public void DeleteText(int start, int end)
{
if (maskedTextBox.ReadOnly)
{
throw new ElementNotEnabledException();
}
if (Provider.Control.InvokeRequired)
{
Provider.Control.BeginInvoke(new DeleteTextDelegate(DeleteText),
new object [] { start, end });
return;
}
// MaskedTextProvider.RemoveAt does not work for this.
System.ComponentModel.MaskedTextProvider prov
= maskedTextBox.MaskedTextProvider;
string text = prov.ToDisplayString();
for (int i = start; i < end; i++)
{
if (!prov.IsEditPosition(i) ||
prov.IsAvailablePosition(i))
{
continue;
}
text = text.Substring(0, i) + prov.PromptChar
+ text.Substring(i + 1);
}
maskedTextBox.Text = text;
}
// This is kind of crack. Basically, in order to emulate what
// happens in the GUI, InsertText will actually overwrite
// characters in the DisplayString as long as they're
// placeholders. If we just inserted as usual, it would be
// rejected as it contains too many characters.
public void InsertText(string str, ref int position)
{
if (maskedTextBox.ReadOnly)
{
throw new ElementNotEnabledException();
}
if (Provider.Control.InvokeRequired)
{
object[] args = new object[] { str, position };
Provider.Control.BeginInvoke(new InsertTextDelegate(InsertText), args);
position = (int)args[1];
return;
}
System.ComponentModel.MaskedTextProvider prov
= maskedTextBox.MaskedTextProvider;
string text = prov.ToDisplayString();
int offset = position;
for (int i = 0; i < str.Length; i++)
{
int localOffset = offset;
// skip over an unavailable slot if we see one
bool reachedBounds = false;
while (!prov.IsEditPosition(i + localOffset))
{
localOffset++;
if (i + localOffset >= prov.Length)
{
reachedBounds = true;
break;
}
}
if (reachedBounds)
{
break;
}
// There is already a character here, so while
// the GUI will actually move this character
// over, we cannot as there are _many, many_
// edge cases that we cannot handle.
// Instead, we skip over the character.
if (!prov.IsAvailablePosition(i + localOffset))
{
// Make sure offset is correct for the
// next iteration
offset = localOffset;
continue;
}
// The correct value of position is equal to
// the localOffset of the first character.
//
// This check needs to be done after
// IsAvailablePosition in case we are trying to
// insert into a place that already has a
// character.
if (offset != localOffset && i == 0)
{
position = localOffset;
}
offset = localOffset;
text = text.Substring(0, i + offset)
+ str[i] + text.Substring(i + offset + 1);
}
maskedTextBox.Text = text;
}