private static void OnPasteForDouble(object sender, DataObjectPastingEventArgs e)
{
var textBox = (TextBox)sender;
var isText = e.SourceDataObject.GetDataPresent(DataFormats.Text, true);
if (!isText)
{
return;
}
// Getting data from clipboard
var clipboardText = (string)e.SourceDataObject.GetData(DataFormats.Text);
// Lets create full text box text by current text box state and text from clipboard
string text = CreateFullText(textBox, clipboardText);
bool isValid = TextBoxDoubleValidator.IsValid(text);
// If text is invalid we should cancel current command
if (!isValid)
{
e.CancelCommand();
}
}
private static void PreviewTextInputForDouble(object sender, TextCompositionEventArgs e)
{
var textBox = (TextBox)sender;
// Unforortunately TextBox doesn't provide PreviewTextChanged event where we can get
// full string that will be send to TextChanged event.
// PreviewTextInput contains only new input in e.Text property.
// But in some cases for validation we need full text but not only
// new input, in this case we should create full text by hand.
// Full text contains TextBox.Text WITHOUT selected text with e.Text
string fullText = CreateFullText(textBox, e.Text);
// Now fullText contains TextBox.Text that we'll have in TextChanged event
bool isTextValid = TextBoxDoubleValidator.IsValid(fullText);
// We'll stop text changed event if text is not a valid double
e.Handled = !isTextValid;
}