Console.Clear Methode

Referenz

Definition

Namespace:: System

Assembly:: System.Console.dll

Assembly:: netstandard.dll

Assembly:: mscorlib.dll

Wichtig

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public:
 static void Clear();

public static void Clear ();

[System.Runtime.Versioning.UnsupportedOSPlatform("android")]
[System.Runtime.Versioning.UnsupportedOSPlatform("ios")]
[System.Runtime.Versioning.UnsupportedOSPlatform("tvos")]
public static void Clear ();

static member Clear : unit -> unit

[<System.Runtime.Versioning.UnsupportedOSPlatform("android")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("ios")>]
[<System.Runtime.Versioning.UnsupportedOSPlatform("tvos")>]
static member Clear : unit -> unit

Public Shared Sub Clear ()

Attribute: UnsupportedOSPlatformAttribute

Ausnahmen

IOException

E/A-Fehler

Beispiele

Im folgenden Beispiel wird die -Methode verwendet, um die Konsole zu löschen, bevor eine -Schleife ausgeführt wird. Der Benutzer wird aufgefordert, eine Vordergrund- und Hintergrundfarbe auszuwählen und eine anzuzeigende Clear Zeichenfolge eingibt. Wenn der Benutzer das Programm nicht beendet, werden die ursprünglichen Vordergrund- und Hintergrundfarben der Konsole wiederhergestellt, und die -Methode wird erneut aufgerufen, bevor die Schleife Clear erneut ausgeführt wird.

using System;

public class Example
{
   public static void Main()
   {
      // Save colors so they can be restored when use finishes input.
      ConsoleColor dftForeColor = Console.ForegroundColor;
      ConsoleColor dftBackColor = Console.BackgroundColor;
      bool continueFlag = true;
      Console.Clear();

      do {
         ConsoleColor newForeColor = ConsoleColor.White;
         ConsoleColor newBackColor = ConsoleColor.Black;

         Char foreColorSelection = GetKeyPress("Select Text Color (B for Blue, R for Red, Y for Yellow): ",
                                              new Char[] { 'B', 'R', 'Y' } );
         switch (foreColorSelection) {
            case 'B':
            case 'b':
               newForeColor = ConsoleColor.DarkBlue;
               break;
            case 'R':
            case 'r':
               newForeColor = ConsoleColor.DarkRed;
               break;
            case 'Y':
            case 'y':
               newForeColor = ConsoleColor.DarkYellow;
               break;
         }
         Char backColorSelection = GetKeyPress("Select Background Color (W for White, G for Green, M for Magenta): ",
                                              new Char[] { 'W', 'G', 'M' });
         switch (backColorSelection) {
            case 'W':
            case 'w':
               newBackColor = ConsoleColor.White;
               break;
            case 'G':
            case 'g':
               newBackColor = ConsoleColor.Green;
               break;
            case 'M':
            case 'm':
               newBackColor = ConsoleColor.Magenta;
               break;
         }

         Console.WriteLine();
         Console.Write("Enter a message to display: ");
         String textToDisplay = Console.ReadLine();
         Console.WriteLine();
         Console.ForegroundColor = newForeColor;
         Console.BackgroundColor = newBackColor;
         Console.WriteLine(textToDisplay);
         Console.WriteLine();
         if (Char.ToUpper(GetKeyPress("Display another message (Y/N): ", new Char[] { 'Y', 'N' } )) == 'N')
            continueFlag = false;

         // Restore the default settings and clear the screen.
         Console.ForegroundColor = dftForeColor;
         Console.BackgroundColor = dftBackColor;
         Console.Clear();
      } while (continueFlag);
   }

   private static Char GetKeyPress(String msg, Char[] validChars)
   {
      ConsoleKeyInfo keyPressed;
      bool valid = false;

      Console.WriteLine();
      do {
         Console.Write(msg);
         keyPressed = Console.ReadKey();
         Console.WriteLine();
         if (Array.Exists(validChars, ch => ch.Equals(Char.ToUpper(keyPressed.KeyChar))))
            valid = true;
      } while (! valid);
      return keyPressed.KeyChar;
   }
}

open System

let getKeyPress msg validChars =
    Console.WriteLine()
    
    let mutable valid = false
    let mutable keyChar = ' '
    
    while not valid do
        printfn "%s" msg
        let keyPressed = Console.ReadKey()
        printfn ""
        if validChars |> List.exists (fun ch -> ch.Equals(Char.ToUpper keyPressed.KeyChar)) then
            valid <- true
            keyChar <- keyPressed.KeyChar
    keyChar

