public override SignatureHelpState GetCurrentArgumentState(SyntaxNode root, int position, ISyntaxFactsService syntaxFacts, TextSpan currentSpan, CancellationToken cancellationToken)
{
if (TryGetAttributeExpression(root, position, syntaxFacts, SignatureHelpTriggerReason.InvokeSignatureHelpCommand, cancellationToken, out var expression) &&
currentSpan.Start == SignatureHelpUtilities.GetSignatureHelpSpan(expression.ArgumentList).Start)
{
return(SignatureHelpUtilities.GetSignatureHelpState(expression.ArgumentList, position));
}
return(null);
}
public override SignatureHelpState GetCurrentArgumentState(SyntaxNode root, int position, ISyntaxFactsService syntaxFacts, TextSpan currentSpan, CancellationToken cancellationToken)
{
if (!TryGetElementAccessExpression(
root,
position,
syntaxFacts,
SignatureHelpTriggerReason.InvokeSignatureHelpCommand,
cancellationToken,
out var expression,
out var openBracket) ||
currentSpan.Start != expression.SpanStart)
{
return(null);
}
// If the user is actively typing, it's likely that we're in a broken state and the
// syntax tree will be incorrect. Because of this we need to synthesize a new
// bracketed argument list so we can correctly map the cursor to the current argument
// and then we need to account for this and offset the position check accordingly.
int offset;
BracketedArgumentListSyntax argumentList;
var newBracketedArgumentList = SyntaxFactory.ParseBracketedArgumentList(openBracket.Parent.ToString());
if (expression.Parent is ConditionalAccessExpressionSyntax)
{
// The typed code looks like: <expression>?[
var conditional = (ConditionalAccessExpressionSyntax)expression.Parent;
var elementBinding = SyntaxFactory.ElementBindingExpression(newBracketedArgumentList);
var conditionalAccessExpression = SyntaxFactory.ConditionalAccessExpression(expression, elementBinding);
offset = expression.SpanStart - conditionalAccessExpression.SpanStart;
argumentList = ((ElementBindingExpressionSyntax)conditionalAccessExpression.WhenNotNull).ArgumentList;
}
else
{
// The typed code looks like:
// <expression>[
// or
// <identifier>?[
ElementAccessExpressionSyntax elementAccessExpression = SyntaxFactory.ElementAccessExpression(expression, newBracketedArgumentList);
offset = expression.SpanStart - elementAccessExpression.SpanStart;
argumentList = elementAccessExpression.ArgumentList;
}
position -= offset;
return(SignatureHelpUtilities.GetSignatureHelpState(argumentList, position));
}
public override SignatureHelpState GetCurrentArgumentState(SyntaxNode root, int position, ISyntaxFactsService syntaxFacts, TextSpan currentSpan, CancellationToken cancellationToken)
{
if (!TryGetGenericIdentifier(root, position, syntaxFacts, SignatureHelpTriggerReason.InvokeSignatureHelpCommand, cancellationToken,
out var genericIdentifier, out var lessThanToken))
{
return(null);
}
if (genericIdentifier.TryParseGenericName(cancellationToken, out var genericName))
{
// Because we synthesized the generic name, it will have an index starting at 0
// instead of at the actual position it's at in the text. Because of this, we need to
// offset the position we are checking accordingly.
var offset = genericIdentifier.SpanStart - genericName.SpanStart;
position -= offset;
return(SignatureHelpUtilities.GetSignatureHelpState(genericName.TypeArgumentList, position));
}
return(null);
}