form.cshtml

    <form method="POST" asp-action="Administration">            
        <ul>
            <li>
                <input type="text" name="DepartmentId[]" value="foo"/>
                <select name="CompanyNumber[]">
                    <option value="foo">foo</option>
                    <option value="bar">bar</option>
                    <option value="baz">baz</option>
                </select>
            </li>
            
            <li>
                <input type="text" name="DepartmentId[]" value="bar"/>
                <select name="CompanyNumber[]">
                    <option value="foo">foo</option>
                    <option value="bar">bar</option>
                    <option value="baz">baz</option>
                </select>
            </li>
            
            <li>
                <input type="text" name="DepartmentId[]" value="baz"/>
                <select name="CompanyNumber[]">
                    <option value="foo">foo</option>
                    <option value="bar">bar</option>
                    <option value="baz">baz</option>
                </select>
            </li>
        </ul>

        <input type="submit" value="Save"/>
    </form>