// Save colors so they can be restored when use finishes input.
let dftForeColor = Console.ForegroundColor
let dftBackColor = Console.BackgroundColor
let mutable continueFlag = true
Console.Clear()

while continueFlag do
    let foreColorSelection = 
        getKeyPress "Select Text Color (B for Blue, R for Red, Y for Yellow): " [ 'B'; 'R'; 'Y' ]
    
    let newForeColor = 
        match foreColorSelection with
        | 'B' | 'b' ->
            ConsoleColor.DarkBlue
        | 'R' | 'r' ->
            ConsoleColor.DarkRed
        | 'Y' | 'y' ->
            ConsoleColor.DarkYellow
        | _ -> ConsoleColor.White

    let backColorSelection = 
        getKeyPress "Select Background Color (W for White, G for Green, M for Magenta): " [ 'W'; 'G'; 'M' ]

    let newBackColor = 
        match backColorSelection with
        | 'W' | 'w' ->
            ConsoleColor.White
        | 'G' | 'g' ->
            ConsoleColor.Green
        | 'M' | 'm' ->
            ConsoleColor.Magenta
        | _ -> ConsoleColor.Black

    printfn ""
    printf "Enter a message to display: "
    let textToDisplay = Console.ReadLine()
    printfn ""
    Console.ForegroundColor <- newForeColor
    Console.BackgroundColor <- newBackColor
    printfn "%s" textToDisplay
    printfn ""
    if Char.ToUpper(getKeyPress "Display another message (Y/N): " [ 'Y'; 'N' ] ) = 'N' then
        continueFlag <- false

    // Restore the default settings and clear the screen.
    Console.ForegroundColor <- dftForeColor
    Console.BackgroundColor <- dftBackColor
    Console.Clear()

Module Example
   Public Sub Main()
      ' Save colors so they can be restored when use finishes input.
      Dim dftForeColor As ConsoleColor = Console.ForegroundColor
      Dim dftBackColor As ConsoleColor = Console.BackgroundColor
      Dim continueFlag As Boolean = True
      Console.Clear()
            
      Do 
         Dim newForeColor As ConsoleColor
         Dim newBackColor As ConsoleColor
                  
         Dim foreColorSelection As Char = GetKeyPress("Select Text Color (B for Blue, R for Red, Y for Yellow): ", 
                                              { "B"c, "R"c, "Y"c } )
         Select Case foreColorSelection
            Case "B"c, "b"c
               newForeColor = ConsoleColor.DarkBlue
            Case "R"c, "r"c
               newForeColor = ConsoleColor.DarkRed
            Case "Y"c, "y"c
               newForeColor = ConsoleColor.DarkYellow   
         End Select
         Dim backColorSelection As Char = GetKeyPress("Select Background Color (W for White, G for Green, M for Magenta): ",
                                              { "W"c, "G"c, "M"c })
         Select Case backColorSelection
            Case "W"c, "w"c
               newBackColor = ConsoleColor.White
            Case "G"c, "g"c
               newBackColor = ConsoleColor.Green
            Case "M"c, "m"c
               newBackColor = ConsoleColor.Magenta   
         End Select
         
         Console.WriteLine()
         Console.Write("Enter a message to display: ")
         Dim textToDisplay As String = Console.ReadLine()
         Console.WriteLine()
         Console.ForegroundColor = newForeColor
         Console.BackgroundColor = newBackColor
         Console.WriteLine(textToDisplay)
         Console.WriteLine()
         If Char.ToUpper(GetKeyPress("Display another message (Y/N): ", { "Y"c, "N"c } )) = "N" Then
            continueFlag = False
         End If
         ' Restore the default settings and clear the screen.
         Console.ForegroundColor = dftForeColor
         Console.BackgroundColor = dftBackColor
         Console.Clear()
      Loop While continueFlag
   End Sub
   
   Private Function GetKeyPress(msg As String, validChars() As Char) As Char
      Dim keyPressed As ConsoleKeyInfo
      Dim valid As Boolean = False
      
      Console.WriteLine()
      Do
         Console.Write(msg)
         keyPressed = Console.ReadKey()
         Console.WriteLine()
         If Array.Exists(validChars, Function(ch As Char) ch.Equals(Char.ToUpper(keypressed.KeyChar)))           
            valid = True
         End If
      Loop While Not valid
      Return keyPressed.KeyChar 
   End Function
End Module

Das Beispiel basiert auf einer -Methode, um die Auswahl einer Vordergrund- und Hintergrundfarbe durch den GetKeyPress Benutzer zu überprüfen.

