Some string-based HTML helpers can't get `Model` values if called from templates

[dougbu]

@Html.Checkbox(), @Html.Hidden(), and @Html.TextBox() do not behave as expected in template views. They resolve values using the full expression names (which won't find properties of the inner model), unlike all other HTML helpers. This leads to unexpectedly empty values in the generated HTML.

[rynowak]

Is this a change from MVC 5?

Can you include an example and what the expected behavior should be?

[dougbu]

MVC 5.2 has the same issue. This likely indicates templates aren't often used with string-based helpers.

Ex. Index.cshtml contains:

@Html.DisplayFor(model => model.Dependent, templateName: "Dependent")

DisplayTemplates/Dependent.cshtml contains:

<td>
    @Html.Label(expression: "Name", labelText: null, htmlAttributes: new { @class = "control-label", })
</td>
<td>
    '@Html.Value(name: "Name")'
</td>
<td>
    @Html.TextBox(name: "Name", value: null, htmlAttributes: new { disabled = "disabled", @readonly = "readonly", })
</td>

Result is:

More details:
Workaround is to use expression-based equivalents of these helpers (@Html.CheckBoxFor() etc.) or tag helpers.

Fix is to change lines 810 and 834 of DefaultHtmlGenerator to pass name and not fullName.

[dougbu]

... and the textbox should also contain "Dependents name" in the generated page.