如何从Xamarin中的Picker Length计算值

Picker picker = new Picker
{
    Title = "Select a Length",
    ItemsSource = new List<string> { "1 inch", "1 foot", "1 yard" },
    SelectedIndexChanged += (sender, args) =>
    {
        // 在这里进行计算值的逻辑
        string selectedItem = picker.SelectedItem.ToString();
        // 根据选中项计算值
        double value = CalculateLength(selectedItem);
        // 进行后续操作，例如更新UI或发送网络请求
    }
};

private double CalculateLength(string selectedItem)
{
    double value = 0;
    if (selectedItem.Contains("inch"))
    {
        // 根据选中项中包含的英寸数进行计算
        string inchesString = selectedItem.Substring(0, selectedItem.IndexOf(" inch"));
        double inches = Convert.ToDouble(inchesString);
        value = inches * 2.54; // 英寸转换为厘米
    }
    else if (selectedItem.Contains("foot"))
    {
        // 根据选中项中包含的英尺数进行计算
        string feetString = selectedItem.Substring(0, selectedItem.IndexOf(" foot"));
        double feet = Convert.ToDouble(feetString);
        value = feet * 30.48; // 英尺转换为厘米
    }
    else if (selectedItem.Contains("yard"))
    {
        // 根据选中项中包含的码数进行计算
        string yardsString = selectedItem.Substring(0, selectedItem.IndexOf(" yard"));
        double yards = Convert.ToDouble(yardsString);
        value = yards * 91.44; // 码转换为厘米
    }
    return value;
}