您可以在Startup.cs中配置该值

.AddSaml2("IDP", "IDP", opt =>
{
    opt.SPOptions = new Sustainsys.Saml2.Configuration.SPOptions
    {
        EntityId = new EntityId(ipdUrl),
        ReturnUrl = new Uri(webSiteUrl),
        ModulePath = string.Format("/saml2/{0}", "idp"), 
        AuthenticateRequestSigningBehavior = SigningBehavior.Always,
        MinIncomingSigningAlgorithm = "http://www.w3.org/2000/09/xmldsig#rsa-sha1"
    };

    RequestedAttribute requestedAttributeEmail = new RequestedAttribute("email");
    requestedAttributeEmail.FriendlyName = "Email";
    requestedAttributeEmail.NameFormat = RequestedAttribute.AttributeNameFormatBasic;
    requestedAttributeEmail.IsRequired = false;

    AttributeConsumingService attributeConsumingService = new AttributeConsumingService();

    attributeConsumingService.RequestedAttributes.Add(requestedAttributeEmail);

    attributeConsumingService.ServiceNames.Add(new LocalizedName("Required attributes", "en"));
    attributeConsumingService.IsRequired = true;
    attributeConsumingService.Index = 1;
    attributeConsumingService.IsDefault = true;

    opt.SPOptions.AttributeConsumingServices.Add(attributeConsumingService);    
});