Control.Invalidate 方法

定義

使控制項的特定區域失效,並且造成傳送繪製訊息至控制項。Invalidates a specific region of the control and causes a paint message to be sent to the control.

多載

Invalidate(Region, Boolean)

使控制項的指定區域失效 (將它加入控制項的更新區域,而這個區域會在下一個繪製作業中重新繪製),並使繪製訊息傳送至控制項。Invalidates the specified region of the control (adds it to the control's update region, which is the area that will be repainted at the next paint operation), and causes a paint message to be sent to the control. 選擇性使指派至控制項的子控制項失效。Optionally, invalidates the child controls assigned to the control.

Invalidate(Rectangle, Boolean)

使控制項的指定區域失效 (將它加入控制項的更新區域,而這個區域會在下一個繪製作業中重新繪製),並使繪製訊息傳送至控制項。Invalidates the specified region of the control (adds it to the control's update region, which is the area that will be repainted at the next paint operation), and causes a paint message to be sent to the control. 選擇性使指派至控制項的子控制項失效。Optionally, invalidates the child controls assigned to the control.

Invalidate(Region)

使控制項的指定區域失效 (將它加入控制項的更新區域,而這個區域會在下一個繪製作業中重新繪製),並使繪製訊息傳送至控制項。Invalidates the specified region of the control (adds it to the control's update region, which is the area that will be repainted at the next paint operation), and causes a paint message to be sent to the control.

Invalidate(Rectangle)

使控制項的指定區域失效 (將它加入控制項的更新區域,而這個區域會在下一個繪製作業中重新繪製),並使繪製訊息傳送至控制項。Invalidates the specified region of the control (adds it to the control's update region, which is the area that will be repainted at the next paint operation), and causes a paint message to be sent to the control.

Invalidate(Boolean)

使控制項的特定區域失效,並且造成傳送繪製訊息至控制項。Invalidates a specific region of the control and causes a paint message to be sent to the control. 選擇性使指派至控制項的子控制項失效。Optionally, invalidates the child controls assigned to the control.

Invalidate()

讓控制項的整個介面失效,並重新繪製控制項。Invalidates the entire surface of the control and causes the control to be redrawn.

Invalidate(Region, Boolean)

使控制項的指定區域失效 (將它加入控制項的更新區域,而這個區域會在下一個繪製作業中重新繪製),並使繪製訊息傳送至控制項。Invalidates the specified region of the control (adds it to the control's update region, which is the area that will be repainted at the next paint operation), and causes a paint message to be sent to the control. 選擇性使指派至控制項的子控制項失效。Optionally, invalidates the child controls assigned to the control.

public:
 void Invalidate(System::Drawing::Region ^ region, bool invalidateChildren);
public void Invalidate (System.Drawing.Region region, bool invalidateChildren);
member this.Invalidate : System.Drawing.Region * bool -> unit

參數

region
Region

要使其失效的 RegionThe Region to invalidate.

invalidateChildren
Boolean

true 會使控制項的子控制項失效,否則為 falsetrue to invalidate the control's child controls; otherwise, false.

備註

呼叫 Invalidate 方法並不會強制同步繪製;若要強制同步繪製,請在呼叫 Invalidate 方法之後,呼叫 Update 方法。Calling the Invalidate method does not force a synchronous paint; to force a synchronous paint, call the Update method after calling the Invalidate method. 呼叫這個方法時,如果沒有參數,則會將整個工作區新增至更新區域。When this method is called with no parameters, the entire client area is added to the update region.

另請參閱

Invalidate(Rectangle, Boolean)

使控制項的指定區域失效 (將它加入控制項的更新區域,而這個區域會在下一個繪製作業中重新繪製),並使繪製訊息傳送至控制項。Invalidates the specified region of the control (adds it to the control's update region, which is the area that will be repainted at the next paint operation), and causes a paint message to be sent to the control. 選擇性使指派至控制項的子控制項失效。Optionally, invalidates the child controls assigned to the control.

public:
 void Invalidate(System::Drawing::Rectangle rc, bool invalidateChildren);
public void Invalidate (System.Drawing.Rectangle rc, bool invalidateChildren);
member this.Invalidate : System.Drawing.Rectangle * bool -> unit
Public Sub Invalidate (rc As Rectangle, invalidateChildren As Boolean)

參數

rc
Rectangle

Rectangle,表示要使其失效的區域。A Rectangle that represents the region to invalidate.

invalidateChildren
Boolean

true 會使控制項的子控制項失效,否則為 falsetrue to invalidate the control's child controls; otherwise, false.

備註

呼叫 Invalidate 方法並不會強制同步繪製;若要強制同步繪製,請在呼叫 Invalidate 方法之後,呼叫 Update 方法。Calling the Invalidate method does not force a synchronous paint; to force a synchronous paint, call the Update method after calling the Invalidate method. 呼叫這個方法時,如果沒有參數,則會將整個工作區新增至更新區域。When this method is called with no parameters, the entire client area is added to the update region.

另請參閱

Invalidate(Region)

使控制項的指定區域失效 (將它加入控制項的更新區域,而這個區域會在下一個繪製作業中重新繪製),並使繪製訊息傳送至控制項。Invalidates the specified region of the control (adds it to the control's update region, which is the area that will be repainted at the next paint operation), and causes a paint message to be sent to the control.

public:
 void Invalidate(System::Drawing::Region ^ region);
public void Invalidate (System.Drawing.Region region);
member this.Invalidate : System.Drawing.Region -> unit

參數

region
Region

要使其失效的 RegionThe Region to invalidate.

備註

呼叫 Invalidate 方法並不會強制同步繪製;若要強制同步繪製,請在呼叫 Invalidate 方法之後,呼叫 Update 方法。Calling the Invalidate method does not force a synchronous paint; to force a synchronous paint, call the Update method after calling the Invalidate method. 呼叫這個方法時,如果沒有參數,則會將整個工作區新增至更新區域。When this method is called with no parameters, the entire client area is added to the update region.

另請參閱

Invalidate(Rectangle)

使控制項的指定區域失效 (將它加入控制項的更新區域,而這個區域會在下一個繪製作業中重新繪製),並使繪製訊息傳送至控制項。Invalidates the specified region of the control (adds it to the control's update region, which is the area that will be repainted at the next paint operation), and causes a paint message to be sent to the control.

public:
 void Invalidate(System::Drawing::Rectangle rc);
public void Invalidate (System.Drawing.Rectangle rc);
member this.Invalidate : System.Drawing.Rectangle -> unit
Public Sub Invalidate (rc As Rectangle)

參數

rc
Rectangle

Rectangle,表示要使其失效的區域。A Rectangle that represents the region to invalidate.

備註

呼叫 Invalidate 方法並不會強制同步繪製;若要強制同步繪製,請在呼叫 Invalidate 方法之後,呼叫 Update 方法。Calling the Invalidate method does not force a synchronous paint; to force a synchronous paint, call the Update method after calling the Invalidate method. 呼叫這個方法時,如果沒有參數,則會將整個工作區新增至更新區域。When this method is called with no parameters, the entire client area is added to the update region.

另請參閱

Invalidate(Boolean)

使控制項的特定區域失效,並且造成傳送繪製訊息至控制項。Invalidates a specific region of the control and causes a paint message to be sent to the control. 選擇性使指派至控制項的子控制項失效。Optionally, invalidates the child controls assigned to the control.

public:
 void Invalidate(bool invalidateChildren);
public void Invalidate (bool invalidateChildren);
member this.Invalidate : bool -> unit
Public Sub Invalidate (invalidateChildren As Boolean)

參數

invalidateChildren
Boolean

true 會使控制項的子控制項失效,否則為 falsetrue to invalidate the control's child controls; otherwise, false.

備註

呼叫 Invalidate 方法並不會強制同步繪製;若要強制同步繪製,請在呼叫 Invalidate 方法之後,呼叫 Update 方法。Calling the Invalidate method does not force a synchronous paint; to force a synchronous paint, call the Update method after calling the Invalidate method. 呼叫這個方法時,如果沒有參數,則會將整個工作區新增至更新區域。When this method is called with no parameters, the entire client area is added to the update region.

