Console.Clear Console.Clear Console.Clear Console.Clear Method

Определение

Удаляет из буфера консоли и ее окна отображаемую информацию.Clears the console buffer and corresponding console window of display information.

public:
 static void Clear();
public static void Clear ();
static member Clear : unit -> unit
Public Shared Sub Clear ()

Исключения

Ошибка ввода/вывода.An I/O error occurred.

Примеры

В следующем примере Clear метод очищает консоль перед выполнением цикла, предложит пользователю выбрать цвет переднего плана и фона и ввести строку для вывода.The following example uses the Clear method to clear the console before it executes a loop, prompts the user to select a foreground and background color and to enter a string to display. Если пользователь решил не выходить из программы, восстанавливаются исходные цвета и цвет фона консоли, а Clear метод вызывается снова перед повторным выполнением цикла.If the user chooses not to exit the program, the console's original foreground and background colors are restored and the Clear method is called again before re-executing the loop.

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; 
   }
}
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

В этом примере используется GetKeyPress метод для проверки выбора пользователем переднего плана и цвета фона.The example relies on a GetKeyPress method to validate the user's selection of a foreground and background color.

В CursorLeft этом примере демонстрируются CursorTop свойства и, а SetCursorPosition также Clear методы и.This example demonstrates the CursorLeft and CursorTop properties, and the SetCursorPosition and Clear methods. В примере размещается курсор, который определяет, где будет выполняться следующая запись, чтобы нарисовать 5-символьный прямоугольник на 5 символов, используя сочетание строк "+|", "" и "-".The example positions the cursor, which determines where the next write will occur, to draw a 5 character by 5 character rectangle using a combination of "+", "|", and "-" strings. Обратите внимание, что прямоугольник может быть нарисован с меньшим количеством шагов, используя сочетание других строк.Note that the rectangle could be drawn with fewer steps using a combination of other strings.

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

Комментарии

Использование метода эквивалентно вызову команды MS-DOS cls в окне командной строки. ClearUsing the Clear method is equivalent invoking the MS-DOS cls command in the command prompt window. При вызове Clear метода курсор автоматически прокручивается к левому верхнему углу окна, а содержимое буфера экрана устанавливается в пустое значение с использованием текущих фоновых цветов переднего плана.When the Clear method is called, the cursor automatically scrolls to the top-left corner of the window and the contents of the screen buffer are set to blanks using the current foreground background colors.

Примечание

Попытка вызвать Clear метод, когда выходные данные консольного приложения перенаправляется в файл, IOExceptionвызывает исключение.Attempting to call the Clear method when a console application's output is redirected to a file throws a IOException. Чтобы избежать этого, всегда заключайте вызов Clear метода tryв...catchTo prevent this, always wrap a call to the Clear method in a trycatch блок.block.

Применяется к