无法获取IF语句以从ComboBox Selection C#更新TextBlock

Question

我试图返回到主程序，但它必须在ComboBox更改时更改。无论它返回的是什么，无论在类的顶部将字符串设置为什么。如果我将% the result = ""；更改为% result = "Test"；，它将在我试图更新的TextBox中显示Test。但是它不会从IF语句中得到任何东西。

谢谢你的帮助！

主程序

namespace VTCPT
{
    /// <summary>
    /// 
    /// </summary>
    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();


        }

        private void ComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
              //UPDATE THE SHORTCODE TEXTBLOCK
            updateVTCShortCode display = new updateVTCShortCode();
            display.mergeShortCode(longFormCodec.SelectedItem.ToString());
            if (String.IsNullOrEmpty(display.finalResult()))
                { shortFormCodec.Text = ".."; }
            else { shortFormCodec.Text = display.finalResult(); }
            }

        private void updateShortForm(object sender, SelectionChangedEventArgs e)
        {

        }


        private void TextBlock_SelectionChanged(object sender, RoutedEventArgs e)
        {


        }

        private void fsSiteBuild_SelectionChanged(object sender, RoutedEventArgs e)
        {
        }


        private void updateSiteBuild(object sender, TextChangedEventArgs e)
        {
            int index = fsRoomDesig.Text.IndexOf(".");

            if (index > 0)
            { fsSiteBuild.Text = fsRoomDesig.Text.Substring(0, index); }
            else { fsSiteBuild.Text = ".."; }
        }

        private void vtcSystemName_SelectionChanged(object sender, RoutedEventArgs e)
        {

        }     
    }
}

updateVTCShortCode类

namespace VTCPT
{
    class updateVTCShortCode
    {
        String result = "";  //////ALWAYS RESULTS ONLY IN WHAT IS HERE
        public void mergeShortCode(String longFormCodec)
         {

            if (longFormCodec == "Cisco SX80")
            {
                String sendShortForm = "SX80";
                result = "V-T" + sendShortForm;

            }
            if (longFormCodec == "Cisco Webex Codec Plus")
            {
                String sendShortForm = "SRK";
                result = "V-T" + sendShortForm;
            }
            if (longFormCodec == "Cisco Webex Codec Pro")
            {
                String sendShortForm = "SRK";
                result = "V-T" + sendShortForm;
            }
    }
        public String finalResult()
        { return result; }
    }
}

Answer 1

您没有正确地进行字符串比较。对于字符串，您需要使用.equals()。

您需要将使用==的所有字符串比较替换为.equals()，它将起作用：

namespace VTCPT
{
    class updateVTCShortCode
    {
        String result = "";  //////ALWAYS RESULTS ONLY IN WHAT IS HERE
        public void mergeShortCode(String longFormCodec)
         {

            if (longFormCodec.equals("Cisco SX80"))
            {
                String sendShortForm = "SX80";
                result = "V-T" + sendShortForm;

            }
            if (longFormCodec.equals("Cisco Webex Codec Plus"))
            {
                String sendShortForm = "SRK";
                result = "V-T" + sendShortForm;
            }
            if (longFormCodec.equals("Cisco Webex Codec Pro"))
            {
                String sendShortForm = "SRK";
                result = "V-T" + sendShortForm;
            }
    }
        public String finalResult()
        { return result; }
    }
}