How to connect to db sql using c# for login

[Vapatamge]

This is my cod e for login:\[code\] protected void Button2_Click(object sender, EventArgs e) { /*try {*/ string s3 = "select Password from Login where LName='" + TextBox1.Text + "'"; SqlCommand cmd1 = new SqlCommand(s3); SqlDataReader psd; psd = cmd1.ExecuteReader(); string s2 = "select LName from Login where LName='" + TextBox1.Text + "'"; SqlCommand cmd = new SqlCommand(s2); SqlDataReader Ln; Ln = cmd.ExecuteReader(0); string s1 = "select LoginType from Login where LName='" + TextBox1.Text + "'"; SqlCommand cmd2 = new SqlCommand(s1); SqlDataReader da; da = cmd2.ExecuteReader(); if (Ln.Read() && psd.Read()) { if (da.ToString() == "Candidate") { Response.Redirect("CandidateDetails.aspx"); } else if (da.ToString() == "Administartor") { Response.Redirect("WebForm1.aspx"); } } else { Response.Write("Not Authonticated"); } /*} catch (InvalidOperationException) { }*/ }\[/code\]I am getting error while running:ExecuteReader: Connection property has not been initialized.in " psd = cmd1.ExecuteReader();"