I'm trying Microsoft Blazor and when working with forms and validation I stopped on how can I change the default CSS class that will be added by default on InputText
Validation State.
For Explanation when InputText
has an error by default take class " invalid
" I want to change this class to " is-invalid
"
I need best practices.
Thanks, StackOverflow community
Any HTML element (or InputText) attribute including the class, can be 'one-way' bound to a variable or expression. So in your case, you could do:
<input type="text" class="@((any_validation_condition)? "error_css_class" : "")" />
or just bind to a variable and set that variable at run-time to reflect the suitable display class of the element.
Thanks
Blazor has arbitrarily picked invalid
as the css class for InputBase<T>
based items' validation, like InputText
. You can however create a new control like MyInputText.razor
inherit from these and make your own control and put intermediary code in place.
In this case you can string replace (but prepend with space character!) the CssClass
property replacing invalid
for is-invalid
, and/or valid
for is-valid
. You could make a helper method or simply do it inline:
@inherits Microsoft.AspNetCore.Components.Forms.InputText
<input @attributes="@AdditionalAttributes" class="@CssClass.Replace(" valid", " is-valid").Replace(" invalid", " is-invalid")" @bind="@CurrentValueAsString" />
and use it as you would a normal InputText
:
<MyInputText @bind-Value="yourModel.Foo" class="form-control" />
Yes true it's customizable in Core 5.0, but the examples given is not working as is. The method HandleSubmit
must take EditContext
as argument, and the custom FieldCssClassProvider
be set there, not in OnInitialized()
as in the examples.
private async Task HandleSubmit(EditContext context)
{
context.SetFieldCssClassProvider(new MyFieldClassProvider());
var isValid = context.Validate();
if (isValid)
{
//...
}
else
{
//...
}
My MyFieldClassProvider()
returns " is-valid
" and " is-invalid
" and this works with Bootstrap.
This is now customizable, see here: https://docs.microsoft.com/en-us/aspnet/core/blazor/forms-validation?view=aspnetcore-5.0#custom-validation-class-attributes
var editContext = new EditContext(model);
editContext.SetFieldCssClassProvider(new MyFieldClassProvider());
...
private class MyFieldClassProvider : FieldCssClassProvider
{
public override string GetFieldCssClass(EditContext editContext,
in FieldIdentifier fieldIdentifier)
{
var isValid = !editContext.GetValidationMessages(fieldIdentifier).Any();
return isValid ? "good field" : "bad field";
}
}
As an addition to @user774031 answer: Blazor Framework Adds an Id to Isolated css class to make them scoped to Razor component but since this Id attribute added on Runtime, they do not add to child InputComponent and so the css class defined using css isolation do not apply and we should define them globally. To make them work as isolated css class define them as below for example: 1- Define a.Net class which inherit from FieldCssClassProvider
and override its GetFieldCssClass
method. This method should return some string
as classname from editcontext
and fieldIdentifier
object.
public class MyCustomeCSSProvider : FieldCssClassProvider
{
public override string GetFieldCssClass(EditContext editContext, in FieldIdentifier fieldIdentifier)
{
string className = string.Empty;
if (editContext.IsModified(fieldIdentifier))
{
className += " modifiedField";
}
if (editContext.GetValidationMessages(fieldIdentifier).Any())
{
className += " invalidField";
}
else
{
className += " validField";
}
return className;
}
}
2- in OnInitialized
life cycle Set CssClassProvider for edit context using extension method:
_context = new EditContext(student);
_context.SetFieldCssClassProvider(new MyCustomeCSSProvider());
3- Define your class in isolated css files as below using ::deep
:
::deep .validField {
border-color: lawngreen;
}
::deep .invalidField {
background-color: tomato;
}
::deep .modifiedField {
border: yellow dashed 2px;
}
Bit late the party on this one but to style the validation messages themselves I did this:
<div class="text-danger mt-2">
<ValidationMessage For="()=>_model.Field" ></ValidationMessage>
</div>
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