how to create unique identity based on comboboxes text selection in visual basic 2010 form

Question

hello world,

i have a form which is having combo boxes which is connected with ms access database.

i am using following code to fill combo boxes:

Private Sub loadcourse()
        Dim OleDBC As New OleDbCommand
        Dim OleDBDR As OleDbDataReader
        With OleDBC
            .Connection = conn
            .CommandText = "SELECT coursename FROM tblcourse"
        End With
        OleDBDR = OleDBC.ExecuteReader
        cmbcourse.Items.Clear()

        If OleDBDR.HasRows Then
            While OleDBDR.Read
                cmbcourse.Items.Add(OleDBDR.Item(0))

            End While
        End If
    End Sub

    Private Sub loadcourseyear()
        Dim OleDBC As New OleDbCommand
        Dim OleDBDR As OleDbDataReader
        With OleDBC
            .Connection = conn
            .CommandText = "SELECT courseyear FROM tblcourseyear"
        End With
        OleDBDR = OleDBC.ExecuteReader
        cmbcourseyear.Items.Clear()

        If OleDBDR.HasRows Then
            While OleDBDR.Read
                cmbcourseyear.Items.Add(OleDBDR.Item(0))
                
            End While
        End If
    End Sub

now i am filling my textbox1 with these code:

Private Sub cmbcourse_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmbcourse.SelectedIndexChanged

        If cmbcourse.Text = "B.A." Then
           txtrollnumber.Text = "201301"

        End If
        If cmbcourse.Text = "M.A." Then
            txtrollnumber.Text = "201302"
        End If
        If cmbcourse.Text = "B.Sc." Then
            txtrollnumber.Text = "201303"
        End If



    End Sub

    Private Sub cmbcourseyear_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmbcourseyear.SelectedIndexChanged
        If cmbcourseyear.Text = "I" Then
            txtrollnumber.Text = txtrollnumber.Text + "01"
        End If
        If cmbcourseyear.Text = "II" Then
            txtrollnumber.Text = txtrollnumber.Text + "02"
        End If
        If cmbcourseyear.Text = "III" Then
            txtrollnumber.Text = txtrollnumber.Text + "03"
        End If
    End Sub

as you can see i just want to create a unique ID with course selection and courseyear selection i.e.

if i select "B.A." from cmbcourse and "II" form cmbcourseyear the textbox fills with number - 20130102 this is because i want to save data year wise.

now i want to add 0001,0002,0003 and so.no........ in front of the number in the textbox in increment order. so that whenever the comboboxes selected the next number must find from the database and in front of textbox number.

the form have two buttons

1.SAVE

2.ADD

when SAVE click the data from form must save in database table.

is it possible when i click ADD button the textbox should clear and fill with selection of cmbcourse and after that selection of cmbcourseyear and then find the max number from the access database table and fill the total rollnumber.

sorry for my pure explanation because i am new in vb.net and trying to do some thing for our institution.

i am using this process because i want to save record in YEAR-WISE.

is it any way to make program more useful

please solve my problem with code help.

thanks in advanced.

Answer 1

Hi,

you need to learn more about database and SQL query.

Instead of asking code, please google OR learn more about basic knowledge. If the following code is WRITTEN by you, I'm sure there will be no issue about your question. 

Writing SQL Queries: Let's Start with the Basics:http://msdn.microsoft.com/en-us/library/bb264565(v=sql.90).aspx

ADO.NET Overview:http://msdn.microsoft.com/en-us/library/h43ks021(v=VS.100).aspx

---

No code, No fact.

Answer 2

hi,

thanks for reply

as u can see the second part of code is written by me.

but i don't know how to proceed further.

please help me. 

Answer 3

hi,

for adding the Text to the TextBox you can use Append method of TextBox as....

TextBox.Append()

For Unique Id you can check database to give the next unique id to that row...and increment it by 1 for next id...