ConsoleKeyInfo.KeyChar Proprietà

Definizione

Spazio dei nomi:

System

Assembly:

System.Console.dll

Assembly:

mscorlib.dll

Assembly:

netstandard.dll

Ottiene il carattere Unicode rappresentato dall'oggetto ConsoleKeyInfo corrente.

public:
 property char KeyChar { char get(); };

public char KeyChar { get; }

member this.KeyChar : char

Public ReadOnly Property KeyChar As Char

Valore della proprietà

Char

Oggetto che corrisponde al tasto della console rappresentato dall'oggetto ConsoleKeyInfo corrente.

Esempio

Nell'esempio seguente viene usata la KeyChar proprietà per aggiungere l'input dei caratteri dall'utente in una stringa. Nell'esempio vengono ignorate chiavi speciali diverse da ENTER, ESC e BACKSPACE.

using System;

public class Example
{
   public static void Main()
   {
      // Configure console.
      Console.BufferWidth = 80;
      Console.WindowWidth = Console.BufferWidth;
      Console.TreatControlCAsInput = true;

      string inputString = String.Empty;
      ConsoleKeyInfo keyInfo;

      Console.WriteLine("Enter a string. Press <Enter> or Esc to exit.");
      do {
         keyInfo = Console.ReadKey(true);
         // Ignore if Alt or Ctrl is pressed.
         if ((keyInfo.Modifiers & ConsoleModifiers.Alt) == ConsoleModifiers.Alt)
            continue;
         if ((keyInfo.Modifiers & ConsoleModifiers.Control) == ConsoleModifiers.Control)
            continue;
         // Ignore if KeyChar value is \u0000.
         if (keyInfo.KeyChar == '\u0000') continue;
         // Ignore tab key.
         if (keyInfo.Key == ConsoleKey.Tab) continue;
         // Handle backspace.
         if (keyInfo.Key == ConsoleKey.Backspace) {
            // Are there any characters to erase?
            if (inputString.Length >= 1) {
               // Determine where we are in the console buffer.
               int cursorCol = Console.CursorLeft - 1;
               int oldLength = inputString.Length;
               int extraRows = oldLength / 80;

               inputString = inputString.Substring(0, oldLength - 1);
               Console.CursorLeft = 0;
               Console.CursorTop = Console.CursorTop - extraRows;
               Console.Write(inputString + new String(' ', oldLength - inputString.Length));
               Console.CursorLeft = cursorCol;
            }
            continue;
         }
         // Handle Escape key.
         if (keyInfo.Key == ConsoleKey.Escape) break;
         // Handle key by adding it to input string.
         Console.Write(keyInfo.KeyChar);
         inputString += keyInfo.KeyChar;
      } while (keyInfo.Key != ConsoleKey.Enter);
      Console.WriteLine("\n\nYou entered:\n    {0}",
                        String.IsNullOrEmpty(inputString) ? "<nothing>" : inputString);
   }
}

open System

// Configure console.
Console.TreatControlCAsInput <- true

printfn "Enter a string. Press <Enter> or Esc to exit."

let mutable inputString = String.Empty
let mutable keyInfo = Unchecked.defaultof<ConsoleKeyInfo>

while keyInfo.Key <> ConsoleKey.Enter && keyInfo.Key <> ConsoleKey.Escape do
    keyInfo <- Console.ReadKey true
    
    // Ignore if Alt or Ctrl is pressed.
    if keyInfo.Modifiers &&& ConsoleModifiers.Alt <> ConsoleModifiers.Alt &&
       keyInfo.Modifiers &&& ConsoleModifiers.Control <> ConsoleModifiers.Control &&
       // Ignore if KeyChar value is \u0000.
       keyInfo.KeyChar <> '\u0000' &&
       // Ignore tab key.
       keyInfo.Key <> ConsoleKey.Tab then
        
        // Handle backspace.
        if keyInfo.Key = ConsoleKey.Backspace then
            // Are there any characters to erase?
            if inputString.Length >= 1 then
                // Determine where we are in the console buffer.
                let cursorCol = Console.CursorLeft - 1
                let oldLength = inputString.Length
                let extraRows = oldLength / 80

                inputString <- inputString.Substring(0, oldLength - 1)
                Console.CursorLeft <- 0
                Console.CursorTop <- Console.CursorTop - extraRows
                printf $"{inputString + String(' ', oldLength - inputString.Length)}"
                Console.CursorLeft <- cursorCol
        else
            // Handle key by adding it to input string.
            printf $"{keyInfo.KeyChar}"
            inputString <- inputString + string keyInfo.KeyChar
    
printfn $"""

You entered:
    {if String.IsNullOrEmpty inputString then "<nothing>" else inputString}"""

Module Example
   Public Sub Main()
      ' Configure console.
      Console.BufferWidth = 80
      Console.WindowWidth = Console.BufferWidth
      Console.TreatControlCAsInput = True
      
      Dim inputString As String = String.Empty
      Dim keyInfo As ConsoleKeyInfo

      Console.WriteLine("Enter a string. Press <Enter> or Esc to exit.")
      Do
         keyInfo = Console.ReadKey(True)
         ' Ignore if Alt or Ctrl is pressed.
         If (keyInfo.Modifiers And ConsoleModifiers.Alt) = ConsoleModifiers.Alt _
                              Then Continue Do 
         If (keyInfo.Modifiers And ConsoleModifiers.Control) = ConsoleModifiers.Control _
                              Then Continue Do 
         ' Ignore if KeyChar value is \u0000.
         If keyInfo.KeyChar = ChrW(0) Then Continue Do
         ' Ignore tab, clear key.
         If keyInfo.Key = ConsoleKey.Tab Then Continue Do
         ' Handle backspace.
         If keyInfo.Key = ConsoleKey.Backspace Then
            ' Are there any characters to erase?
            If inputString.Length >= 1 Then
               ' Determine where we are in the console buffer.
               Dim cursorCol As Integer = Console.CursorLeft - 1
               Dim oldLength As Integer = inputString.Length
               Dim extraRows As Integer = oldLength \ 80

               inputString = inputString.Substring(0, oldLength - 1)
               Console.CursorLeft = 0
               Console.CursorTop = Console.CursorTop - extraRows
               Console.Write(inputString + New String(" "c, oldLength - inputString.Length))
               Console.CursorLeft = cursorCol
            End If
            Continue Do
         End If   
         ' Handle Escape key.
         If keyInfo.Key = ConsoleKey.Escape Then Exit Do
         ' Handle key by adding it to input string.
         Console.Write(keyInfo.KeyChar)
         inputString += keyInfo.KeyChar 
      Loop While keyInfo.Key <> ConsoleKey.Enter
      Console.WriteLine("{0}{0}You entered:{0}    {1}", vbCrLf, _
                        IIf(String.IsNullOrEmpty(inputString), "<nothing>", inputString))
   End Sub
End Module

Commenti

Se il tasto premuto non esegue il mapping a un carattere Unicode, ad esempio se l'utente preme il tasto F1 o il tasto Home , il valore della KeyChar proprietà è \U0000.