private string GetUnambiguousPrefix(System.Collections.ObjectModel.Collection <CompletionResult> matches, out bool ambiguous)
{
// Find the longest unambiguous prefix. This might be the empty
// string, in which case we don't want to remove any of the users input,
// instead we'll immediately show possible completions.
// For the purposes of unambiguous prefix, we'll ignore quotes if
// some completions aren't quoted.
ambiguous = false;
var firstResult = matches[0];
bool consistentQuoting = IsConsistentQuoting(matches);
var replacementText = GetUnquotedText(firstResult, consistentQuoting);
foreach (var match in matches.Skip(1))
{
var matchText = GetUnquotedText(match, consistentQuoting);
for (int i = 0; i < replacementText.Length; i++)
{
if (i == matchText.Length ||
char.ToLowerInvariant(replacementText[i]) != char.ToLowerInvariant(matchText[i]))
{
ambiguous = true;
replacementText = replacementText.Substring(0, i);
break;
}
}
if (replacementText.Length == 0)
{
break;
}
}
if (replacementText.Length == 0)
{
replacementText = firstResult.ListItemText;
foreach (var match in matches.Skip(1))
{
var matchText = match.ListItemText;
for (int i = 0; i < replacementText.Length; i++)
{
if (i == matchText.Length ||
char.ToLowerInvariant(replacementText[i]) != char.ToLowerInvariant(matchText[i]))
{
ambiguous = true;
replacementText = replacementText.Substring(0, i);
break;
}
}
if (replacementText.Length == 0)
{
break;
}
}
}
return(replacementText);
}