How to validate against Multiple validation groups?

Question

I have two validation groups: parent and child

I have an add button that needs to only validate the child validation group which is easily done. The save button ne

Answer 1

Whatever way you do it requires some hacking to get round ASP.Net's assumption that you wouldn't try to do this. I favour a reusable approach which is explicit about the hackery involved.

using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace WebSandbox.Validators
{
    /// 

    ///   
    ///     Validates a different validation group. Among the use cases envisioned are
    ///     
    ///       
    ///         Validating one set of rules when the user clicks "Save draft" and validating those rules plus some
    ///         extra consistency checks when they click "Send".
    ///       
    ///       
    ///         Grouping controls in a fieldset into a validation group with a
    ///         ValidationSummary and then having a final ValidationSummary which tells the
    ///         user which groups still have errors.
    ///       
    ///     
    ///   
    ///   
    ///     We include checks against setting GroupToValidate to the same value as
    ///     ValidationGroup, but we don't yet include checks for infinite recursion with one validator
    ///     in group A which validates group B and another in group B which validates group A. Caveat utilitor.
    ///   
    /// 
    public class ValidationGroupValidator : BaseValidator
    {
        public string GroupToValidate
        {
            get { return ViewState["G2V"] as string; }
            set { ViewState["G2V"] = value; }
        }

        protected override bool ControlPropertiesValid()
        {
            if (string.IsNullOrEmpty(GroupToValidate)) throw new HttpException("GroupToValidate not specified");
            if (GroupToValidate == ValidationGroup) throw new HttpException("Circular dependency");
            // Don't call the base, because we don't want a "control to validate"
            return true;
        }

        protected override void AddAttributesToRender(HtmlTextWriter writer)
        {
            base.AddAttributesToRender(writer);

            writer.AddAttribute("evaluationfunction", "ValidateValidationGroup");
            writer.AddAttribute("GroupToValidate", GroupToValidate);
        }

        protected override void OnPreRender(EventArgs e)
        {
            // The standard validation JavaScript is too restrictive for this validator to work, so we have to replace a key function.
            // Fortunately this runs later than the standard JS, so we can simply overwrite the existing value of Page_ClientValidate.
            Page.ClientScript.RegisterStartupScript(typeof(ValidationGroupValidator), "validationJS", _ValidationJS);

            base.OnPreRender(e);
        }

        protected override bool EvaluateIsValid()
        {
            if (string.IsNullOrEmpty(GroupToValidate)) return false;

            bool groupValid = true;
            foreach (IValidator validator in Page.GetValidators(GroupToValidate))
            {
                validator.Validate();
                groupValid &= validator.IsValid;
            }

            return groupValid;
        }

        private const string _ValidationJS = @"";
    }
}