In diesem Beispiel werden die CursorLeft Eigenschaften und sowie die Methoden und CursorTop SetCursorPosition Clear veranschaulicht. Im Beispiel wird der Cursor positioniert, der bestimmt, wo der nächste Schreibzugriff erfolgt, um ein Rechteck mit 5 Zeichen und 5 Zeichen zu zeichnen, indem eine Kombination aus Zeichenfolgen "+", "|" und "-" verwendet wird. Beachten Sie, dass das Rechteck mit einer Kombination aus anderen Zeichenfolgen mit weniger Schritten gezeichnet werden kann.

// This example demonstrates the 
//     Console.CursorLeft and 
//     Console.CursorTop properties, and the
//     Console.SetCursorPosition and 
//     Console.Clear methods.
using namespace System;
int origRow;
int origCol;
void WriteAt( String^ s, int x, int y )
{
   try
   {
      Console::SetCursorPosition( origCol + x, origRow + y );
      Console::Write( s );
   }
   catch ( ArgumentOutOfRangeException^ e ) 
   {
      Console::Clear();
      Console::WriteLine( e->Message );
   }

}

int main()
{
   
   // Clear the screen, then save the top and left coordinates.
   Console::Clear();
   origRow = Console::CursorTop;
   origCol = Console::CursorLeft;
   
   // Draw the left side of a 5x5 rectangle, from top to bottom.
   WriteAt( "+", 0, 0 );
   WriteAt( "|", 0, 1 );
   WriteAt( "|", 0, 2 );
   WriteAt( "|", 0, 3 );
   WriteAt( "+", 0, 4 );
   
   // Draw the bottom side, from left to right.
   WriteAt( "-", 1, 4 ); // shortcut: WriteAt("---", 1, 4)
   WriteAt( "-", 2, 4 ); // ...
   WriteAt( "-", 3, 4 ); // ...
   WriteAt( "+", 4, 4 );
   
   // Draw the right side, from bottom to top.
   WriteAt( "|", 4, 3 );
   WriteAt( "|", 4, 2 );
   WriteAt( "|", 4, 1 );
   WriteAt( "+", 4, 0 );
   
   // Draw the top side, from right to left.
   WriteAt( "-", 3, 0 ); // shortcut: WriteAt("---", 1, 0)
   WriteAt( "-", 2, 0 ); // ...
   WriteAt( "-", 1, 0 ); // ...
   
   //
   WriteAt( "All done!", 0, 6 );
   Console::WriteLine();
}

/*
This example produces the following results:

+---+
|   |
|   |
|   |
+---+

All done!

*/

// This example demonstrates the
//     Console.CursorLeft and
//     Console.CursorTop properties, and the
//     Console.SetCursorPosition and
//     Console.Clear methods.
using System;

class Sample
{
    protected static int origRow;
    protected static int origCol;

    protected static void WriteAt(string s, int x, int y)
    {
    try
        {
        Console.SetCursorPosition(origCol+x, origRow+y);
        Console.Write(s);
        }
    catch (ArgumentOutOfRangeException e)
        {
        Console.Clear();
        Console.WriteLine(e.Message);
        }
    }

    public static void Main()
    {
// Clear the screen, then save the top and left coordinates.
    Console.Clear();
    origRow = Console.CursorTop;
    origCol = Console.CursorLeft;

// Draw the left side of a 5x5 rectangle, from top to bottom.
    WriteAt("+", 0, 0);
    WriteAt("|", 0, 1);
    WriteAt("|", 0, 2);
    WriteAt("|", 0, 3);
    WriteAt("+", 0, 4);

// Draw the bottom side, from left to right.
    WriteAt("-", 1, 4); // shortcut: WriteAt("---", 1, 4)
    WriteAt("-", 2, 4); // ...
    WriteAt("-", 3, 4); // ...
    WriteAt("+", 4, 4);

// Draw the right side, from bottom to top.
    WriteAt("|", 4, 3);
    WriteAt("|", 4, 2);
    WriteAt("|", 4, 1);
    WriteAt("+", 4, 0);

// Draw the top side, from right to left.
    WriteAt("-", 3, 0); // shortcut: WriteAt("---", 1, 0)
    WriteAt("-", 2, 0); // ...
    WriteAt("-", 1, 0); // ...
//
    WriteAt("All done!", 0, 6);
    Console.WriteLine();
    }
}
/*
This example produces the following results:

+---+
|   |
|   |
|   |
+---+

All done!

