ComboBox.SelectedText doesn't give me the SelectedText

I think you want to use

String status = "The status of my combobox is " + comboBoxTest.Text

SelectedText property from MSDN

Gets or sets the text that is selected in the editable portion of a ComboBox.

while Text property from MSDN

Gets or sets the text associated with this control.

From the documentation:

You can use the SelectedText property to retrieve or change the currently selected text in a ComboBox control. However, you should be aware that the selection can change automatically because of user interaction. For example, if you retrieve the SelectedText value in a button Click event handler, the value will be an empty string. This is because the selection is automatically cleared when the input focus moves from the combo box to the button.

When the combo box loses focus, the selection point moves to the beginning of the text and any selected text becomes unselected. In this case, getting the SelectedText property retrieves an empty string, and setting the SelectedText property adds the specified value to the beginning of the text.

I think you dont need SelectedText but you may need

String status = "The status of my combobox is " + comboBoxTest.Text;