Console.Clear 方法
定義
重要
部分資訊涉及發行前產品,在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊,不做任何明確或隱含的瑕疵擔保。
清除主控台緩衝區及包含顯示資訊的對應主控台視窗。
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 ()
- 屬性
例外狀況
發生 I/O 錯誤。
範例
下列範例 Clear 會使用方法來清除主控台,然後再執行迴圈、提示使用者選取前景和背景色彩,以及輸入要顯示的字串。 如果使用者選擇不結束程式,則會還原主控台的原始前景和背景色彩,然後 Clear 再次呼叫方法,然後再重新執行迴圈。
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
此範例會依賴 GetKeyPress
方法來驗證使用者選取的前景和背景色彩。
這個範例會示範 CursorLeft 和 CursorTop 屬性,以及和 SetCursorPosition Clear 方法。 此範例會定位游標,以決定下一次寫入的位置,以使用 "+"、"|" 和 "-" 字串的組合,以5個字元的矩形繪製5個字元。 請注意,您可以使用其他字串的組合,以較少的步驟來繪製矩形。
// 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!
'
備註
使用 Clear 方法相當於在 cls
命令提示字元視窗中叫用 MS-DOS 命令。 當 Clear 呼叫方法時,資料指標會自動滾動至視窗的左上角,而螢幕緩衝區的內容會使用目前的前景背景色彩設定為空白。
注意
Clear當主控台應用程式的輸出重新導向至檔案時,嘗試呼叫方法會擲回 IOException 。 為避免這種情況, 請一律將呼叫Clear包裝try
在 ...catch
塊。