如何在PictureBox中VB.net畫

Question

我開始一個新的項目，我尋找一些解決方案，在一個PictureBox

與此代碼，我能夠在窗體上繪製畫，但我需要借鑑一個圖片框，我嘗試了多種方式，但我無法找到在圖片框中的屏幕上做到這一點的方法 我需要改變才能使它工作？ 這是我的代碼

Public Class Form3 

Private Sub Form3_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
    Cursor = Cursors.Hand 
End Sub 

Dim mustPaint As Boolean = False 

Private Sub MouseEvent_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseDown 
    mustPaint = True 
End Sub 

Private Sub MouseEvent_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseMove 
    If mustPaint Then 
     Dim graphic As Graphics = CreateGraphics() 
     graphic.FillEllipse(New SolidBrush(Color.Red), e.X, e.Y, 10, 5) 
    End If 
End Sub 

Private Sub MouseEvent_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseUp 
    mustPaint = False 
End Sub 

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
    Dim bounds As Rectangle 
    Dim screenshot As System.Drawing.Bitmap 
    Dim graph As Graphics 
    bounds = Screen.PrimaryScreen.Bounds 
    screenshot = New System.Drawing.Bitmap(bounds.Width, bounds.Height, System.Drawing.Imaging.PixelFormat.Format32bppRgb) 
    graph = Graphics.FromImage(screenshot) 
    graph.CopyFromScreen(0, 0, 0, 0, bounds.Size, CopyPixelOperation.SourceCopy) 
    screenshot.Save("c:\\dcap.jpg", Imaging.ImageFormat.Bmp) 
    PictureBox1.BackgroundImage = screenshot 
End Sub 
End Class 

Answer 1

你有權利直接寫入到c:\？你會得到什麼錯誤信息？ 也許嘗試不保存圖像文件

'screenshot.Save("c:\\dcap.jpg", Imaging.ImageFormat.Bmp) 

這絕對是把一個屏幕截圖上的圖片框。我不知道還有什麼可以告訴你的

PictureBox1.Image = screenshot 

在這裏，我點擊按鈕6次，它保持工作！後

Answer 2

好嘗試了很多次，我得到它的工作 這是工作的代碼

Imports System.Drawing.Drawing2D 
Public Class Form3 

Private Sub Form3_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) 
End Sub 

Dim mustPaint As Boolean = False 
Private lastPT As Point 
Private signature As New GraphicsPath 

Private Sub PictureBox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown 
    If Not IsNothing(signature) Then 
     If e.Button = Windows.Forms.MouseButtons.Left Then 
      lastPT = New Point(e.X, e.Y) 
     End If 
    End If 
End Sub 

Private Sub PictureBox1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseMove 
    If Not IsNothing(signature) Then 
     If e.Button = Windows.Forms.MouseButtons.Left Then 
      Dim curPt As New Point(e.X, e.Y) 
      signature.AddLine(lastPT, curPt) 
      lastPT = curPt 
      PictureBox1.Refresh() 
     End If 
    End If 
End Sub 

Private Sub PictureBox1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseUp 
    If Not IsNothing(signature) Then 
     If e.Button = Windows.Forms.MouseButtons.Left Then 
      signature.StartFigure() 
     End If 
    End If 
End Sub 

Private Sub PictureBox1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles PictureBox1.Paint 
    If Not IsNothing(signature) Then 
     e.Graphics.DrawPath(Pens.Black, signature) 
    End If 
End Sub 

Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click 
    signature.Reset() 
    PictureBox1.Refresh() 
End Sub 

Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click 
    Dim bmp As New Drawing.Bitmap(PictureBox1.Width, PictureBox1.Height) 
    PictureBox1.DrawToBitmap(bmp, PictureBox1.ClientRectangle) 
    bmp.Save(System.IO.Path.Combine(My.Computer.FileSystem.SpecialDirectories.MyDocuments, "test.bmp"), System.Drawing.Imaging.ImageFormat.Bmp) 
End Sub 
Private Sub MouseEvent_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseDown 
    mustPaint = True 
End Sub 

Private Sub MouseEvent_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseMove 
    If mustPaint Then 
     Dim graphic As Graphics = CreateGraphics() 
     graphic.FillEllipse(New SolidBrush(Color.Red), e.X, e.Y, 10, 5) 
    End If 
End Sub 

Private Sub MouseEvent_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyBase.MouseUp 
    mustPaint = False 
End Sub 


Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
    Dim bounds As Rectangle 
    Dim screenshot As System.Drawing.Bitmap 
    Dim graph As Graphics 
    bounds = Screen.PrimaryScreen.Bounds 
    screenshot = New System.Drawing.Bitmap(bounds.Width, bounds.Height, System.Drawing.Imaging.PixelFormat.Format32bppRgb) 
    graph = Graphics.FromImage(screenshot) 
    graph.CopyFromScreen(0, 0, 0, 0, bounds.Size, CopyPixelOperation.SourceCopy) 
    screenshot.Save("c:\\dcap.jpg", Imaging.ImageFormat.Bmp) 
    'PictureBox1.BackgroundImage = screenshot 
    PictureBox1.Image = screenshot 


End Sub 

End Class