WinForms SpeechToTextButton Events

Updated on Feb 10, 2026

The RadSpeechToTextButton emits a set of events that allow you to configure the component's behavior in response to speech recognition.

The RadSpeechToTextButton exposes the following events:

• SpeechRecognized—Raised when the speech recognition is successful and the recognized text is available. The SpeechRecognized event handler receives two parameters:

  • The sender argument which is of type object but can be cast to RadSpeechToTextButton.
  • A SpeechRecognizerSpeechRecognizedEventArgs argument which has a reference to the:
    • FullText (string) property that contains the current full text recognized from the speech input from the beginning of the current listening session.
    • FullTextConfidenceScore property that indicates the confidence level of the recognition. The value is between 0 and 1, indicating how confident the speech-to-text transcription is. If the value is -1, a confidence score could not be provided.

• ErrorOccurred—Raised when an error occurs during the speech recognition process. The ErrorOccurred event handler receives two parameters:

  • The sender argument which is of type object but can be cast to RadSpeechToTextButton.
  • A SpeechRecognizerErrorOccurredEventArgs argument which has a reference to the:
    • Message (string) property that contains the error message describing the issue that occurred during speech recognition.
    • Exception (System.Exception) property that contains the exception associated with the speech recognizer error, if any.
    • Handled (bool) property that determines whether the error has been handled. Set this to true to prevent the default error handling behavior.

• StateChanged—Raised when the state of the speech recognizer changes. The StateChanged event handler receives two parameters:

  • The sender argument which is of type object but can be cast to RadSpeechToTextButton.
  • An System.EventArgs

• CalloutOpening—Occurs before the callout tooltip is opened, allowing customization or cancellation.

  • The sender argument which is of type object but can be cast to RadSpeechToTextButton.
  • A SpeechToTextTooltipOpeningEventArgs argument which has a reference to the:
    • State (SpeechRecognizerState) property that indicates the current state of the speech recognizer (e.g., Ready, Listening).
    • Callout (RadCallout) property that provides access to the callout tooltip control, allowing you to customize its appearance and behavior.
    • ToolTipText (string) property that gets or sets the text displayed in the tooltip. Modify this property to customize the tooltip message.
    • Cancel (bool) property that determines whether the tooltip opening should be cancelled. Set this to true to prevent the tooltip from being displayed.

Examle: Handling Speech Recognition Errors

To handle errors related to the speech recognition service, use the ErrorOccurred event. The SpeechRecognizerErrorOccurredEventArgs provide information about the error message via the Message and Exception properties.

Using ErrorOccurred event handler

C#

private void radSpeechToTextButton1_ErrorOccurred(object sender, SpeechRecognizerErrorOccurredEventArgs e)
{
    e.Handled = true;
    string errorMessage = e.Message;
    Exception exception = e.Exception;
    RadMessageBox.Show("Error: " + errorMessage, "Speech Recognition Error", MessageBoxButtons.OK, RadMessageIcon.Error);
}

VB.NET

Private Sub radSpeechToTextButton1_ErrorOccurred(sender As Object, e As SpeechRecognizerErrorOccurredEventArgs)
    e.Handled = True
    Dim errorMessage As String = e.Message
    Dim exception As Exception = e.Exception
    RadMessageBox.Show("Error: " + errorMessage, "Speech Recognition Error", MessageBoxButtons.OK, RadMessageIcon.Error)
End Sub