/// <inheritdoc />
/// <remarks>
/// Does nothing if user provides an <c>action</c> attribute and <see cref="Antiforgery"/> is <c>null</c> or
/// <c>false</c>.
/// </remarks>
/// <exception cref="InvalidOperationException">
/// Thrown if <c>action</c> attribute is provided and <see cref="Action"/> or <see cref="Controller"/> are
/// non-<c>null</c> or if the user provided <c>asp-route-*</c> attributes.
/// </exception>
public override void Process(TagHelperContext context, TagHelperOutput output)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (output == null)
{
throw new ArgumentNullException(nameof(output));
}
if (Method != null)
{
output.CopyHtmlAttribute(nameof(Method), context);
}
var antiforgeryDefault = true;
// If "action" is already set, it means the user is attempting to use a normal <form>.
if (output.Attributes.ContainsName(HtmlActionAttributeName))
{
if (Action != null || Controller != null || Area != null || Route != null || RouteValues.Count != 0)
{
// User also specified bound attributes we cannot use.
throw new InvalidOperationException(
Resources.FormatFormTagHelper_CannotOverrideAction(
"<form>",
HtmlActionAttributeName,
ActionAttributeName,
ControllerAttributeName,
AreaAttributeName,
RouteAttributeName,
RouteValuesPrefix));
}
// User is using the FormTagHelper like a normal <form> tag. Antiforgery default should be false to
// not force the antiforgery token on the user.
antiforgeryDefault = false;
}
else
{
IDictionary<string, object> routeValues = null;
if (_routeValues != null && _routeValues.Count > 0)
{
// Convert from Dictionary<string, string> to Dictionary<string, object>.
routeValues = new Dictionary<string, object>(_routeValues.Count, StringComparer.OrdinalIgnoreCase);
foreach (var routeValue in _routeValues)
{
routeValues.Add(routeValue.Key, routeValue.Value);
}
}
if (Area != null)
{
if (routeValues == null)
{
routeValues = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
}
// Unconditionally replace any value from asp-route-area.
routeValues["area"] = Area;
}
TagBuilder tagBuilder;
if (Route == null)
{
tagBuilder = Generator.GenerateForm(
ViewContext,
Action,
Controller,
routeValues,
method: null,
htmlAttributes: null);
}
else if (Action != null || Controller != null)
{
// Route and Action or Controller were specified. Can't determine the action attribute.
throw new InvalidOperationException(
Resources.FormatFormTagHelper_CannotDetermineActionWithRouteAndActionOrControllerSpecified(
"<form>",
RouteAttributeName,
ActionAttributeName,
ControllerAttributeName,
HtmlActionAttributeName));
}
else
{
tagBuilder = Generator.GenerateRouteForm(
ViewContext,
Route,
routeValues,
method: null,
htmlAttributes: null);
}
if (tagBuilder != null)
{
output.MergeAttributes(tagBuilder);
output.PostContent.AppendHtml(tagBuilder.InnerHtml);
}
if (string.Equals(Method, FormMethod.Get.ToString(), StringComparison.OrdinalIgnoreCase))
{
antiforgeryDefault = false;
}
}
if (Antiforgery ?? antiforgeryDefault)
{
var antiforgeryTag = Generator.GenerateAntiforgery(ViewContext);
if (antiforgeryTag != null)
{
output.PostContent.AppendHtml(antiforgeryTag);
}
}
}
/// <inheritdoc />
public override void Process(TagHelperContext context, TagHelperOutput output)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (output == null)
{
throw new ArgumentNullException(nameof(output));
}
output.CopyHtmlAttribute(SrcAttributeName, context);
ProcessUrlAttribute(SrcAttributeName, output);
if (AppendVersion)
{
EnsureFileVersionProvider();
// Retrieve the TagHelperOutput variation of the "src" attribute in case other TagHelpers in the
// pipeline have touched the value. If the value is already encoded this ImageTagHelper may
// not function properly.
Src = output.Attributes[SrcAttributeName].Value as string;
output.Attributes.SetAttribute(SrcAttributeName, _fileVersionProvider.AddFileVersionToPath(Src));
}
}
/// <inheritdoc />
/// <remarks>
/// Does nothing unless <see cref="TagHelperContext.Items"/> contains a
/// <see cref="SelectTagHelper"/> <see cref="Type"/> entry and that entry is a non-<c>null</c>
/// <see cref="CurrentValues"/> instance. Also does nothing if the associated <option> is already
/// selected.
/// </remarks>
public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (output == null)
{
throw new ArgumentNullException(nameof(output));
}
// Pass through attributes that are also well-known HTML attributes.
if (Value != null)
{
output.CopyHtmlAttribute(nameof(Value), context);
}
// Nothing to do if this <option/> is already selected.
if (!output.Attributes.ContainsName("selected"))
{
// Is this <option/> element a child of a <select/> element the SelectTagHelper targeted?
object formDataEntry;
context.Items.TryGetValue(typeof(SelectTagHelper), out formDataEntry);
// ... And did the SelectTagHelper determine any selected values?
var currentValues = formDataEntry as CurrentValues;
if (currentValues?.Values != null && currentValues.Values.Count != 0)
{
// Select this <option/> element if value attribute or (if no value attribute) body matches a
// selected value. Body is encoded as-needed while executing child content. But TagHelperOutput
// itself encodes attribute values later, when start tag is generated.
