ACC2: Moving List Box Items from One List Box to Another

ID: Q132137

The information in this article applies to:

Microsoft Access 2.0

SUMMARY

This article describes how you can create a form that has two list boxes that imitate the multiple-selection capability reflected in Microsoft Access Wizards.

This method uses a Yes/No field in the table to indicate which records are selected. One list box displays the Yes records and the other displays the No records. To move items from one list box to the other, the Yes/No field of the selected record is set to the appropriate state and the list boxes are then requeried to update their respective lists.

Note that the method provided is suitable for single-user environments only. If this method is used in a multiuser environment, what one user does may interfere with the actions of another. See the "References" section later in this article for more information on a multiuser technique.

MORE INFORMATION

In addition to the two list boxes, the form also contains three command buttons. By using the command buttons, you can add items to, or delete items from the list box. You can also double-click an item in a list box to move it to the other list box. To create the form, follow these steps:

Open the sample database NWIND.MDB and create the following new table:


      Table: Table1
      ---------------------------------------------------
      Field Name: List
         Data Type: Text
         Field Size: 15
         Caption: Items that will be provided in list
      Field Name: Selected
         Data Type: Text
         Field Size: 5
         Caption: Indicates if the item has been selected

      Table Properties: Table1
      ------------------------
      PrimaryKey: List

View the Table1 table in Datasheet view. Add five records to the table. For each record, type any text in the List field (for example, a list of colors or cities), and then type YES in the Selected field.

Create the following new query based on the Table1 table and save it as Select Yes:


      Query: Select Yes
      -------------------------------
      Field: List
         Show: Yes
         Criteria: [selected] = "YES"

Create another new query based on the Table1 table as follows and save it as Select No:


      Query: Select No
      ------------------------------
       Field: List
         Show: Yes
         Criteria: [selected] = "NO"

Create a new blank form and save it as SelectList.

With the SelectList form open in Design view, click Code on the View menu, and then type the following line in the form module's Declarations section:
```
       Option Explicit 
```

Type the following three functions in the form module:


       '=======================================================
       ' The following function opens the table and changes the
       ' selected value from YES to NO, and then runs the
       ' query for the two list boxes so that they will display
       ' the updated values.
       '=======================================================


       Function Add ()
          Dim MyDB As Database
          Dim MyTable As Recordset
          Dim y As Control

          Set y = Me![Field0]

          If IsNull(y) Then
             MsgBox "Please select something in the list."
          Else
             Set MyDB = DBEngine.Workspaces(0).Databases(0)
             Set MyTable = MyDB.OpenRecordset("Table1")

             MyTable.Index = "PrimaryKey"
             MyTable.Seek "=", y

             MyTable.Edit
             MyTable.[Selected] = "no"
             MyTable.Update

             MyTable.Close
             Me![Field0].Requery
             Me![Field2].Requery
          End If
       End Function

       '=======================================================
       ' The following function opens the table and changes the
       ' selected value from NO to YES, and then runs the
       ' query for the two list boxes so that they will display
       ' the updated values.
       '=======================================================

       Function Del ()
          Dim MyDB As Database
          Dim MyTable As Recordset
          Dim y As Control

          Set y = Me![Field2]

          If IsNull(y) Then
             MsgBox "Please select something in the list."
          Else
             Set MyDB = DBEngine.Workspaces(0).Databases(0)
             Set MyTable = MyDB.OpenRecordset("Table1")

             MyTable.Index = "PrimaryKey"
             MyTable.Seek "=", y

             MyTable.Edit
             MyTable.[Selected] = "yes"
             MyTable.Update

             MyTable.Close
             Me![Field0].Requery
             Me![Field2].Requery
          End If
       End Function

       '=======================================================
       ' The following function sets all values in the Selected
       ' field to YES, and then runs the query for the two list
       ' boxes so that they will display the updated values.
       '=======================================================
       Function Clear ()
          Dim MyDB As Database
          Dim MyTable As Recordset

          Set MyDB = DBEngine.Workspaces(0).Databases(0)
          Set MyTable = MyDB.OpenRecordset("Table1")

          On Error GoTo erhandle

          MyTable.MoveFirst
          Do Until MyTable.EOF
            MyTable.Edit
            MyTable.[Selected] = "yes"
             MyTable.Update
              MyTable.MoveNext
          Loop

          MyTable.Close
          Me![Field0].Requery
          Me![Field2].Requery

          erhandle:
             Resume Next

       End Function

Save and close the form module. Then, add the following list box and command button controls to the SelectList form:


      List Box:
      -----------------------------
      Name: Field0
         RowSourceType: Table/Query
         RowSource: Select Yes
         OnDblClick: =Add()

      List Box:
      -----------------------------
      Name: Field2
         RowSourceType: Table/Query
         RowSource: Select No
         OnDblClick: =Del()

      Command Button:
      --------------------
      Name: Button One
         Caption: Clear
         OnClick: =Clear()

      Command Button:
      --------------------
      Name: Button Two
         Caption: Add Item
         OnClick: =Add()

      Command Button:
      -----------------------
      Name: Button Three
         Caption: Delete Item
         OnClick: =Del()

View the SelectList form in Form view. Note that the first list box, Field0, displays all the items in Table1 you can select. You can use the Clear, Add Item, or Delete Item buttons to add or remove items from the second list box, Field2. You can also double-click an item in a list box to move it to the other list box.

REFERENCES

For more information about how to select more than one item from the same list box (using an array), see the following article in the Microsoft Knowledge Base:

Q121356 ACC2: How to Create a Multiple-Selection list box

Additional query words: combo fill


Keywords          : kbusage FmsCmbo 
Version           : 2.0
Platform          : WINDOWS 
Issue type        : kbhowto

Last Reviewed: April 29, 1999