Microsoft KB Archive/135546

= How to Use a Multi-Select List Box to Filter a Form =

Article ID: 135546

Article Last Modified on 1/19/2007

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APPLIES TO


 * Microsoft Access 95 Standard Edition
 * Microsoft Access 97 Standard Edition

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This article was previously published under Q135546



Moderate: Requires basic macro, coding, and interoperability skills.



SUMMARY
This article shows you how to use a multiple-selection list box to restrict records in a recordset. The two methods described in this article are more flexible than other techniques, such as applying a query or an SQL WHERE clause because they enable you to choose at random which records are displayed.

This article assumes that you are familiar with Visual Basic for Applications and with creating Microsoft Access applications using the programming tools provided with Microsoft Access. For more information about Visual Basic for Applications, please refer to your version of the "Building Applications with Microsoft Access" manual.



MORE INFORMATION
Both of the following methods work by restricting the records in a recordset based on the items that you select in a multiple-selection list box.

Method 1
This method uses the Filter property of a form. To create this method, follow these steps:

 Open the sample database Northwind.mdb. Create a new, blank form based on the Customers table and open it in Design view. If the field list is not displayed, on the View menu, click Field List and drag the CustomerID and CompanyName fields from the field list to the detail section of the form.  Add an unbound list box to the form's detail section and set its properties as follows:   Name: List0 Row Source: Customers Column Count: 2 Column Widths: .5";2" Multi Select: Extended Width: 2.5"                    Add a command button to the form. Set the Name property to Command2, and set the OnClick property to [Event Procedure].  On the View menu, click Code, and type the following text in the Form module:  Option Compare Database Option Explicit

Private Sub Command2_Click

Dim Criteria As String Dim i As Variant

' Build criteria string from selected items in list box. Criteria = "" For Each i In Me![List0].ItemsSelected If Criteria <> "" Then Criteria = Criteria & " OR " End If     Criteria = Criteria & "[CustomerId]='" _ & Me![List0].ItemData(i) & "'" Next i

' Filter the form using selected items in the list box. Me.Filter = Criteria Me.FilterOn = True

End Sub </li> Open the form in Form view.</li> Select multiple items in the list box: click the first item, then hold down the CTRL key, and click subsequent items.</li> Click the command button. Note that the form's recordset is restricted to the records that you selected in the list box. If you clear the items and click the button again, you remove the filter and restore all the records.</li></ol>

Method 2
This method modifies the QueryDef object of a query. To create this method, follow these steps:

<ol> Open the sample database Northwind.mdb.</li> Create a new query based on the Orders table and include all the fields. Save the query as MultiSelect Criteria Example.</li> Create a new, blank form based on the Customers table and open it in Design view.</li>  Add an unbound list box to the form's detail section and set its properties as follows: <pre class="fixed_text">  Name: List0 RowSource: Customers ColumnCount: 2 ColumnWidths: .5";2" Multiselect: Extended Width: 2.5"                   </li>  Add a command button to the form. Set the Name property to Command4 and set the OnClick property to the following event procedure:

NOTE: This example uses the ItemData property to return values from the Bound Column of the list box. To return a value from a column other than the Bound Column use the Column property instead of the ItemData property. Private Sub Command4_Click

Dim Q As QueryDef, DB As Database Dim Criteria As String Dim ctl As Control Dim Itm As Variant

' Build a list of the selections. Set ctl = Me![List0]

For Each Itm In ctl.ItemsSelected If Len(Criteria) = 0 Then Criteria = Chr(34) & ctl.ItemData(Itm) & Chr(34) Else Criteria = Criteria & "," & Chr(34) & ctl.ItemData(Itm) _ & Chr(34) End If  Next Itm

If Len(Criteria) = 0 Then Itm = MsgBox("You must select one or more items in the" & _       " list box!", 0, "No Selection Made") Exit Sub End If

' Modify the Query. Set DB = CurrentDb Set Q = DB.QueryDefs("MultiSelect Criteria Example") Q.SQL = "Select * From Orders Where [CustomerID] In(" & Criteria & _    ");" Q.Close

' Run the query. DoCmd.OpenQuery "MultiSelect Criteria Example"

End Sub </li> Open the form in Form view.</li> Select multiple items in the list box by holding down the CTRL key and clicking the different items.</li> Click the command button. Note that the query is restricted to the records that you selected in the list box.</li></ol>

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