Question

When I add the value from database, the listbox should avoid the duplicate value.

For Example

List1 box

 Value

100
200'
300

From the table, when i add the same value 001, the listbox should avoid the value. When I try to add 400, the listbox should allow to add.

Answer 1

When you create your listbox, you should use a dictionary to store all these values.

Then, you can check if the value exists:

If Not dict.Exists(key) Then 
    dict.Add key, value
    listitem.Add key
End If 

See this thread for more information: Does VBA have Dictionary Structure?