Question

我已经开始了一个新项目，我在一个图片框上搜索一些解决方案

使用此代码我能够在一个表单上绘制，但我需要在一个图片框上绘图，我已经尝试了多种方法，但我找不到在图片框中的屏幕截图上做到这一点的方法我需要改变什么才能让它发挥作用？这是我的代码

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

您是否有权直接写入c:\？你得到什么错误信息？也许尝试不保存图像文件

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

这绝对会在PictureBox上放置截图。我不知道还能告诉你什么

PictureBox1.Image = screenshot

在这里，我点击按钮6次，它一直在工作！

Answer 2

经过这么多次尝试后我才开始工作这是工作代码

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

如何在Picturebox VB.net上绘画

2 个答案: