服务器端RequiredFieldValidators无法正常工作

Question

I have a form representing a survey that is dynamically generated based on some database configuration. I have a custom server control for rendering the survey ( SurveyRenderer ) which contains custom server controls for rendering questions ( QuestionRenderers ). I dynamically add RequiredFieldValidators for questions if they are flagged as being required. I add these validators to the SurveyRenderer 's control collection.

The gist of the code...

// In SurveyRenderer.CreateChildControls()...
foreach (QuestionRenderer questionRenderer in questionRenderers)
{
   if (questionRenderer.Question.IsRequired)
   {
       Controls.Add(CreateRequiredValidator(questionRenderer));
   }
}

The client-side validation works fine -- if someone has omitted a required question, the validators catch it and the form doesn't validate. However if I turn off JavaScript and submit an invalid form, the validators do not seem to work.

On the server-side I am calling Page.Validate() and checking Page.IsValid in the submit button click event handler. Despite submitting a form where required questions have been left blank - something that would be caught client-side - on the server-side Page.IsValid remains True .

// In SurveyPage.aspx...
public void btnSubmit_Click(object sender, EventArgs e)
{
   Page.Validate();
   if (Page.IsValid)
   {
       // Always get here, even though the form is not valid and would
       // have been caught client-side...
   }
}

Should I be adding the validators to the Page's Control collection, rather than the SurveyRenderer? How come it works on the client-side but not server-side?

UPDATE : My QuestionRenderer is annotated with:

[ValidationProperty("IsValid")]

And the IsValid get method is like so:

// QuestionRenderer.IsValid
public bool IsValid
{
    get
    {
        EnsureChildControls();
        if (Question.IsRequired && QuestionIsNotAnswered())
        {
            return false;
        }

        return true;
    }
}

If I set a breakpoint and step through, I can see that QuestionRenderer.IsValid is being fired OK. It is returning false when it should do. If I go fine-grained and call in btn_submitClick:

// In SurveyPage.aspx...
public void btnSubmit_Click(object sender, EventArgs e)
{
    foreach (IValidator validator in Page.Validators)
    {
        validator.Validate();  // this calls through to QuestionRenderer.IsValid, which returns false...
        bool valIsValid = validator.IsValid; // yet this is set to True
    }
}

So validator.IsValid is true, even though the call to QuestionRenderer.IsValid returns false. So maybe I haven't wired something up correctly? Is using [ValidationProperty("IsValid")] not enough?

Answer 1

actually, validation uses Page.Validators where all the validators are stored (the actual routine is quity tricky) - so it does not matter, where you add them.

source of BaseValidator

protected internal override void OnInit(EventArgs e)
{
    base.OnInit(e);
    this.Page.Validators.Add(this);
}

i would leave them in th view, as you could use object sender -parameter (which represents the validator) to get the associated control ...

i believe, your CreateChildControls - which does the attaching of the validators - is called to late, so it misses the validation phase ... could you maybe try to call EnsureChildControls in OnLoad -event, to see if it changes something? another chance might be, that your validators are not visible or disabled...

EDIT

according to your edits, i would encourage you to use a CustomValidator - a RequiredFieldValidator will return true on each case (property is true or false ), because it is not empty :)