TLDR;
It is like the string/textbox binding works just fine on input controls, but the checkbox binding backed by Boolean properties does not work. I know the binding for checkbox values needs to used a 'checked' attribute instead of a 'value' attribute, but Blazor is supposed to handle that across different control types.
I'm doing some Blazor work (server-side app) with RC1 and cannot seem to get Boolean values binding to an input checkbox control. I believe that the syntax being used is correct (see below). As a simple test, I created a new project and simply replaced the index.razor page with the sample code below. When you run it, notice:
The "Test Value" for the textbox input control initializes just fine.
The checkbox's initial value is true, but the checkbox is not checked.
Change the textbox input control's text and then change control
focus. Notice a message gets printed in the Debug window in the Output
tab of Visual Studio (Expected behavior)
Change the checkbox input control's value (checking or uncheck) and then change control focus. Notice that there no message appears in the Debug window in the Output tab of Visual Studio (Not expected behavior).
#page "/"
<div class="form-group">
<label for="last-name">Textbox Binding Test</label>
<input #bind="TestString" type="text" class="form-control" id="last-name" placeholder="Enter Last Name" />
</div>
<div class="form-group">
<label for="send-email-updates">Checkbox Binding Test</label>
<input type="checkbox" bind="#TestBool" id="send-email-updates" />
</div>
#code {
private bool _testBool = true;
protected bool TestBool
{
get { return _testBool; }
set
{
_testBool = value;
System.Diagnostics.Debug.WriteLine($"Value of {nameof(TestBool)} = {value}");
}
}
private string _testString = "Test Value";
protected string TestString
{
get { return _testString; }
set
{
_testString = value;
System.Diagnostics.Debug.WriteLine($"Value of {nameof(TestString)} = {value}");
}
}
}
This behavior was observed regardless of making the properties public, used auto-properties (no private variables), or removed the control name/id attribute values. This seems to happen regardless of whether I use the #code directive on the page or separate out a viewmodel that inherits from ComponentBase.
The bottom line is that I'm able to get text-based values when a user submits the form, but all the Boolean properties seem to remain as they were when first initialized.
When you look at both controls:
<input #bind="TestString" type="text" class="form-control" id="last-name" placeholder="Enter Last Name" />
<input bind="#TestBool" type="checkbox" id="send-email-updates" />
It is clear you are mixing bind and #bind notations, probably from older Blazor editions.
This one works in rc1:
<input type="checkbox" #bind="TestBool" id="send-email-updates" />
but in general I would argue for using the <EditForm> and related tags:
<EditForm Model="this">
<InputCheckbox #bind-Value="TestBool" />
</EditForm>
Related
[See updates at bottom]
I have a Razor page with a form on it. I want to have two buttons on that form, that perform a slightly different action - both using the same posted form data.
I tried using the asp-page-handler helper on the second button, but it doesn't seem to add anything to the HTML (I would expect it to add a formaction attribute to the <button> element, but it doesn't add anything at all).
Here's an example page:
#page "{id?}"
#model IndexModel
#tagHelperPrefix x:
#addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
<p>Current value is #Model.Foo</p>
<x:form method="post">
<input type="text" name="foo" />
<button type="submit">Default</button>
<button type="submit" x:asp-page-handler="Alternative">Alternative</button>
</x:form>
... and here's the corresponding page model:
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
namespace MyWebApplication.Pages
{
public class IndexModel : PageModel
{
[BindProperty]
public string Foo { get; set; }
public void OnGet(int? id)
{
}
public void OnPostAsync(string foo)
{
Foo = foo;
}
public void OnPostAlternativeAsync(string foo)
{
Foo = foo.ToUpper();
}
}
}
This is rendered as:
...where the generated HTML for the form is:
<form method="post">
<input type="text" name="foo" />
<button type="submit">Default</button>
<button type="submit" x:asp-page-handler="Alternative">Alternative</button>
</form>
The fact that the x:asp-page-handler attribute is still in the generated HTML makes me think that the Razor engine hasn't recognized it. I've tried taking off the x: prefix, but that didn't help.
