ComboBox.SelectedIndex Property

This property indicates the zero-based index of the currently selected item in the combo box list. Setting a new index raises the SelectedIndexChanged event.

SelectedIndex, SelectedValue, and FormattingEnabled are related as follows:

• If FormattingEnabled is false, SelectedIndex will not be set to -1 when SelectedValue is blank.

• If FormattingEnabled is true, SelectedIndex will be set to -1 when SelectedValue is blank.

Note
To deselect the currently selected item, set the SelectedIndex to -1. You cannot set the SelectedIndex of a ComboBox item to -1 if the item is a data-bound item.

The following code example show how to use the FindString method and SelectedIndex property. The example is part of a complete example in the ComboBox class overview.

private void findButton_Click(object sender, System.EventArgs e) {
    int index = comboBox1.FindString(textBox2.Text);
    comboBox1.SelectedIndex = index;
}

.NET Framework

.NET Framework Client Profile

Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Reference