Nullable ComboBox

[itg-assistant]

Bernhard Lang asked 2018-01-11 14:54:16 UTC

Hello,

it would be nice if it would be possible to have a Nullable ComboBox. Maybe enabled by a Property. If you set a DataSource it will automatically add a null option in the DropDown. As an additional property a NullValueText would be nice so we show different text like “”, “(none)” or “(empty)”.

best regards

Bernhard

[itg-assistant]

Luca answered 2018-01-11 16:45:19 UTC

When the ComboBox is DataBound you can set SelectedIndex to -1, make sure that the combobox1.FormattingEnable property is true.

[itg-assistant]

Bernhard Lang answered 2018-01-12 06:43:46 UTC

Thank you for your reply.

With this solution it is not possible for the user to select null in the dropdown or am I missing something?

[itg-assistant]

Luca answered 2018-01-12 18:30:45 UTC

The data binder position is in sync with the SelectedIndex unless it's -1. We can't add an item 0 and make it act as -1, it would create too may potential problems.

You can also add a tool button to the ComboBox to set it to "null", SelectedIndex = -1. See screenshot attached. Most controls in Wisej have the Tools property.

The Watermark text is shown when nothing is selected when the combo is editable.