bool selected;
if (Value != null)
{
selected = currentValues.Values.Contains(Value);
}
else
{
if (currentValues.ValuesAndEncodedValues == null)
{
// Include encoded versions of all selected values when comparing with body.
var allValues = new HashSet<string>(currentValues.Values, StringComparer.OrdinalIgnoreCase);
foreach (var selectedValue in currentValues.Values)
{
allValues.Add(Generator.Encode(selectedValue));
}
currentValues.ValuesAndEncodedValues = allValues;
}
TagHelperContent childContent;
if (output.IsContentModified)
{
// Another tag helper has modified the body. Use what they wrote.
childContent = output.Content;
}
else
{
childContent = await output.GetChildContentAsync();
}
selected = currentValues.ValuesAndEncodedValues.Contains(childContent.GetContent());
}
if (selected)
{
output.Attributes.Add("selected", "selected");
}
}
}
}
/// <inheritdoc />
public override void Process(TagHelperContext context, TagHelperOutput output)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (output == null)
{
throw new ArgumentNullException(nameof(output));
}
// Pass through attribute that is also a well-known HTML attribute.
if (Href != null)
{
output.CopyHtmlAttribute(HrefAttributeName, context);
}
// If there's no "href" attribute in output.Attributes this will noop.
ProcessUrlAttribute(HrefAttributeName, output);
// Retrieve the TagHelperOutput variation of the "href" attribute in case other TagHelpers in the
// pipeline have touched the value. If the value is already encoded this LinkTagHelper may
// not function properly.
Href = output.Attributes[HrefAttributeName]?.Value as string;
Mode mode;
if (!AttributeMatcher.TryDetermineMode(context, ModeDetails, Compare, out mode))
{
// No attributes matched so we have nothing to do
return;
}
if (AppendVersion == true)
{
EnsureFileVersionProvider();
if (Href != null)
{
var index = output.Attributes.IndexOfName(HrefAttributeName);
output.Attributes[index] = new TagHelperAttribute(
HrefAttributeName,
_fileVersionProvider.AddFileVersionToPath(Href));
}
}
var builder = new DefaultTagHelperContent();
if (mode == Mode.GlobbedHref || mode == Mode.Fallback && !string.IsNullOrEmpty(HrefInclude))
{
BuildGlobbedLinkTags(output.Attributes, builder);
if (string.IsNullOrEmpty(Href))
{
// Only HrefInclude is specified. Don't render the original tag.
output.TagName = null;
output.Content.SetHtmlContent(HtmlString.Empty);
}
}
if (mode == Mode.Fallback)
{
string resolvedUrl;
if (TryResolveUrl(FallbackHref, resolvedUrl: out resolvedUrl))
{
FallbackHref = resolvedUrl;
}
BuildFallbackBlock(builder);
}
output.PostElement.SetHtmlContent(builder);
}
/// <inheritdoc />
/// <remarks>Does nothing if <see cref="For"/> is <c>null</c>.</remarks>
/// <exception cref="InvalidOperationException">
/// Thrown if <see cref="Format"/> is non-<c>null</c> but <see cref="For"/> is <c>null</c>.
/// </exception>
public override void Process(TagHelperContext context, TagHelperOutput output)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (output == null)
{
throw new ArgumentNullException(nameof(output));
}
// Pass through attributes that are also well-known HTML attributes. Must be done prior to any copying
// from a TagBuilder.
if (InputTypeName != null)
{
output.CopyHtmlAttribute("type", context);
}
if (Value != null)
{
output.CopyHtmlAttribute(nameof(Value), context);
}
// Note null or empty For.Name is allowed because TemplateInfo.HtmlFieldPrefix may be sufficient.
// IHtmlGenerator will enforce name requirements.
var metadata = For.Metadata;
var modelExplorer = For.ModelExplorer;
if (metadata == null)
{
throw new InvalidOperationException(Resources.FormatTagHelpers_NoProvidedMetadata(
"<input>",
ForAttributeName,
nameof(IModelMetadataProvider),
For.Name));
}
string inputType;
string inputTypeHint;
if (string.IsNullOrEmpty(InputTypeName))
{
// Note GetInputType never returns null.
inputType = GetInputType(modelExplorer, out inputTypeHint);
}
else
{
inputType = InputTypeName.ToLowerInvariant();
inputTypeHint = null;
}
// inputType may be more specific than default the generator chooses below.
if (!output.Attributes.ContainsName("type"))
{
output.Attributes.SetAttribute("type", inputType);
}
TagBuilder tagBuilder;
switch (inputType)
{
case "checkbox":
GenerateCheckBox(modelExplorer, output);
return;
case "hidden":
tagBuilder = Generator.GenerateHidden(
ViewContext,
modelExplorer,
For.Name,
value: For.Model,
useViewData: false,
htmlAttributes: null);
break;
case "password":
tagBuilder = Generator.GeneratePassword(
ViewContext,
modelExplorer,
For.Name,
value: null,
htmlAttributes: null);
break;
case "radio":
tagBuilder = GenerateRadio(modelExplorer);
break;
default:
tagBuilder = GenerateTextBox(modelExplorer, inputTypeHint, inputType);
break;
}
if (tagBuilder != null)
{
// This TagBuilder contains the one <input/> element of interest. Since this is not the "checkbox"
// special-case, output is a self-closing element no longer guaranteed.
output.MergeAttributes(tagBuilder);
output.Content.AppendHtml(tagBuilder.InnerHtml);
}
}
