“/”应用程序中的服务器错误。指定的转换无效

Question

我尝试运行此代码并弹出错误，具体转换无效。在添加任何 LINQ 之前做得很好。请帮忙谢谢。在添加任何 LINQ 之前仍然可以。但现在它无法加载用户数据库上下文。我不知道这是怎么发生的。请发送帮助谢谢。

ForumDBDataContext db = new ForumDBDataContext();
protected void Page_Load(object sender, EventArgs e)
{
    ValidationSettings.UnobtrusiveValidationMode = UnobtrusiveValidationMode.None;
}

protected void btnLogin_Click(object sender, EventArgs e)
{
    string emailAddress = txtEmail.Text;
    string password = txtpwd.Text;
    bool rememberMe = chkRememberMe.Checked;

    User u = db.Users.SingleOrDefault(
                x => x.EmailAddress == emailAddress &&
                x.Hash == Security.GetHash(password)
                );

    if (u != null)
    {
        DateTime currentDate = DateTime.Now;
        var query = from m in db.Members
                    where m.EmailAddress == emailAddress
                    select m.Last_Login_Date;

        Convert.ToDateTime(currentDate);
        DateTime lld = Convert.ToDateTime(query);
        int diffDays = DateTime.Compare(currentDate, lld);


        if (diffDays > 72)
        {
            Response.Redirect("ChangePwd.aspx");
        }
        else
        {
            Security.LoginUser(u.Name, u.Role, rememberMe);

        }
    }

Answer 1

您不能在 LINQ 中使用Security.GetHashmethod，因为此方法无法转换为 SQL。您需要在运行 LINQ 之前运行此方法并设置变量：

string emailAddress = txtEmail.Text;
string password = txtpwd.Text;
bool rememberMe = chkRememberMe.Checked;
var hashedPassword = Security.GetHash(password);

User u = db.Users.SingleOrDefault(
            x => x.EmailAddress == emailAddress &&
            x.Hash == hashedPassword 
            );