Core algorithms deployed

http://cstheory.stackexchange.com/questions/19759/core-algorithms-deployed/19773#19773

How to implement minimum string length validation by Data annotation in ASP.NET MVC?

Two ways:

Fisrt:

        [StringLength(50, ErrorMessage = "The {0} must be at least {2} characters long.", MinimumLength = 10)]

 

Second:

Regular expression

[RegularExpression(@"^.{10,}$", ErrorMessage = "Minimum 10 characters required")]

How to set base URL in ASP.NET MVC for JavaScript?

In _Layout.cshtml, Add base tag in head, and pass base URL.

<head>
    <base href='@string.Format("{0}://{1}{2}", Request.Url.Scheme, Request.Url.Authority, Url.Content("~"))'/>
</head>

How to fix problem: To call this method, the "Membership.Provider" property must be an instance of "ExtendedMembershipProvider"?

Because you are using SimpleMembership provider.
Either remove any other membership provider setting in web.config
Or
you add following setting in web.config file

Reference:
http://weblogs.asp.net/jgalloway/archive/2012/08/29/simplemembership-membership-providers-universal-providers-and-the-new-asp-net-4-5-web-forms-and-asp-net-mvc-4-templates.aspx

How to change password format in SimpleMembership?

No. Can't change password format like: SqlMembershipProvider.PasswordFormat