Question

I’m using AdventureWorks as a database to get familiar with linq and asp.net interface and was wondering if anyone could take a look at my code behind in C# and give me a optimized way to get the results populated when searched and then updated when submitted.

protected void btnSearch_Click(object sender, EventArgs e)
    {
        TestDataClassDataContext dc = new TestDataClassDataContext();
        Individual ind = new Individual();
        var q = from Individual in dc.Individuals
                where Individual.CustomerID == Convert.ToInt32(txtCustID.Text)
                select Individual;
        if (q.Count() > 0)
        {
            ind = q.First();
            Contact con = new Contact();
            var q2 = from Contact in dc.Contacts
                     where Contact.ContactID == ind.ContactID
                     select Contact;
            if (q2.Count() > 0)
            {
                con = q2.First();
                txtFname.Text = con.FirstName;
                txtLname.Text = con.LastName;
                txtMname.Text = con.MiddleName;
                txtPhone.Text = con.Phone;
                txtPword.Text = con.PasswordSalt;
                txtSuff.Text = con.Suffix;
                txtTitle.Text = con.Title;
                txtEmail.Text = con.EmailAddress;
                ddlEmailPromo.SelectedValue = con.EmailPromotion.ToString();

            }
        }
    }

    protected void btnSubmit_Click(object sender, EventArgs e)
    {
        TestDataClassDataContext dc = new TestDataClassDataContext();
        Individual ind = new Individual();
        var q = from Individual in dc.Individuals
                where Individual.CustomerID == Convert.ToInt32(txtCustID.Text)
                select Individual;
        if (q.Count() > 0)
        {
            ind = q.First();
            Contact con = new Contact();
            var q2 = from Contact in dc.Contacts
                     where Contact.ContactID == ind.ContactID
                     select Contact;
            if (q2.Count() > 0)
            {
                con = q2.First();
                con.FirstName = txtFname.Text;
                con.LastName = txtLname.Text;
                con.MiddleName = txtMname.Text;
                con.Phone = txtPhone.Text;
                con.PasswordSalt = txtPword.Text;
                con.Suffix = txtSuff.Text;
                con.Title = txtTitle.Text;
                con.EmailAddress = txtEmail.Text ;
                ddlEmailPromo.SelectedValue = con.EmailPromotion.ToString();

            }
        }

Answer 1

In one query:

TestDataClassDataContext dc = new TestDataClassDataContext();
var con = (from individual in dc.Individuals 
                 join contact in dc.Contacts on individual.ContactID equals contact .ContactID
                 where individual.CustomerID == Convert.ToInt32(txtCustID.Text)
                 select contact).FirstOrDefault();

if(con == null) return;

txtFname.Text = con.FirstName;
txtLname.Text = con.LastName;
txtMname.Text = con.MiddleName;
txtPhone.Text = con.Phone;
txtPword.Text = con.PasswordSalt;
txtSuff.Text = con.Suffix;
txtTitle.Text = con.Title;
txtEmail.Text = con.EmailAddress;
ddlEmailPromo.SelectedValue = con.EmailPromotion.ToString();

Use the same query into the submit changes function!