What am I doing wrong?
UPDATE
OK, I tried removing the tag prefix and removing the #tagHelperPrefix line, and that made a difference. A formaction is added to the second <button> element as expected.
However:
that's really annoying - the #tagHelperPrefix is not something I want to lose, and
now both buttons are triggering the "Alternative" action, even though only one of them has the formaction!
Here's the new generated HTML:
<form method="post">
<input type="text" name="foo" />
<button type="submit">Default</button>
<button type="submit" formaction="/?handler=Alternative">Alternative</button>
</form>
SECOND UPDATE
OK, so If I put asp-page-handler="" on the "default" button, then each button goes to the correct handler, which is fine.
The last question that remains, then, is: how can I make this work with the tag helper prefix?
[Answering my own question in case this helps others.]
It turns out that:
The tag-helper-prefix only applies to elements, not attributes, so it should be asp-page-handler="..." rather than x:asp-page-handler="..." even if the tag-helper-prefix is x:.
Those asp- attributes are only recognized within a tag that is tag-helper-enabled - which is all elements when no tag-helper-prefix is specified, or only elements with the tag-helper-prefix where one is specified. In my case, I had to change <button ...> to <x:button ...>.
If you specify asp-page-handler for one button, you need to specify it on all the buttons, even if you specify it as "" to get the default action.
Here are the codes:
<EditForm OnValidSubmit="#SubmitText" id="inputText">
<InputText #bind-Value="_InputMsgModel.Msg" />
</EditForm>
After the program ran, it turned out to be this:
<form id="inputText">
<input class="valid">
</form>
Now I wanna add an attribute type="text" to the input element, how can I achieve this?
I tried to modify the code like this:
<EditForm OnValidSubmit="#SubmitText" id="inputText">
<input type="text" #bind-Value="_InputMsgModel.Msg" />
</EditForm>
Meanwhile, now visual studio reports an error:
I can not bind the model anymore.
I need to set the type to text for needing to set the keyboard in mobile correctly.
How can I solve this? Thank you.
What is wrong with this code:
<EditForm Model="#_InputMsgModel" OnValidSubmit="#SubmitText" id="inputText" >
<InputText #bind-Value="#_InputMsgModel.Msg" />
</EditForm>
Run this code with the above:
#code {
InputMsgModel _InputMsgModel = new InputMsgModel();
private void SubmitText()
{
Console.WriteLine(_InputMsgModel.Msg);
}
public class InputMsgModel
{
public string Msg { get; set; } = "My new message";
}
}
Do you see the text "My new message" in the text box ? I believe you do... All is well, and the two-way binding mechanism works well. Go and see now the Html...it's still <input class="valid"> which does not reflect the real state of the text box. Think about it...
Update: Of course you can use the following:
<EditForm Model="#_InputMsgModel" OnValidSubmit="#SubmitText" id="inputText" >
<input type="text" #bind-value="#_InputMsgModel.Msg" />
</EditForm>
Important: The error "The attribute names could not..." is triggered because you use capital "V" in #bind-Value. You should use lower case: #bind-value. This is because your using input 'Html element' here, and it has a value attribute, not a Value attribute. But when you use the InputText Component, the capital Value in #bind-Value refers to a Value property defined in the component.
I have a simple select list in my Aurelia view which I'm trying to set a default value on of 'Select...'. I'm also using the aurelia-validation plugin to ensure that the value is changed before the form is submitted. The plugin works great for other field types in my project.
<div class="form-group">
<label for="agencies" class="control-label">Agency</label>
<select value.bind="agencyId" class="form-control">
<option value="">Select..</option>
<option repeat.for="agency of agencies" value.bind="agency.id">${agency.name}</option>
</select>
</div>
In the VM:
constructor(validation) {
this.agencies = null;
this.agencyId = 0;
this.validation = validation.on(this)
.ensure('agencyId')
.isNotEmpty();
}
activate() {
//call api and populate this.agencies
}
After the page initially loads I get my agencies in the list and my default value is correct, but it shows the validation error message:
Other form fields, like text boxes don't do this and show no error message until the user interacts with the form controls.
