wertTextBox.DataBindings[0].BindingComplete += new BindingCompleteEventHandler(wertTextBox_BindingComplete);
Der Event-Handler kann dann folgendemaßen aussehen:
private void wertTextBox_BindingComplete(object sender, BindingCompleteEventArgs e)
{
if (e.BindingCompleteState != BindingCompleteState.Success)
{
errorProvider1.SetError(wertTextBox, e.ErrorText);
}
else
{
errorProvider1.SetError(wertTextBox, null);
}
}