object is compatible with a specific data type,
class, or interface
I'm trying to create a WPF MarkupExtension class that provides translated text from my text translation class. The translation stuff works great, but requires a static method call with a text key to return the translated text. Like this:
ImportLabel.Text = Translator.Translate("import files");
// will be "Dateien importieren" in de or "Import files" in en
Its speciality is that it accepts a counting value to provide better wordings.
ImportLabel.Text = Translator.Translate("import n files", FileCount);
// will be "Import 7 files" or "Import 1 file"
Another example: If something takes yet 4 minutes, it's a different word than if it only takes one minute. If a text key "minutes" is defined as "Minuten" for any number and as "Minute" for a count of 1, the following method call will return the right word to use:
Translator.Translate("minutes", numberOfMinutes)
// will be "minute" if it's 1, and "minutes" for anything else
Now in a WPF application, there's a lot of XAML code and that contains lots of literal texts. To be able to translate them without getting nuts, I need a markup extension which I can pass my text key and that will return the translated text at runtime. This part is fairly easy. Create a class inheriting from MarkupExtension, add a constructor that accepts the text key as argument, store it in a private field, and let its ProvideValue method return a translation text for the stored key.
My real problem is this: How can I make my markup extension accept a counting value in such a way that it's data-bound and the translation text will update accordingly when the count value changes?
It should be used like this:
<TextBlock Text="{t:Translate 'import files', {Binding FileCount}}"/>
Whenever the binding value of FileCount changes, the TextBlock must receive a new text value to reflect the change and still provide a good wording.
I've found a similar-looking solution over there: http://blogs.microsoft.co.il/blogs/tomershamam/archive/2007/10/30/wpf-localization-on-the-fly-language-selection.aspx But as hard as I try to follow it, I can't understand what it does or why it even works. Everything seems to happen inside of WPF, the provided code only pushes it in the right direction but it's unclear how. I can't get my adaption of it to do anything useful.
I'm not sure whether it could be useful to let the translation language change at runtime. I think I'd need another level of bindings for that. To keep complexity low, I would not seek to do that until the basic version works.
At the moment there's no code I could show you. It's simply in a terrible state and the only thing it does is throwing exceptions, or not translating anything. Any simple examples are very welcome (if such thing exists in this case).
Nevermind, I finally found out how the referenced code works and could come up with a solution. Here's just a short explanation for the record.
<TextBlock Text="{t:Translate 'import files', {Binding FileCount}}"/>
This requires a class TranslateExtension, inherited from MarkupExtension, with a constructor accepting two parameters, one String and one Binding. Store both values in the instance. The classes' ProvideValue method then uses the binding it gets, adds a custom converter instance to it and returns the result from binding.ProvideValue, which is a BindingExpression instance IIRC.
public class TranslateExtension : MarkupExtension
{
public TranslateExtension(string key, Binding countBinding)
{
// Save arguments to properties
}
public override object ProvideValue(IServiceProvider serviceProvider)
{
countBinding.Converter = new TranslateConverter(key);
return countBinding.ProvideValue(serviceProvider);
}
}
The converter, say of class TranslateConverter, has a constructor that accepts one parameter, a String. This is my key argument from the TranslateExtension above. It remembers it for later.
Whenever the Count value changes (it comes through the binding), WPF will request its value anew. It seems to walk from the source of the binding, through the converter, to the surface where it's displayed. By using a converter, we don't have to worry about the binding at all, because the converter gets the binding's current value as a method argument and is expected to return something else. Counting value (int) in, translated text (string) out. This is my code.
So it's the converter's task to adapt the number to a formulated text. It uses the stored text key for that. So what happens is basically a kinda backwards data flow. Instead of the text key being the main information and the count value being added to it, we need to treat the count value as the primary information and just use the text key as a side parameter to make it whole. This isn't exactly straightforward, but the binding needs to be the primary trigger. Since the key won't change, it can be stored for good in the instance of the converter. And every occurence of a translated text gets its own copy of the converter, each with an individual key programmed in.
This is what the converter could look like:
class TranslateConverter : IValueConverter
{
private string key;
public TranslateConverter(string key)
{
this.key = key;
}
public object Convert(object value, ...)
{
return Translator.Translate(key, (int) value);
}
}
That's the magic. Add the error handling and more features to get the solution.
I am attempting to set the Name property of a Page in the constructor:
public partial class PageListView : Page
{
public PageListView(string title)
{
InitializeComponent();
Name = title;
}
}
However, I often get the following error message.
'x' is not a valid value for property 'Name'.
Where x seems to be almost anything, drilling down into the exception details doesn't seem to provide any useful information (e.g. the InnerException is null.)
Does anyone know what is happening here?
The Name property generally follows the rules of C#/VB.NET identifiers (i.e. fields). Based on the documentation:
The string values used for Name have some restrictions, as imposed by
the underlying x:Name Directive defined by the XAML specification.
Most notably, a Name must start with a letter or the underscore character
(_), and must contain only letters, digits, or underscores.
Based on the parameter you are passing (i.e. title), it seems like you may violate that. But you'd have to give some specific examples to be sure.
Of course, moments after posting this I realised what's going on.
Because FrameworkElement.Name is used for creating object references, you have to ensure that the string contains only valid chars for an object instance variable name.
Use Title or another plain text property instead, unless you really want to set the x:Name property for referencing.