另請參閱

Invalidate()

讓控制項的整個介面失效,並重新繪製控制項。Invalidates the entire surface of the control and causes the control to be redrawn.

public:
 void Invalidate();
public void Invalidate ();
member this.Invalidate : unit -> unit
Public Sub Invalidate ()

範例

下列程式碼範例可讓使用者將影像或影像檔案拖曳至表單上,並讓它在卸載時顯示。The following code example enables the user to drag an image or image file onto the form, and have it be displayed at the point on it is dropped. 每次繪製表單時,都會覆寫 OnPaint 方法來重新繪製影像;否則,只有在下一次重新繪製之後,才會保存影像。The OnPaint method is overridden to repaint the image each time the form is painted; otherwise the image would only persist until the next repainting. DragEnter 事件處理方法會決定要拖曳至表單中的資料類型,並提供適當的意見反應。The DragEnter event-handling method determines the type of data being dragged into the form and provides the appropriate feedback. 如果可以從資料建立 ImageDragDrop 事件處理方法會在表單上顯示影像。The DragDrop event-handling method displays the image on the form, if an Image can be created from the data. 因為 DragEventArgs.XDragEventArgs.Y 值是螢幕座標,所以範例會使用 PointToClient 方法,將它們轉換成用戶端座標。Because the DragEventArgs.X and DragEventArgs.Y values are screen coordinates, the example uses the PointToClient method to convert them to client coordinates.

private:
   Image^ picture;
   Point pictureLocation;

public:
   Form1()
   {
      
      // Enable drag-and-drop operations and
      // add handlers for DragEnter and DragDrop.
      this->AllowDrop = true;
      this->DragDrop += gcnew DragEventHandler( this, &Form1::Form1_DragDrop );
      this->DragEnter += gcnew DragEventHandler( this, &Form1::Form1_DragEnter );
   }

protected:
   virtual void OnPaint( PaintEventArgs^ e ) override
   {
      
      // If there is an image and it has a location,
      // paint it when the Form is repainted.
      Form::OnPaint( e );
      if ( this->picture != nullptr && this->pictureLocation != Point::Empty )
      {
         e->Graphics->DrawImage( this->picture, this->pictureLocation );
      }
   }

private:
   void Form1_DragDrop( Object^ /*sender*/, DragEventArgs^ e )
   {
      
      // Handle FileDrop data.
      if ( e->Data->GetDataPresent( DataFormats::FileDrop ) )
      {
         // Assign the file names to a String* array, in
         // case the user has selected multiple files.
         array<String^>^files = (array<String^>^)e->Data->GetData( DataFormats::FileDrop );
         try
         {
            // Assign the first image to the picture variable.
            this->picture = Image::FromFile( files[ 0 ] );
            
            // Set the picture location equal to the drop point.
            this->pictureLocation = this->PointToClient( Point(e->X,e->Y) );
         }
         catch ( Exception^ ex ) 
         {
            MessageBox::Show( ex->Message );
            return;
         }

      }
      
      // Handle Bitmap data.
      if ( e->Data->GetDataPresent( DataFormats::Bitmap ) )
      {
         try
         {
            // Create an Image and assign it to the picture variable.
            this->picture = dynamic_cast<Image^>(e->Data->GetData( DataFormats::Bitmap ));

            // Set the picture location equal to the drop point.
            this->pictureLocation = this->PointToClient( Point(e->X,e->Y) );
         }
         catch ( Exception^ ex ) 
         {
            MessageBox::Show( ex->Message );
            return;
         }
      }
      
      // Force the form to be redrawn with the image.
      this->Invalidate();
   }

   void Form1_DragEnter( Object^ /*sender*/, DragEventArgs^ e )
   {
      // If the data is a file or a bitmap, display the copy cursor.
      if ( e->Data->GetDataPresent( DataFormats::Bitmap ) || e->Data->GetDataPresent( DataFormats::FileDrop ) )
      {
         e->Effect = DragDropEffects::Copy;
      }
      else
      {
         e->Effect = DragDropEffects::None;
      }
   }
private Image picture;
private Point pictureLocation;

public Form1()
{
   // Enable drag-and-drop operations and 
   // add handlers for DragEnter and DragDrop.
   this.AllowDrop = true;
   this.DragDrop += new DragEventHandler(this.Form1_DragDrop);
   this.DragEnter += new DragEventHandler(this.Form1_DragEnter);
}

protected override void OnPaint(PaintEventArgs e)
{
   // If there is an image and it has a location, 
   // paint it when the Form is repainted.
   base.OnPaint(e);
   if(this.picture != null && this.pictureLocation != Point.Empty)
   {
      e.Graphics.DrawImage(this.picture, this.pictureLocation);
   }
}

private void Form1_DragDrop(object sender, DragEventArgs e)
{
   // Handle FileDrop data.
   if(e.Data.GetDataPresent(DataFormats.FileDrop) )
   {
      // Assign the file names to a string array, in 
      // case the user has selected multiple files.
      string[] files = (string[])e.Data.GetData(DataFormats.FileDrop);
      try
      {
         // Assign the first image to the picture variable.
         this.picture = Image.FromFile(files[0]);
         // Set the picture location equal to the drop point.
         this.pictureLocation = this.PointToClient(new Point(e.X, e.Y) );
      }
      catch(Exception ex)
      {
         MessageBox.Show(ex.Message);
         return;
      }
   }

