public override ElementCompletionResult GetElementCompletions(ElementCompletionContext completionContext)
{
if (completionContext == null)
{
throw new ArgumentNullException(nameof(completionContext));
}
var elementCompletions = new Dictionary <string, HashSet <TagHelperDescriptor> >(StringComparer.OrdinalIgnoreCase);
AddAllowedChildrenCompletions(completionContext, elementCompletions);
if (elementCompletions.Count > 0)
{
// If the containing element is already a TagHelper and only allows certain children.
var emptyResult = ElementCompletionResult.Create(elementCompletions);
return(emptyResult);
}
elementCompletions = completionContext.ExistingCompletions.ToDictionary(
completion => completion,
_ => new HashSet <TagHelperDescriptor>(),
StringComparer.OrdinalIgnoreCase);
var catchAllDescriptors = new HashSet <TagHelperDescriptor>();
var prefix = completionContext.DocumentContext.Prefix ?? string.Empty;
var possibleChildDescriptors = _tagHelperFactsService.GetTagHelpersGivenParent(completionContext.DocumentContext, completionContext.ContainingTagName);
foreach (var possibleDescriptor in possibleChildDescriptors)
{
var addRuleCompletions = false;
var outputHint = possibleDescriptor.TagOutputHint;
foreach (var rule in possibleDescriptor.TagMatchingRules)
{
if (rule.TagName == TagHelperMatchingConventions.ElementCatchAllName)
{
catchAllDescriptors.Add(possibleDescriptor);
}
else if (elementCompletions.ContainsKey(rule.TagName))
{
addRuleCompletions = true;
}
else if (outputHint != null)
{
// If the current descriptor has an output hint we need to make sure it shows up only when its output hint would normally show up.
// Example: We have a MyTableTagHelper that has an output hint of "table" and a MyTrTagHelper that has an output hint of "tr".
// If we try typing in a situation like this: <body > | </body>
// We'd expect to only get "my-table" as a completion because the "body" tag doesn't allow "tr" tags.
addRuleCompletions = elementCompletions.ContainsKey(outputHint);
}
else if (!completionContext.InHTMLSchema(rule.TagName))
{
// If there is an unknown HTML schema tag that doesn't exist in the current completion we should add it. This happens for
// TagHelpers that target non-schema oriented tags.
addRuleCompletions = true;
}
if (addRuleCompletions)
{
UpdateCompletions(prefix + rule.TagName, possibleDescriptor);
}
}
}
// We needed to track all catch-alls and update their completions after all other completions have been completed.
// This way, any TagHelper added completions will also have catch-alls listed under their entries.
foreach (var catchAllDescriptor in catchAllDescriptors)
{
foreach (var completionTagName in elementCompletions.Keys)
{
if (elementCompletions[completionTagName].Count > 0 ||
!string.IsNullOrEmpty(prefix) && completionTagName.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
{
// The current completion either has other TagHelper's associated with it or is prefixed with a non-empty
// TagHelper prefix.
UpdateCompletions(completionTagName, catchAllDescriptor);
}
}
}
var result = ElementCompletionResult.Create(elementCompletions);
return(result);
void UpdateCompletions(string tagName, TagHelperDescriptor possibleDescriptor)
{
if (!elementCompletions.TryGetValue(tagName, out var existingRuleDescriptors))
{
existingRuleDescriptors = new HashSet <TagHelperDescriptor>();
elementCompletions[tagName] = existingRuleDescriptors;
}
existingRuleDescriptors.Add(possibleDescriptor);
}
}
public override ElementCompletionResult GetElementCompletions(ElementCompletionContext completionContext)
{
if (completionContext == null)
{
throw new ArgumentNullException(nameof(completionContext));
}
var elementCompletions = new Dictionary <string, HashSet <TagHelperDescriptor> >(StringComparer.OrdinalIgnoreCase);
AddAllowedChildrenCompletions(completionContext, elementCompletions);
if (elementCompletions.Count > 0)
{
// If the containing element is already a TagHelper and only allows certain children.
