如何在带有UItextfield的xamarin IOS中只设置向前和向后文本框焦点？

public partial class YourViewController : UIViewController, IUITextFieldDelegate
{
    public override void ViewDidLoad()
    {
        base.ViewDidLoad();

        // 设置UITextField的代理
        yourTextField.Delegate = this;
    }

    // 实现UITextFieldDelegate中的ShouldReturn方法
    [Export("textFieldShouldReturn:")]
    public bool ShouldReturn(UITextField textField)
    {
        // 当用户点击Return键时，向前切换到上一个文本框
        if (textField == yourTextField)
        {
            previousTextField.BecomeFirstResponder();
        }
        // 当用户点击Next键时，向后切换到下一个文本框
        else if (textField == previousTextField)
        {
            nextTextField.BecomeFirstResponder();
        }

        return true;
    }
}