   // Handle Bitmap data.
   if(e.Data.GetDataPresent(DataFormats.Bitmap) )
   {
      try
      {
         // Create an Image and assign it to the picture variable.
         this.picture = (Image)e.Data.GetData(DataFormats.Bitmap);
         // Set the picture location equal to the drop point.
         this.pictureLocation = this.PointToClient(new Point(e.X, e.Y) );
      }
      catch(Exception ex)
      {
         MessageBox.Show(ex.Message);
         return;
      }
   }
   // Force the form to be redrawn with the image.
   this.Invalidate();
}

private void Form1_DragEnter(object sender, DragEventArgs e)
{
   // If the data is a file or a bitmap, display the copy cursor.
   if (e.Data.GetDataPresent(DataFormats.Bitmap) || 
      e.Data.GetDataPresent(DataFormats.FileDrop) ) 
   {
      e.Effect = DragDropEffects.Copy;
   }
   else
   {
      e.Effect = DragDropEffects.None;
   }
}
Private picture As Image
Private pictureLocation As Point

Public Sub New()
   ' Enable drag-and-drop operations.
   Me.AllowDrop = True
End Sub

Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
   MyBase.OnPaint(e)

   ' If there is an image and it has a location, 
   ' paint it when the Form is repainted.
   If (Me.picture IsNot Nothing) And _
     Not (Me.pictureLocation.Equals(Point.Empty)) Then
      e.Graphics.DrawImage(Me.picture, Me.pictureLocation)
   End If
End Sub

Private Sub Form1_DragDrop(ByVal sender As Object, _
  ByVal e As DragEventArgs) Handles MyBase.DragDrop
   ' Handle FileDrop data.
   If e.Data.GetDataPresent(DataFormats.FileDrop) Then
      ' Assign the file names to a string array, in 
      ' case the user has selected multiple files.
      Dim files As String() = CType(e.Data.GetData(DataFormats.FileDrop), String())
      Try
         ' Assign the first image to the 'picture' variable.
         Me.picture = Image.FromFile(files(0))
         ' Set the picture location equal to the drop point.
         Me.pictureLocation = Me.PointToClient(New Point(e.X, e.Y))
      Catch ex As Exception
         MessageBox.Show(ex.Message)
         Return
      End Try
   End If

   ' Handle Bitmap data.
   If e.Data.GetDataPresent(DataFormats.Bitmap) Then
      Try
         ' Create an Image and assign it to the picture variable.
         Me.picture = CType(e.Data.GetData(DataFormats.Bitmap), Image)
         ' Set the picture location equal to the drop point.
         Me.pictureLocation = Me.PointToClient(New Point(e.X, e.Y))
      Catch ex As Exception
         MessageBox.Show(ex.Message)
         Return
      End Try
   End If

   ' Force the form to be redrawn with the image.
   Me.Invalidate()
End Sub

Private Sub Form1_DragEnter(ByVal sender As Object, _
  ByVal e As DragEventArgs) Handles MyBase.DragEnter
   ' If the data is a file or a bitmap, display the copy cursor.
   If e.Data.GetDataPresent(DataFormats.Bitmap) _
      Or e.Data.GetDataPresent(DataFormats.FileDrop) Then
      e.Effect = DragDropEffects.Copy
   Else
      e.Effect = DragDropEffects.None
   End If
End Sub

備註

呼叫 Invalidate 方法並不會強制同步繪製;若要強制同步繪製,請在呼叫 Invalidate 方法之後,呼叫 Update 方法。Calling the Invalidate method does not force a synchronous paint; to force a synchronous paint, call the Update method after calling the Invalidate method. 呼叫這個方法時,如果沒有參數,則會將整個工作區新增至更新區域。When this method is called with no parameters, the entire client area is added to the update region.

另請參閱

適用於