How to add data into RichTextBox from two datasourses in WPF

Question

I need to put data from two different datasourses in the same textbox. The text that comes from the first one have to be bolded and the secound normal.

It's there a possibility to do this in WPF?

Answer 1

Hi! You cannot bind (or multibind) to Document property of RichTextBox, because it is NOT a DependencyProperty (strange!!!)!!! See this link for a really easy way of subclassing RichTextBox to create your own BindableRichTextBox or this post for another workaround.

Now you can use MultiBinding with a custom IMultiValueConverter to achieve the results. Since you have not given much details of your problem, I can only give you an overall idea of what you should do:

<!--NOTE: Include xmlns:local=" .. " appropriately for your project-->
<Window.Resources>
    <sys:String x:Key="SourceA">This text will be normal..</sys:String>
    <sys:String x:Key="SourceB">This text will be Bold!!!</sys:String>
</Window.Resources>

And now you can do like this:

<local:BindableRichTextBox>
    <!--<local:BindableRichTextBox.Document>-->
        <MultiBinding Converter="{x:Static local:MySourceBToBoldConverter.Instance}">
            <Binding Source="{StaticResource SourceA}" />
            <Binding Source="{StaticResource SourceB}" />
        </MultiBinding>
    <!--</local:BindableRichTextBox.Document>-->
</local:BindableRichTextBox>

And then create a class MySourceBToBoldConverter that inherits from IMultiValueConverter like this:

public class MySourceBToBoldConverter : IMultiValueConverter
{
    public static readonly MySourceBToBoldConverter Instance = new MySourceBToBoldConverter();

    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        //Now you'll get value from Source A as value[0]
        //           and value from Source B as value[1]
        //Do whatever you want like bold etc...
        //and return the result

        string normalText = values[0] as string;
        string boldText = values[1] as string;

        Bold bold = new Bold();
        bold.Inlines.Add(boldText);

        Paragraph para = new Paragraph();
        para.Inlines.Add(normalText);
        para.Inlines.Add(bold);

        FlowDocument rtbDocument = new FlowDocument();
        rtbDocument.Blocks.Add(para);

        return rtbDocument;
    }

    public object[] ConvertBack(object value, ... )
    {
        //Convert the object returned by Convert() back 
        //to its original form if it's possible;
        //otherwise throw not supported exception ;)

        throw new NotImplementedException();
    }
}

Currently I don't have my work PC with me that has VS installed, so I can't give you a working example, but go ahead and search google/msdn/stackoverflow 4 MultiBinding and IMultiValueConverter and you'll find some good examples out there.

Check the working example here.

Regards,
Mihir Gokani