Content Item field validation best practice

[lbertonicsc]

Good morning,

I am currently validating the values of fields during the creation of a Content Item by using a Driver.
The example code is:

public class MyDriver : ContentDisplayDriver
{
    private readonly IStringLocalizer S;

    public MyDriver(IStringLocalizer<MyDriver> localizer)
    {
        S = localizer;
    }

    public override bool CanHandleModel(ContentItem model)
    {
        return (model.ContentType == "MyContentType")
    }

    public override async Task<IDisplayResult> UpdateAsync(ContentItem model, IUpdateModel updater)
    {
        await ValidateItemsAsync(model, updater);

        return await EditAsync(model, updater);
    }

    private async Task<bool> ValidateItemsAsync(ContentItem model, IUpdateModel updater)
    {
        // retrieve value of field
        TextField MyTextField = new TextField();
        await updater.TryUpdateModelAsync(
            MyTextField,
            string.Format("MyPart.MyTextField", _type),
            f => f.Text
        );

        bool IsValid = false;

        if ((MyTextField.Text is not null) && MyTextField.Text.Length > 160)
        {
            updater.ModelState.AddModelError(
                string.Format("MyPart.MyTextField.Text", _type),
                S["MyTextField allows a maximum of 160 characters. " +
                "You have inserted {0} characters.",
                MyTextField.Text.Length.ToString()]
            );
        }else{
            IsValid = true;
        }

        return IsValid;        
    }
}

Is this the proper way or is there a better way to do it?

Related discussion: #8963

[hishamco]

What you did is fine, but sometimes we do a validation on the UpdateAsync itself, have a look to some of our DisplayDrviers

[lbertonicsc]

Thank you, if you think appropriate leave the discussion open for further comments otherwise close it.

[ns8482e]

1cent - Use ViewModel instead of Part/Field - this way you can avoid untrusted updates (over posting) to ModelBinding