Add class_name option for Models used in ModelForm

[ibe-314]

Currently when using ModelForm every form field is put into a new row. Here is an example:

The form above is generated using FastUIs ModelForm with the following pydantic Model:

class ExampleModel(BaseModel):
    first_name: Optional[str] = Field(
        None, title='First Name'
    )
    family_name: Optional[str] = Field(
        None, title='Family Name'
    )
    birth_date: Optional[date] = Field(None, title='Birth Date')
    remark: Optional[str] = Field(None, title='Remark')
    info: Annotated[Optional[str], Textarea(rows=5)] = Field(None, description='Optional free text information about you.')
    repo: str = Field(json_schema_extra={'placeholder': '{org}/{repo}'}, title='GitHub repository')

I would like to allign mutliple fields in one row using Bootstraps row and column functionality. I was not able to do this using ModelForm, however I found a solution using the Form class from fastui.components.forms:

manuel_model = c.Form(
        form_fields=[
            FormFieldInput(
                name="first_name",
                title="First Name",
                class_name="+ col-sm-4",
            ),
            FormFieldInput(
                name="family_name",
                title="Family Name",
                class_name="+ col-sm-4",
            ),
            FormFieldInput(
                name="birth_date",
                title="Birth Date",
                html_type="date",
                class_name="+ col-sm-4",
            ),
            FormFieldInput(
                name="remark",
                title="Remark",
                class_name="+ col-sm-6",
            ),
            FormFieldTextarea(
                name="info",
                title="Info",
                class_name="+ col-sm-6",
            ),
            FormFieldInput(
                name="repo",
                title="GitHub repository",
                class_name="+ col-sm-12",
            )
        ],
        submit_url="/api/login",
        class_name="+ row",
    )

which results in

I looked into the code of ModelForm, where the model_json_schema_to_fields function renders the Pydantic Model. Is there currently some possiility to add class_name attributes to the ModelForm fields? Or some other possibility to get the second layout using the ModelForm class?

[samuelcolvin]

ye we could allow a class name per field wrapper.

For my part, on the vast majority of fields where FastUI might realistically be used, I'm pretty happy with a single column of fields.