How to: Set the Selection in List Web Server Controls
The information in this topic applies to these Web server controls:
Normally, users select items in a list Web server control to indicate their choice. However, you might want to pre-select items or select items at run time (programmatically) based on some condition.
To set the selection in a list Web server control at design time
-
In the Properties window, click the ellipsis button (
) for the Items property to open the ListItem Collection Editor dialog box. -
From the Members list, choose the member to be selected, and then set its Selected property to true.
-
If the control is set to allow multiple selections, repeat step 2 for each item to select, and then click OK to close the dialog box.
To set a single selection in a list Web server control programmatically
-
Do one of the following:
-
Set the control's SelectedIndex property to the index value of the item to select. The index is zero-based. To set no selection, set SelectedIndex to -1.
Note
If you set the SelectedIndex property of a DropDownList control to -1, the control resets the value to 0, because the DropDownList control always has a list item selected.
-
Set the Selected property of an individual item in the list.
-
To set multiple selections in a list control programmatically
-
Loop through the control's Items collection and set the Selected property of every individual item.
Note
You can only select multiple items if the control's SelectionMode property is set to Multiple.
The following example shows how you can set selections in a multi-selection ListBox control called ListBox1. The code selects every other item.