InfoPath - Filtering Values based on Drop Down Selection.

Below is a small Infopath solution I came across today when developing a dynamic InfoPath form.

How to select an item from a dropdown list box, retrieve the database record corresponding to the item, and display the data in fields:

You can do this using a combination of default data, formulas, and filters (available in SP1).
Do the following:
1. Open the properties dialog for the TextBox by double-clicking in the control in the view.

2. Click on the Fx button next to the value field

3. Click the Insert a Field or Group button

4. Choose the correct field for the text box from the secondary data source

5. Click the filter button

6. Click add

7. From the left-most dropdown choose the " drop down list " field from the secondary data source

8. Leave the middle dropdown as "is equal to"

9. Open the right-most dropdown and choose "Select a field or group"

10. Choose the "drop down list" field from the main data source

11. Close all the dialogs

Now, when you preview or open the form and choose a name from the dropdown the gender will display in the textbox.