Microsoft KB Archive/231164

= OL98: How to Populate a List Box or Combo Box =

Article ID: 231164

Article Last Modified on 11/23/2006

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APPLIES TO


 * Microsoft Outlook 98 Standard Edition

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This article was previously published under Q231164





SUMMARY
This article describes how to populate a list box or combo box control on an Outlook custom form.

NOTE: This article does not directly apply to using a Visual Basic for Applications UserForm, although some of the approaches in this article may be applied to UserForms.



MORE INFORMATION
There are a variety of ways to populate a list box or combo box on an Outlook form. The controls can be populated either at design-time or at run-time.

Populating List Boxes and Combo Boxes at Design-Time
If you have a predetermined and unchanging set of possible values, you can populate list boxes and combo boxes when designing the form. The following steps illustrate how to set up a simple list box control on an Outlook form.


 * 1) On the Tools menu, point to Forms, and then click Design a Form.
 * 2) In the Standard Forms Library, click Message, and then click Open.
 * 3) Click the (P.2) tab.
 * 4) On the Form menu, click Control Toolbox. On the Control Toolbox, drag a ListBox onto the form.
 * 5) Right-click the list box and then click Properties. On the Value tab, click New. Type ListBoxField for the name and click OK. In the Possible Values field, type Blue;Green;Red;Yellow, and then click OK.
 * 6) On the Form menu, click Run This Form.

Click the P.2 page of the form. You can then select any item in the list box and the selected value will be stored in the ListBoxField user-defined field.

NOTE: In step 5, instead of using a Text field, you can use a Keywords field to store the data for a list box (not a combo box). When a ListBox control is bound to a Keywords field, check boxes will appear next to the possible values in the list box and the user can make multiple selections. All of these selections are stored in the multi-value Keywords field. However, Keywords fields are limited to 255 characters, so this type of field should be used only if the user will be selecting from a relatively few possible values.

For more information about this limitation of the Keywords field, please see the following article in the Microsoft Knowledge Base:

196937 OL98: ListBox Bound to Keywords Field Unexpectedly Changes

Dynamically Populating List Boxes and Combo Boxes at Run-Time
Many solutions require that the possible values in a list box or combo box be up-to-date or refreshed regularly. The values are typically stored in some other location and need to be retrieved every time the item is opened. To accomplish this, you can add Visual Basic Scripting Edition (VBScript) code to the form and use an Item_Open event to run code whenever an item is opened. This code will fill the list box or combo box with possible values.

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There are various ways in which you can use VBScript to populate a list box or combo box.

PossibleValues Property
If you have a relatively simple list box or combo box to work with, you can automate the design-time steps by using the PossibleValues property of the control. This property is unique to Outlook and should be set to a semicolon-delimited string, just like the design-time steps earlier. To see how the PossibleValue property can be implemented, follow these steps:

 On the Tools menu, point to Forms, and then click Design a Form. In the Standard Forms Library, click Message, and then click Open. Click the (P.2) tab. On the Form menu, click Control Toolbox. On the Control Toolbox, drag a ListBox onto the form. Right-click the list box and then click Properties. On the Value tab, click New. Type ListBoxField2 for the name and click OK. Leave the Possible Values field blank and then click OK.  On the Form menu, click View Code. Enter the following VBScript code and then close the Script Editor. Sub Item_Open

' Sets the name of page on the form (P.2) Set FormPage = Item.GetInspector.ModifiedFormPages("P.2")

' Sets Control to a list box called ListBox1. Set Control = FormPage.Controls("ListBox1")

' Assign values to the list box. Control.PossibleValues = "Blue;Green;Red;Yellow"

End Sub </li> On the Form menu, click Run This Form.</li></ol>

Click the P.2 page of the form. You can then select any item in the list box and the selected value will be stored in the ListBoxField2 user-defined field.

AddItem Method
The AddItem method is typically used when you are looping through a series of data. As you loop through the data, you add items to the list box or combo box one at a time.

For an example of using the AddItem method to populate a combo box, please see the following article in the Microsoft Knowledge Base:

180911 OL98: How to Populate a Combo Box with Your Contacts

List Property
List boxes and combo boxes have a List property that allows you to specify an array which contains the data the control should use. If your programming solution is already using arrays to store data, using this approach can provide the simplest programming solution. Also, one key advantage to using the List property is that if you wish to populate the list box or combo box with multi-column data, the List property supports multi-dimensional arrays to accomplish this.

To populate a two-column list box with data from your Contacts folder, following these steps:

<ol> On the Tools menu, point to Forms, and then click Design a Form.</li> In the Standard Forms Library, click Message, and then click Open.</li> Click the (P.2) tab.</li> On the Form menu, click Control Toolbox. On the Control Toolbox, drag a ListBox onto the form. Make sure the list box is sized large enough to fill most of the form page.</li>  On the Form menu, click View Code. Enter the following VBScript code and then close the Script Editor. Sub Item_Open

Dim FullArray

' Sets the name of page on the form (P.2) Set FormPage = Item.GetInspector.ModifiedFormPages("P.2")

' Sets Control to a list box called ListBox1. Set Control = FormPage.Controls("ListBox1")

' Get the default Contacts folder Set ConFolder = Application.Session.GetDefaultFolder(10)

' Get the items in the folder Set ConItems = ConFolder.Items

' Get the number of total items in the Contacts folder NumItems = ConItems.Count

' Resize array to handle total number of item in the folder ReDim FullArray(NumItems-1,2)

' Loop through all of the items in the Contacts folder, ' filling the array with sample data and keeping track ' of the number of contacts found. NumContacts = 0 For I = 1 to NumItems Set itm = ConItems(I) If Left(itm.MessageClass, 11) = "IPM.Contact" Then NumContacts = NumContacts + 1 FullArray(NumContacts-1,1) = itm.FullName FullArray(NumContacts-1,2) = itm.CompanyName End If  Next

' Set the control to handle 2 data columns Control.ColumnCount = 3

If NumItems = NumContacts Then ' They are all contacts, so use the FullArray Control.List = FullArray Else ' There's some distribution lists, so use the smaller ' ConArray to eliminate extra blank values in the listbox Dim ConArray ReDim ConArray(NumContacts-1,2) For I = 0 to NumContacts - 1 ConArray(I,1) = FullArray(I,1) ConArray(I,2) = FullArray(I,2) Next Control.List = ConArray End If

End Sub </li> On the Form menu, click Run This Form.</li></ol>

Click the P.2 page of the form. The list box will be populated with the data from your default Contacts folder.

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