How to create EmailAdressAttribute only for G-mail

[meriah]

To validate the entry control email Use EmailAdressAttribute♪ One way to point out that the allowable house is gmail.com?

[emran]

We can look at implementation. EmailAddressAttribute ♪ http://referencesource.microsoft.com/#System.ComponentModel.DataAnnotations/DataAnnotations/EmailAddressAttribute.cs and set up its aribut for validation, slightly relaying the regular expression:

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter, AllowMultiple = false)]
public sealed class GmailAddressAttribute : DataTypeAttribute
{
    private static Regex _regex = new Regex(@"^((([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+(\.([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+)*)|((\x22)((((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(([\x01-\x08\x0b\x0c\x0e-\x1f\x7f]|\x21|[\x23-\x5b]|[\x5d-\x7e]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(\\([\x01-\x09\x0b\x0c\x0d-\x7f]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))))*(((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(\x22)))@gmail\.com$", RegexOptions.Compiled | RegexOptions.IgnoreCase | RegexOptions.ExplicitCapture);
public GmailAddressAttribute()
    : base(DataType.EmailAddress)
{
    ErrorMessage = "The {0} field is not a valid e-mail address.";
}

public override bool IsValid(object value)
{
    if (value == null) {
        return true;
    }

    string valueAsString = value as string;
    return valueAsString != null && _regex.Match(valueAsString).Length > 0;
}

}