If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. Hello
Im having problems in getting data from the related tables using selectedvalue in combobox. this is my code:

Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
      
  For Each c As Control In Me.Controls
            If TypeOf c Is GroupBox Then
                Me.Controls.Remove(c)
            End If
        Next
  
      Dim adptr As New MySqlCommand("SELECT * FROM positions WHERE election_id = ?election_id", conn)
        adptr.Parameters.Add("?election_id", MySqlDbType.Int32)
        adptr.Parameters("?election_id").Value = ComboBox1.SelectedValue
        Dim positions As New DataTable
        Dim positionAdapter As MySqlDataAdapter = New MySqlDataAdapter(adptr)
        positionAdapter.Fill(positions)

and error appeared to say:
Unable to cast object of type 'System.Data.DataRowView' to type 'System.IConvertible'.
Thanks in advance for anyone who could help me. You haven't set the ValueMember of your ComboBox. If you don't then the item itself is returned by SelectedValue. If you've bound a DataTable then each item is a DataRowView, not an individual field value. If you expect SelectedValue to return a value from a specific column of your table then you need to assign the name of that column to the ValueMember property of the ComboBox.

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Thanks can u pls give me an example how to set the valuemember for my combobox. im new into this type of application.
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