Controls - Do you include '-All-' option in your ComboBoxes?

ComboBoxes are often used for filtering data. It is best to have an '-All-' option to give your user chances to select all data.

It is important to understand the idea of visual text . In a list you could see either:

• -None- or
• No activity assigned

They both have the same meaning, but the first one is immediately visible whereas the second one must be read. If the ID column in your database is a string data type, it is useful to add a constraint to limit the types of characters that it can contain. Adding a constraint can make it simpler to build your front-end, as you won't need to worry about encoding or escaping to handle special characters.

In SQL Server, you can add a check constraint that limits your column to alphanumeric characters, a hyphen, or underscore using the following T-SQL:

ALTER TABLE [TableName] ADD CONSTRAINT CK_String_Identifier
    CHECK ([StringIdColumn] NOT LIKE'%[^a-zA-Z0-9_\-]%')

❌ Figure: Bad example - No '-All-' option so the user cannot select all data

✅ Figure: Good example - Having an '-All-' option gives a user a chance to select all data

Also, keep it simple!

❌ Figure: Bad example - '-All Stores-' isn't needed

✅ Figure: Good example - Keep it as a simple '-All-'

✅ Figure: Good example - Keeping it simple makes it easy to spot (that there is no filter) when you have multiple fields.

Read our rule on Always make sure the dimensions All Captions = All.