How to bind mutiple values to one label?

Question

I have implemented the IMultiValueConverter from Link to bind multiple values to one label.

namespace MyApp
{
[ValueConversion(typeof(object), typeof(string))]
public class ConcatenateFieldsMultiValueConverter : IMultiValueConverter
{
  public object Convert(
           object[] values,
           Type targetType,
           object parameter,
           System.Globalization.CultureInfo culture
        )
{
  string strDelimiter;
  StringBuilder sb = new StringBuilder();

  if (parameter != null)
  {
     //Use the passed delimiter.
     strDelimiter = parameter.ToString();
  }
  else
  {
     //Use the default delimiter.
     strDelimiter = ", ";
  }

  //Concatenate all fields
  foreach (object value in values)
  {
     if (value != null && value.ToString().Trim().Length > 0)
     {
        if (sb.Length > 0) sb.Append(strDelimiter);
        sb.Append(value.ToString());
     }
  }

  return sb.ToString();
}

public object[] ConvertBack(
           object value,
           Type[] targetTypes,
           object parameter,
           System.Globalization.CultureInfo culture
     )
{
  throw new NotImplementedException("ConcatenateFieldsMultiValueConverter cannot convert back (bug)!");
}
}
}

However when I am referencing

xmlns:local="clr-namespace:MyApp"

in my Window Properties in XAML (namespace MyApp) and define the following within in Window

<Window.Resources>
  <local:ConcatenateFieldsMultiValueConverter x:Key="mvc"/>
</Window.Resources>

my seperate class ConcatenateFieldsMultiValueConverter is not recognized.

Could you imagine why this class cannot be identified in the Window.Resources?

Answer 1

If you can use TextBlock, it can be done without any converter in place with only XAML.

<TextBlock>
    <TextBlock.Text>
        <MultiBinding StringFormat="{}{0}, {1}">
            <Binding Path="Property1"/>
            <Binding Path="Property2"/>
        </MultiBinding>
    </TextBlock.Text>
</TextBlock>

But it won't work for Label because, it uses Content property and not Text. Hence StringFormat can't be applied.

---

For Label you have to use IMultiValueConverter. Like mentioned in comments try re-compiling your project because posted code seems fine.

Answer 2

Compile it first, it looks like you are just getting design time error. I tried reproducing your problem and when I recompiled it went away.

It also runs in run time.