*/

// This example demonstrates the
//     Console.CursorLeft and
//     Console.CursorTop properties, and the
//     Console.SetCursorPosition and
//     Console.Clear methods.
open System

// Clear the screen, then save the top and left coordinates.
Console.Clear()
let origRow = Console.CursorTop
let origCol = Console.CursorLeft

let writeAt s x y =
    try
        Console.SetCursorPosition(origCol + x, origRow + y)
        printfn $"%s{s}"
    with :? ArgumentOutOfRangeException as e ->
        Console.Clear()
        printfn $"{e.Message}"

// Draw the left side of a 5x5 rectangle, from top to bottom.
writeAt "+" 0 0
writeAt "|" 0 1
writeAt "|" 0 2
writeAt "|" 0 3
writeAt "+" 0 4

// Draw the bottom side, from left to right.
writeAt "-" 1 4 // shortcut: writeAt "---", 1, 4)
writeAt "-" 2 4 // ...
writeAt "-" 3 4 // ...
writeAt "+" 4 4

// Draw the right side, from bottom to top.
writeAt "|" 4 3
writeAt "|" 4 2
writeAt "|" 4 1
writeAt "+" 4 0

// Draw the top side, from right to left.
writeAt "-" 3 0 // shortcut: writeAt "---", 1, 0)
writeAt "-" 2 0 // ...
writeAt "-" 1 0 // ...

writeAt "All done!" 0 6
printfn ""


// This example produces the following results:
//
// +---+
// |   |
// |   |
// |   |
// +---+
//
// All done!

' This example demonstrates the 
'     Console.CursorLeft and 
'     Console.CursorTop properties, and the
'     Console.SetCursorPosition and 
'     Console.Clear methods.
Class Sample
   Protected Shared origRow As Integer
   Protected Shared origCol As Integer
   
   Protected Shared Sub WriteAt(s As String, x As Integer, y As Integer)
      Try
         Console.SetCursorPosition(origCol + x, origRow + y)
         Console.Write(s)
      Catch e As ArgumentOutOfRangeException
         Console.Clear()
         Console.WriteLine(e.Message)
      End Try
   End Sub
   
   Public Shared Sub Main()
      ' Clear the screen, then save the top and left coordinates.
      Console.Clear()
      origRow = Console.CursorTop
      origCol = Console.CursorLeft
      
      ' Draw the left side of a 5x5 rectangle, from top to bottom.
      WriteAt("+", 0, 0)
      WriteAt("|", 0, 1)
      WriteAt("|", 0, 2)
      WriteAt("|", 0, 3)
      WriteAt("+", 0, 4)
      
      ' Draw the bottom side, from left to right.
      WriteAt("-", 1, 4) ' shortcut: WriteAt("---", 1, 4)
      WriteAt("-", 2, 4) ' ...
      WriteAt("-", 3, 4) ' ...
      WriteAt("+", 4, 4)
      
      ' Draw the right side, from bottom to top.
      WriteAt("|", 4, 3)
      WriteAt("|", 4, 2)
      WriteAt("|", 4, 1)
      WriteAt("+", 4, 0)
      
      ' Draw the top side, from right to left.
      WriteAt("-", 3, 0) ' shortcut: WriteAt("---", 1, 0)
      WriteAt("-", 2, 0) ' ...
      WriteAt("-", 1, 0) ' ...
      '
      WriteAt("All done!", 0, 6)
      Console.WriteLine()
   End Sub
End Class
'
'This example produces the following results:
'
'+---+
'|   |
'|   |
'|   |
'+---+
'
'All done!
'

Hinweise

Die Verwendung Clear der -Methode entspricht dem Aufrufen des MS-DOS-Befehls cls im Eingabeaufforderungsfenster. Wenn die -Methode aufgerufen wird, scrollt der Cursor automatisch zur oberen linken Ecke des Fensters, und der Inhalt des Bildschirmpuffers wird mithilfe der aktuellen Hintergrundfarben im Vordergrund auf Leerzeichen Clear festgelegt.

Hinweis

Der Versuch, die -Methode auf aufruft, wenn die Ausgabe einer Konsolenanwendung an eine Datei umgeleitet wird, Clear löst eine IOException aus. Um dies zu verhindern, umschließen Sie immer einen Aufruf der Clear Methode in einer try...catch Block.

Gilt für