var emptyResult = ElementCompletionResult.Create(elementCompletions);
return(emptyResult);
}
elementCompletions = completionContext.ExistingCompletions.ToDictionary(
completion => completion,
_ => new HashSet <TagHelperDescriptor>(),
StringComparer.Ordinal);
var catchAllDescriptors = new HashSet <TagHelperDescriptor>();
var prefix = completionContext.DocumentContext.Prefix ?? string.Empty;
var possibleChildDescriptors = _tagHelperFactsService.GetTagHelpersGivenParent(completionContext.DocumentContext, completionContext.ContainingTagName);
possibleChildDescriptors = FilterFullyQualifiedCompletions(possibleChildDescriptors);
foreach (var possibleDescriptor in possibleChildDescriptors)
{
var addRuleCompletions = false;
var outputHint = possibleDescriptor.TagOutputHint;
foreach (var rule in possibleDescriptor.TagMatchingRules)
{
if (!TagHelperMatchingConventions.SatisfiesParentTag(completionContext.ContainingTagName, rule))
{
continue;
}
if (rule.TagName == TagHelperMatchingConventions.ElementCatchAllName)
{
catchAllDescriptors.Add(possibleDescriptor);
}
else if (elementCompletions.ContainsKey(rule.TagName))
{
addRuleCompletions = true;
}
else if (outputHint != null)
{
// If the current descriptor has an output hint we need to make sure it shows up only when its output hint would normally show up.
// Example: We have a MyTableTagHelper that has an output hint of "table" and a MyTrTagHelper that has an output hint of "tr".
// If we try typing in a situation like this: <body > | </body>
// We'd expect to only get "my-table" as a completion because the "body" tag doesn't allow "tr" tags.
addRuleCompletions = elementCompletions.ContainsKey(outputHint);
}
else if (!completionContext.InHTMLSchema(rule.TagName) || rule.TagName.Any(c => char.IsUpper(c)))
{
// If there is an unknown HTML schema tag that doesn't exist in the current completion we should add it. This happens for
// TagHelpers that target non-schema oriented tags.
// The second condition is a workaround for the fact that InHTMLSchema does a case insensitive comparison.
// We want completions to not dedupe by casing. E.g, we want to show both <div> and <DIV> completion items separately.
addRuleCompletions = true;
}
if (addRuleCompletions)
{
UpdateCompletions(prefix + rule.TagName, possibleDescriptor);
}
}
}
// We needed to track all catch-alls and update their completions after all other completions have been completed.
// This way, any TagHelper added completions will also have catch-alls listed under their entries.
foreach (var catchAllDescriptor in catchAllDescriptors)
{
foreach (var completionTagName in elementCompletions.Keys)
{
if (elementCompletions[completionTagName].Count > 0 ||
(!string.IsNullOrEmpty(prefix) && completionTagName.StartsWith(prefix, StringComparison.OrdinalIgnoreCase)))
{
// The current completion either has other TagHelper's associated with it or is prefixed with a non-empty
// TagHelper prefix.
UpdateCompletions(completionTagName, catchAllDescriptor);
}
}
}
var result = ElementCompletionResult.Create(elementCompletions);
return(result);
void UpdateCompletions(string tagName, TagHelperDescriptor possibleDescriptor)
{
if (possibleDescriptor.BoundAttributes.Any(boundAttribute => boundAttribute.IsDirectiveAttribute()))
{
// This is a TagHelper that ultimately represents a DirectiveAttribute. In classic Razor TagHelper land TagHelpers with bound attribute descriptors
// are valuable to show in the completion list to understand what was possible for a certain tag; however, with Blazor directive attributes stand
// on their own and shouldn't be indicated at the element level completion.
return;
}
if (!elementCompletions.TryGetValue(tagName, out var existingRuleDescriptors))
{
existingRuleDescriptors = new HashSet <TagHelperDescriptor>();
elementCompletions[tagName] = existingRuleDescriptors;
}
existingRuleDescriptors.Add(possibleDescriptor);
}
}