Question

在vb.net中，运行代码之后在picturebox里用鼠标移动事件，画了一条曲线，我想保存这个曲线成图片格式

这是我写的代码，保存之后只是一张空白图片……而没有我画的曲线啊？？帮我看看
Public Class Form1
Dim preX As Single
Dim preY As Single
Private pStart, pEnd As Point
Dim ep As New Pen(Color.Red, 1)
Public image As Bitmap = Nothing
'Dim bm As New Bitmap(500, 500)
'Dim bm = New Bitmap(Me.PictureBox1.Width, Me.PictureBox1.Height, Me.PictureBox1.CreateGraphics)
'Dim g = Graphics.FromImage(bm)
Dim g As Graphics
Private Sub Picturebox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
Me.PictureBox1.Controls.Clear()
image = New Bitmap(Me.PictureBox1.Width, Me.PictureBox1.Height)
Graphics.FromImage(image).Clear(Color.White)
Me.PictureBox1.Image = DirectCast(image.Clone(), Bitmap)
If e.Button = Windows.Forms.MouseButtons.Left Then
pStart.X = e.X
pStart.Y = e.Y
End If

End Sub
Private Sub PictureBox1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseMove
image = New Bitmap(Me.PictureBox1.Width, Me.PictureBox1.Height)
Using gr As Graphics = Graphics.FromImage(image)
Dim g As Graphics = PictureBox1.CreateGraphics()
If e.Button = Windows.Forms.MouseButtons.Left Then
pEnd.X = e.X
pEnd.Y = e.Y
g.DrawLine(ep, pStart, pEnd)
ListBox1.Items.Add(pStart.X & " " & pStart.Y)
pStart = pEnd
End If
End Using
' PictureBox1.Image. = bm

End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
PictureBox1.Image.Save("C:\Users\Administrator\Desktop\123.jpeg")
End Sub

Answer 1

Picture1.AutoRedraw = True
'必须设为 True ，这样才能图形和文本输出到屏幕，并存储在内存的图象中。然后可以使用 Image 属性
SavePicture Picture1.Image, "C:\Pic1.BMP"
'此代码保存的是 Picture1 里使用 Line 、 Circle 、PaintPicture 等绘图方法画出来的图片，包括背景色以及 PICTURE 属性指定的背景图片
'Picture1.Image 就是调用了 Picture1 的 Image 属性
'"C:\Pic1.BMP" 就是保存的文件名
'注意：Image 属性输出的图片总是 BMP 格式的。如果要保存成 JPG/GIF 等格式，则必须转换！
SavePicture Picture1.Picture, "C:\Pic1.BMP"
'此代码保存的是 Picture1 里的 PICTURE 属性里的图片
'PICTURE 属性输出的图片格式取决于 PICTURE 属性里的图片的格式。
'例如，如果使用 LoadPicture("C:\B1.GIF") 导入了一个 GIF 图片，则 PICTURE 属性输出的图片的格式就是 GIF 格式的

Answer 2

学习一下