Is there something special I need to do for a select list to hide validation errors on the initial loading of the view? I suspect that binding the select list in the view is somehow triggering a change event.
Thanks to a kind Aurelia user on Gitter, the problem was solved by setting the initial value of this.agencyId to "". Originally I had the this.agencyId = null. That was my mistake. Because it was null and not "" (as was the default value in the select list) the values didn't match so the select list was invalid when the view loaded. At least, that's my understanding.
The lesson is, if you want to validate a select list, make sure you VM property is initialized to the same value as your select list's default value.
constructor() {
this.agencyId = ""; **//must match the bound property's initial value**
}
And in the view:
<div class="form-group">
<label for="agencies" class="control-label">Agency</label>
<select value.bind="agencyId" class="form-control">
<option value="" **<!-- this value must match the VM initial value -->** selected="true">Select...</option>
<option repeat.for="agency of agencies" value.bind="agency.id">${agency.name}</option>
</select>
</div>
I have 2 forms that I am testing using TestStack.Seleno. Both forms have a checkbox that is mandatory. The first form has (including the checkbox) 5 fields. I can use TestStack.Seleno to create a passing test with valid data. I set the checkbox like this:
Input.TickCheckbox(f=>f.Accept,form.Accept);
On my other form which has 10 or so fields, when I try to set the checkbox to be ticked (using the same code) nothing happens. However when I try
var acceptCheckBox = Find.Element(By.Name("Accept"),new TimeSpan(0,0,0,50));
if (form.Accept)
{
acceptCheckBox.Click();
}
I get error "Element is not currently visible and so may not be interacted with"
Element is clearly visible and is not injected in using javascript.
I am using latest version of TestStack.Seleno from github.
Any ideas?
So I have managed to figure out what the issue is and have a work around, however I cannot explain why it works on the other form. The mandatory Accept field has html generated by mvc that looks like
<div>
<input class="check-box" data-val="true" data-val-mustbetrue="The Accept our field is required" data-val-required="The Accept our field is required." id="Accept" name="Accept" type="checkbox" value="true"><input name="Accept" type="hidden" value="false">
<label for="Accept">
Accept our Please accept our Terms and Conditions
</label>
<span class="field-validation-valid" data-valmsg-for="Accept" data-valmsg-replace="true"></span>
</div>
So you have the checkbox and hidden field both with id Accept, I suspect in code seleno is picking up the hidden field and setting value, so I updated my code todo
var acceptCheckBox = Find.Element(By.CssSelector("#Accept.check-box"));
acceptCheckBox.Click();
Now everything works.
Ismail
Weird this one.
On my .NET MVC 4 project I've added a file on App_Code who contains this method:
#helper CheckBox(string name, bool isChecked = false, string className = "") {
<div class="checkboxHolder">
<input id="#name" name="#name" type="hidden" value="#isChecked") />
<i class="#className checkboxBts fa #((isChecked) ? "fa-check-square-o" : "fa-square-o")" data-checkbox-associated="#name"></i>
</div>
}
I'm using it to style checkboxes using font-awesome, so my app checkboxes are made of an input type hidden who stores a boolean value and an icon to give feedback to users.
Weird thing is, on executing when isChecked == false, the hidden returned by this method is like:
<input id="myCheckboxId" name="myCheckboxId" type="hidden" />
There is no value at all, when I try to save it to the model an exception is thrown saying that model cannot be saved.
I've fixed it changing the method to use:
<input id="#name" name="#name" type="hidden" #((isChecked) ? "value=true" : "value=false") />
Which is working fine. However, I wonder if anyone know what could be happening on the original output.
Thank you all.
It's not entirely a duplicate, but this is answered in Why is my hidden input writing: value=“value” instead of true/false?:
if you have:
<input name="somefield" type="hidden" someprop="#(SomeBooleanExpression)"/>
[and #SomeBooleanExpression] is false it is omitted completely:
<input name="somefield" type="hidden"/>
To get around this, consider .ToString()
So, use:
<input id="#name" name="#name" type="hidden" value="value="#(isChecked.ToString())" />