Is my update query correct? sstudentid is the primary key of studentregister table? and can it be updated?

Private Sub editbtn_Click(sender As System.Object, e As System.EventArgs) Handles editbtn.Click
        If Not CheckEmptyTextbox(GroupBox1) Then
            Exit Sub
        End If

        If stucntcttxt.Text.Length <> 10 Then
            MsgBox("Contact Number Must Be 10 Characters Long", MsgBoxStyle.Information)
            Exit Sub
        End If

        Dim Valid As Boolean
        Try
            Valid = Regex.IsMatch(stuemailtxt.Text, "\A(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?)\Z", RegexOptions.IgnoreCase)
        Catch ex As Exception
        End Try
        If Not Valid Then
            MsgBox("Enter Valid Emailid", MsgBoxStyle.Information)
            Exit Sub
        End If

        'Dim con As New SqlConnection("Data Source=ASHUTOSH-PC\SQLEXPRESS;Initial Catalog=Art Station Management System;Integrated Security=True")
        Dim str As String
        Dim i = CInt(stuidcmb.Text)
        Dim a = CInt(stuagetxt.Text)
        Dim gender As String = String.Empty
        If stumalerd.Checked Then
            gender = "Male"
        ElseIf stufemalerd.Checked Then
            gender = "Female"
        End If

        con.Open()
        str = "Update StudentRegister set sname = @sname, smiddlename = @smiddlename, ssurname = @ssurname, sdob = @sdob, ccoursename = @ccoursename, btbatchid = @btbatchid, sage = @sage, sgender = @sgender,scontact = @scontact,saddress = @saddress,semailid = @semailid, sdatereg=@sdatereg where sstudentid = @sstudentid"
        com = New SqlCommand(str, con)
        com.Parameters.AddWithValue("@sstudentid", stuidcmb.Text)
        com.Parameters.AddWithValue("@sname", stufnametxt.Text)
        com.Parameters.AddWithValue("@smiddlename", stumnametxt.Text)
        com.Parameters.AddWithValue("@ssurname", stulnametxt.Text)
        com.Parameters.AddWithValue("@sdob", birthdate.Value.Date)
        com.Parameters.AddWithValue("@ccoursename", coursenamecmb.Text)
        com.Parameters.AddWithValue("@btbatchid", batchidcmb.Text)
        com.Parameters.AddWithValue("@sage", a)
        com.Parameters.AddWithValue("@sgender", gender)
        com.Parameters.AddWithValue("@scontact", stucntcttxt.Text)
        com.Parameters.AddWithValue("@saddress", stuaddtxt.Text)
        com.Parameters.AddWithValue("@semailid", stuemailtxt.Text)
        com.Parameters.AddWithValue("@sdatereg", regdate.Value.Date)
        com.CommandText = str
        com.ExecuteNonQuery()
        con.Close()
        MsgBox("Record Edited Successfully", MsgBoxStyle.Information)
        Display()
        clear()

    End Sub