.NET MAUI PDF Viewer Custom Search
You can extend the search functionality by implementing a custom TextSearchWorker. The TextSearchWorker object performs the actual search according to the search criteria.
The example below implements a custom search by multiple words-any word that is entered into the input is considered as a separate search text.
1. Create a custom class that derives from Telerik.Maui.Controls.PdfViewer.PdfViewerTextSearchWorker-you need to override the Search method that returns TextSearchResult object:
public class MultipleWordsSearchWorker : Telerik.Maui.Controls.PdfViewer.PdfViewerTextSearchWorker
{
protected override PdfViewerTextSearchResult Search(PdfViewerSearchContext context)
{
string regex = GetMultiWordRegex(context.Text);
TextSearchOptions regexOptions = new TextSearchOptions { UseRegularExpression = true };
PdfViewerSearchContext newContext = new PdfViewerSearchContext(context.PdfViewer, context.Document, regex, regexOptions, context.SearchProgress, context.CancellationToken);
return base.Search(newContext);
}
private static string GetMultiWordRegex(string text)
{
string[] words = text.Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries);
StringBuilder sb = new StringBuilder();
for (int i = 0; i < words.Length; i++)
{
if (i > 0)
{
sb.Append("|");
}
string expr = string.Format(@"({0})", words[i]);
sb.Append(expr);
}
return sb.ToString();
}
}
2. Apply the MultipleWordsSearchWorker object to the TextSearchWorker property of the SearchSettings of RadPdfViewer:
<telerik:RadPdfViewer x:Name="pdfViewer">
<telerik:RadPdfViewer.SearchSettings>
<telerik:PdfViewerSearchSettings MainSearchResultFill="#99FF7F7F"
SearchResultsStringFormat="Result: {0}, Total: {2}"
SearchResultsFill="#997FC9FF"
TextSearchTrigger="TextChanged">
<telerik:PdfViewerSearchSettings.TextSearchWorker>
<local:MultipleWordsSearchWorker/>
</telerik:PdfViewerSearchSettings.TextSearchWorker>
</telerik:PdfViewerSearchSettings>
</telerik:RadPdfViewer.SearchSettings>
</telerik:RadPdfViewer >
3. Set the Source to the PDF viewer:
Func<CancellationToken, Task<Stream>> streamFunc = ct => Task.Run(() =>
{
Assembly assembly = typeof(SearchSettings).Assembly;
string fileName = assembly.GetManifestResourceNames().FirstOrDefault(n => n.Contains("pdf-processing.pdf"));
Stream stream = assembly.GetManifestResourceStream(fileName);
return stream;
});
this.pdfViewer.Source = streamFunc;
4. Add the telerik namespace:
xmlns:telerik="http://schemas.telerik.com/2022/xaml/maui"