vb.net怎樣在當(dāng)前已打開(kāi)的AutoCAD畫圖? 最好有個(gè)判斷語(yǔ)句, 如果CAD已打開(kāi), 在當(dāng)前畫圖; 如果沒(méi)有, 則打開(kāi)

Private Function isopen() As AutoCAD.AcadApplication

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Try

dim CADapp_temp AutoCAD.AcadApplication = GetObject(, "AutoCAD.Application")

return CADapp_temp

Catch ex As Exception

Return Nothing

End Try

End Function

'調(diào)用上面的函數(shù),如果為nothing表示沒(méi)有打開(kāi)，否則打開(kāi)并返回對(duì)象

vb.net 畫圖 如何保持圖形

不用PictureBoxTest.Image屬性，直接把圖形繪制到PictureBoxTest上面就可以了。

Dim?button?As?Integer?=?0

Private?Sub?Button1_Click(ByVal?sender?As?Object,?ByVal?e?As?EventArgs)?_

Handles?Button1.Click

Using?g?As?Graphics?=?Graphics.FromHwnd(PictureBoxTest.Handle)

Dim?penRed?As?Pen?=?New?Pen(Color.Red,?1)?????'定義紅色畫筆??

Dim?penblue?As?Pen?=?New?Pen(Color.Blue,?1)?'定義藍(lán)色畫筆?

If?button?=?0?Then

g.DrawLine(penRed,?0,?0,?100,?100)

button?=?1

ElseIf?button?=?1?Then

g.DrawLine(penblue,?100,?100,?200,?200)

button?=?0

End?If

End?Using

End?Sub

VB.net中如何畫圖？

VB.net與VB不同。

VB.net已經(jīng)有專門繪圖的類。

可以定義筆刷然后用Drawing類中的方法繪制。

Private Sub DrawEllipse()

Dim myPen As New System.Drawing.Pen(System.Drawing.Color.Red)

Dim formGraphics as System.Drawing.Graphics

formGraphics = Me.CreateGraphics()

formGraphics.DrawEllipse(myPen, New Rectangle(0,0,200,300))

myPen.Dispose()

formGraphics.Dispose()

End Sub

Private Sub DrawRectangle()

Dim myPen As New System.Drawing.Pen(System.Drawing.Color.Red)

Dim formGraphics as System.Drawing.Graphics

formGraphics = Me.CreateGraphics()

formGraphics.DrawRectangle(myPen, New Rectangle(0,0,200,300))

myPen.Dispose()

formGraphics.Dispose()

End Sub

關(guān)于vb.net中繪圖并保存圖片的問(wèn)題

Imports System.Drawing.Imaging

Public Class Form1

Dim imageName As String = "C:\Documents and Settings\...\1126.jpg "

Dim i As Image = Image.FromFile(imageName)

Dim g As Graphics = Graphics.FromImage(i) '此處從背景圖創(chuàng)建Greaphics

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

'劃線

Dim BluePen As New Pen(Color.Blue, 5)

BluePen.DashStyle = Drawing2D.DashStyle.Solid

g.DrawLine(BluePen, 100.0F, 170, 500.0F, 170)

g.Dispose()

PictureBox1.Image = i

End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

'退出

Me.Close()

End Sub

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click

'存盤

i.Save( "C:\testimage.jpg ", ImageFormat.Jpeg)

i.Dispose()

End Sub

Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

PictureBox1.Image = i

End Sub

End Class

vb.net 畫圖對(duì)象問(wèn)題

參考一下下面這段代碼：

‘?首先picturebox1?加載一張圖像

FolderBrowserDialog1.Description?=?"選擇圖片文件夾導(dǎo)入圖片"

FolderBrowserDialog1.ShowDialog()

path?=?FolderBrowserDialog1.SelectedPath()

If?path?=?""?Then?Return

strSrcFile?=?Dir(path??"\*.tif")

PictureBox1.Image?=?Image.FromFile(path??"\"??strSrcFile)

’??然后再在picturebox1中用graphic畫圖而不清空原圖像

'?建立一個(gè)畫圖對(duì)象

Dim?g?As?Graphics?=?Me.PictureBox1.CreateGraphics

‘?定義畫筆

Dim?myPen?As?System.Drawing.Pen?=?New?System.Drawing.Pen(Color.Blue)

’?畫出矩形框并且填充顏色（顏色保持50%的透明度，使得下面原來(lái)的圖片背景能看得到）

g.DrawRectangle(myPen,?New?System.Drawing.Rectangle(50,?50,?30,?20))

g.FillRectangle(New?SolidBrush(Color.FromArgb(50,?Color.YellowGreen)),?New?System.Drawing.Rectangle(50,?50,?30,?20))

'?最后釋放畫圖對(duì)象

g.Dispose()

效果大致如下圖所示：