populating the combobox based on the selected item in the first combobox

[sheela gupta]

I want to populate the combobox based on the selected item in the first combobox

The following code is written in vb.net 2008

Public Class Form1
    Sub fillcombo()
        strsql = "select * from device"
        Dim cmd As New OleDb.OleDbCommand
        cmd.CommandText = strsql
        cmd.Connection = con
        dr = cmd.ExecuteReader
        While (dr.Read())
            ComboBox1.Items.Add(dr("device"))
        End While
        cmd.Dispose()
        dr.Close()
 
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Module1.connect()
        Me.fillcombo()
    End Sub
 
    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        strsql = "select part from part where device='" & ComboBox1.Text & "'"
        Dim cmd As New OleDb.OleDbCommand
        cmd.CommandText = strsql
        cmd.Connection = con
        dr = cmd.ExecuteReader
        If (dr.Read() = True) Then
            ComboBox2.Text = (dr("part"))
        End If
        cmd.Dispose()
        dr.Close()
    End Sub
End Class

for this code I am able to populate the first combobox and when i select the specific item in combobox then the second combobox shows oly the first element of that item

In MS access 2007 i hav created 2 tables:
1)contains the device ex:computer
2)contains the device and its parts ex:cpu,monitor so here the device has duplicate values

table names are device and parts
guys help!!!!!

[Seth Schrock]

Check out this discussion: Cascaded Form Filtering

[sheela gupta]

I am doing a project which has front end of vb.net and back end of ms access.The main focus is on vb.net just for the database purpose i am using access.

I want to link the database to the vb.net program just for accessing the data from the database.

[Frinavale]

In your ComboBox1_SelectedIndexChanged method...
You are setting the ComboBox2's Text property over and over again in your loop instead of populating the ComboBox2 with items.

-Frinny

[sheela gupta]

so what should i change in that to populate

[Frinavale]

Do the same thing you are doing in the fillcombo to fill the first combo box ;)

-Frinny

[Monty sing]

Private Sub ComboBox_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox.SelectedIndexChanged
 
ComboSecond.items.add(ComboFirst.Items.Item(Me.ComboFirst.SelectedIndex)
 
End sub

Use above code on SelectedIndexChanged Event

[Frinavale]

Monty,

Sheela doesn't want to populate the second ComboBox with the same item as the firstComboBox...she wants to populate the second ComboBox based on what was selected in the first ComboBox.

The only problem in her posted code is that she's setting the Text property of the second ComboBox instead of adding items to the combo box.

To fix the problem she just has to change one line of code:

 Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        strsql = "select part from part where device='" & ComboBox1.Text & "'"
        Dim cmd As New OleDb.OleDbCommand
        cmd.CommandText = strsql
        cmd.Connection = con
        dr = cmd.ExecuteReader
        If (dr.Read() = True) Then
        'The following line needs to be changed 
        '    ComboBox2.Text = (dr("part"))
        'To this:
             ComboBox2.Items.Add(dr("part"))
        End If
        cmd.Dispose()
        dr.Close()
    End Sub