public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value)
{
if (null == provider)
{
Debug.Assert(false, "NoneOptionListBoxTypeEditor.EditValue(): provider object must not be null");
// returning value means "no change"
return(value);
}
else
{
_editorService =
provider.GetService(typeof(IWindowsFormsEditorService)) as IWindowsFormsEditorService;
Debug.Assert(null != _editorService, "Could not find IWindowsFormsEditorService for provider " + provider);
if (null != _editorService)
{
// create and populate the list-box
using (var listBox = new NoneOptionListBox())
{
// if the (None) value was the incoming value then show this by pre-selecting that
// value in the list, otherwise leave all items unselected
if (StringOrNone.NoneValue.Equals(value))
{
listBox.SelectedIndex = 0;
}
// now set up the SelectedValueChanged event handler
listBox.SelectedValueChanged += listBox_SelectedValueChanged;
// display the list-box and let user choose
_editorService.DropDownControl(listBox);
var selectedItem = listBox.SelectedItem as string;
Debug.Assert(
null == selectedItem ||
Resources.NoneDisplayValueUsedForUX.Equals(selectedItem, StringComparison.CurrentCulture),
typeof(NoneOptionListBox).Name + ": selectedItem should be null or NoneObject");
// desubscribe from the SelectedValueChanged event handler
listBox.SelectedValueChanged -= listBox_SelectedValueChanged;
// return value dependent on what user chose
if (Resources.NoneDisplayValueUsedForUX.Equals(selectedItem, StringComparison.CurrentCulture))
{
value = StringOrNone.NoneValue;
}
else
{
// user did not select the None option - return null indicating no selection
value = null;
}
}
}
}
return(value);
}
public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value)
{
if (null == provider)
{
Debug.Assert(false, "NoneOptionListBoxTypeEditor.EditValue(): provider object must not be null");
// returning value means "no change"
return value;
}
else
{
_editorService =
provider.GetService(typeof(IWindowsFormsEditorService)) as IWindowsFormsEditorService;
Debug.Assert(null != _editorService, "Could not find IWindowsFormsEditorService for provider " + provider);
if (null != _editorService)
{
// create and populate the list-box
using (var listBox = new NoneOptionListBox())
{
// if the (None) value was the incoming value then show this by pre-selecting that
// value in the list, otherwise leave all items unselected
if (StringOrNone.NoneValue.Equals(value))
{
listBox.SelectedIndex = 0;
}
// now set up the SelectedValueChanged event handler
listBox.SelectedValueChanged += listBox_SelectedValueChanged;
// display the list-box and let user choose
_editorService.DropDownControl(listBox);
var selectedItem = listBox.SelectedItem as string;
Debug.Assert(
null == selectedItem
|| Resources.NoneDisplayValueUsedForUX.Equals(selectedItem, StringComparison.CurrentCulture),
typeof(NoneOptionListBox).Name + ": selectedItem should be null or NoneObject");
// desubscribe from the SelectedValueChanged event handler
listBox.SelectedValueChanged -= listBox_SelectedValueChanged;
// return value dependent on what user chose
if (Resources.NoneDisplayValueUsedForUX.Equals(selectedItem, StringComparison.CurrentCulture))
{
value = StringOrNone.NoneValue;
}
else
{
// user did not select the None option - return null indicating no selection
value = null;
}
}
}
}
return value;
}
