how to check if an email address already exists in the database in asp.net

In this article we can see how to find exiting email id from data base and it will display error message if it already exits
We created a method with name uniqueEmail.
Established a connection to the database.
Getting the data from the table  aspnet_Membership.
Using the ExecuteReader to read the values and checking the condition weather email id is already exists or not.

   public bool uniqueEmail()
        {
            
                string iemail;
                string constr = ABCDataAccessLayer.ABCConnctionString; // connection string
                SqlConnection con = new SqlConnection(constr);
                con.Open();
                string query = "select count(Email) as Email  from aspnet_Membership where Email= '" + txtEmailID.Text + "'";
                SqlCommand cmd = new SqlCommand(query, con);
                SqlDataReader dr;
                dr = cmd.ExecuteReader();
                while (dr.Read())
                {
                    iemail = dr["Email"].ToString();
                    if (iemail != "0")
                    {
                        mailerror.Text = "Enter different email id";
                        return false;
                    }
                   
                }

                return true;
            
        }

Keep if condition,if you want to check email in insert mode or update mode
if (uniqueEmail())
{
Insert Code logic //
or
Update Code Logic
}

Output:

Read More»