Thread: How to display data from database based on selected combobox value

Hello,

I'm having trouble in displaying the information based on the combobox selection. Here is my code so far

Private Sub cmbBoxIncidentDate_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmbBoxIncidentDate.SelectedIndexChanged
Dim dateValue As String
dateValue = cmbBoxIncidentDate.SelectedValue
Me.txtBoxIncidentType.Text = dateValue

'*------------------------------------------------------------------------------------------------------

Dim connString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Documents and Settings\Kasturi\My Documents\Visual Studio Projects\WindowsApplication1\db\test.mdb"
Dim Cmd As OleDbCommand
Dim Reader As OleDbDataReader
Dim SQL As String

Dim Con = New OleDbConnection(connString)

SQL = "SELECT * FROM [Incident] WHERE [Incident_Date] = " & dateValue & ""
Cmd = New OleDbCommand(SQL, Con)

Con.Open()


Con.Close()



End Sub

How do i reference the information needed to display in combo boxes? These are the fields in my database :- Incident_ID, Incident_Date, Incident_Name. Thanks in advance.

Note that if you want to specify a date literal in an SQL statement you should either enclose it in hash characters, e.g. #30/08/2005#, or use the DATEVALUE function (which may be Access-specific, although I'm not sure), e.g. DateValue('30/08/2005').

You can create a parameterised query and set the values of the parameters based on the selections from your ComboBoxes, e.g.

Code:

Dim selectCommand As New OleDbCommand("SELECT * FROM [Incident] WHERE [Incident_Date] = @Incident_Date", Con)

selectCommand.Parameters.Add("@Incident_Date", OleDbType.DBDate)

selectCommand.Parameters("@Incident_Date").Value = dateValue

Note that the command and parameter can be created at the class-level and thus reused. Then the only thing you need to do is set the parameter Value each time you want to perform a query.