ASP.net Entity Framework Check if exists in database

Question

I have VS2015, entity framework 6. I have a database with one table (Logins)

FirstName, lastName, Birthdate, email, password

I also have a textbox(s), button

tbEmail tbpass and btnLogin

How do I check if the users email in the textbox matches one in the database?

So far I have:

 protected void btnLogin_Click(object sender, EventArgs e)
    {
            Logins Log = new Logins();

    using (LoginDataEntities lg = new LoginDataEntities())
    {
        string @email = tbUsernameL.Text;
        string @password = tbPassL.Text;

        var logged = from L in lg.Logins
                     where L.Username == @email
                     && L.Pass == @password
                     select L.Username;



        if (logged != null) 
        {
            lblSuccess.Visible = true;
        }
        else
        {
            lblFail.Visible = true;
        }


    }
}

However, its not working and always enables the success label. How do I fix this?

Carsten Cors · Accepted Answer · 2016-02-18 09:16:33Z

1

Try it once with the following snippet:

using (LoginDataEntities lg = new LoginDataEntities())
        {
            string @email = tbUsernameL.Text;
            string @password = tbPassL.Text;

            var logged = lg.Logins
.SingleOrDefault(l=> l.Username == @email && l.Pass == @password);

            if (logged != null) // update
            {
                lblSuccess.Visible = true;
            }
            else
            {
                lblFail.Visible = true;
            }
        }

Alternatively, can you also look at the following example again:

http://www.c-sharpcorner.com/uploadfile/b19d5a/custom-user-login-and-registration-page-in-Asp-Net-mvc3-with-razor-and-entity-framework/

Or you refactorisiers the VS template with Individual User Accounts

edited Feb 18, 2016 at 9:16

answered Feb 18, 2016 at 8:40

Carsten Cors

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2 Comments

wiredlime2015 Over a year ago

I am getting an error with SingleorDefault -- "Error CS1061 LoginDataEntities' does not contain a definition for 'SingleOrDefault' and no extension method 'SingleOrDefault' accepting a first argument of type 'LoginDataEntities' could be found"

Carsten Cors Over a year ago

Ops sry, lg.Logins.SingleOrDefault(l=> l.Username == @email && l.Pass == @password); i misst your entity, i will correct in my snippet..

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