Unfortunately, the IF function itself cannot directly control data validation rules within Excel. Data validation rules are pre-set limitations on what kind of data a user can enter into a cell. However, you can achieve a similar effect by combining the IF function with other conditional formatting techniques.

Here's a workaround using conditional formatting based on the IF function:

Scenario: Let's say you want to restrict data entry in cells B2:B10 based on a value in cell A1. If A1 contains "Fruit," then allow users to enter only text values (like apple, banana) in B2:B10. If A1 contains anything else, allow both text and numbers in B2:B10.

1. Select the range for conditional formatting: Highlight cells B2:B10 where you want to conditionally restrict data entry.
2. Go to Conditional Formatting: Navigate to the "Home" tab and click on "Conditional Formatting" in the Styles group.
3. Use a formula to determine which cells to format: Choose this option from the dropdown menu.
4. Enter the IF formula: In the formula bar, enter the following formula:

```excel
=IF(A1="Fruit",A1="Text",TRUE)
```

Explanation:

- The IF function checks the value in cell A1.
- If A1 contains "Fruit" (text enclosed in double quotes), the formula evaluates to "Text" (also in quotes). This essentially creates a text format condition.
- If A1 contains anything else, the formula evaluates to TRUE. This acts as a catch-all, allowing any type of data entry (both text and numbers).

5. Formatting (Optional): You can set a specific format for text entries (e.g., font color) to visually differentiate when the "Fruit" restriction is applied. Click on the "Format" button and choose your desired formatting options.
6. Click OK: Click "OK" to apply the conditional formatting rule.

Now, when the value in A1 changes, the conditional formatting based on the IF function will automatically adjust the allowed data types in B2:B10. If A1 is "Fruit," only text will be allowed. Otherwise, any data type (text or numbers) will be accepted.

Note: This is just one example. You can modify the IF function's logic and conditional formatting settings to achieve different data validation scenarios based on your specific needs.