c# - 如果输入命令，如何在保留旧文本的同时添加新文本？

Question

我基本上是在尝试保留旧文本，而如果您输入帮助，它会添加一行新文本。问题是每次我输入帮助时，它都会再次(两次)打印旧文本，然后打印新文本。

     public Canvas myCanvas;
     public Text myText;

     private string display = "";

     List<string> chatEvents;

     private bool calltext;

     public InputField inputfield;
     private Dictionary<string, System.Action<string,string>> commands;

     protected void Awake()
     {
         commands = new Dictionary<string, System.Action<string,string>>();
         // Add the commands you want to recognise along with the functions to call
         commands.Add( "help", OnHelpTyped );
         // Listen when the inputfield is validated
         inputfield.onEndEdit.AddListener( OnEndEdit );
     }

     private void OnEndEdit( string input )
     {
         // Only consider onEndEdit if the Submit button has been pressed
         if ( !Input.GetButtonDown( "Submit" ) )
             return;

         bool commandFound = false;

         // Find the command
         foreach ( var item in commands )
         {
             if ( item.Key.ToLower().StartsWith( input.ToLower() ) )
             {
                 commandFound = true;
                 item.Value( item.Key, input );
                 break;
             }
         }

         // Do something if the command has not been found
         if ( !commandFound )
             Debug.Log( "No word found" );

         // Clear the input field (if you want)
         inputfield.text = "";
     }

     private void OnHelpTyped( string command, string input )
     {
         chatEvents.Add ("The List");
         calltext = true;
     }

     // Use this for initialization
     void Start () {
         chatEvents = new List<string>();

         chatEvents.Add("Welcome to my simple application ");
         chatEvents.Add ("Type help for list of commands");

         calltext = true;

     }

     // Update is called once per frame
     void Update () {
         if(calltext)
         {
             AddText();
             calltext = false;
         }
     }

     void AddText()
     {
         foreach(string msg in chatEvents)
         {
             display = display.ToString () + msg.ToString() + "\n";
         }
         myText.text = display;
     }
 }

这是前后对比图

Image 1

Image 2

Answer 1

您似乎从未清除过chatEvents 列表，因此每次您调用AddText 时，您都会遍历chatEvents 中的所有字符串并添加它们再次。