Bitmap ctor lève une exception

Question

Je n'arrive pas à trouver la solution. Ceci est mon code:

Dim wbRect As Rectangle = WebBrowser1.ClientRectangle 
    Dim wbBm As New Bitmap(WebBrowser1.ClientRectangle.Width, WebBrowser1.ClientRectangle.Height) 
    Dim gwb As Graphics = Graphics.FromImage(wbBm) 
    gwb.CopyFromScreen(WebBrowser1.PointToScreen(New Point(14, 31)), 
    New Point(0, 0), 
    New Size(PictureBox1.Width, PictureBox1.Height)) 
    wbBm.Save("c:\temp1.bmp") 
    PictureBox1.ImageLocation = "c:\temp1.bmp" 
    PictureBox1.BringToFront() 

    Dim bm As New Bitmap("c:\img1.bmp") //here appears an error - Parameter is not valid 

    Dim rect As New Rectangle(0, 0, bm.Width, bm.Height) 
    Dim bmpData As System.Drawing.Imaging.BitmapData = bm.LockBits(rect, _ 
    System.Drawing.Imaging.ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb) 

Que faire pour supprimer l'erreur?

Answer 1

Vous obtiendrez cette erreur si le fichier n'existe pas. Assurez-vous que img1.bmp existe avant d'essayer et ouvrez-le:

Dim fn As String = "c:\img1.bmp" 
    If File.Exists(fn) 
     Dim bm As New Bitmap(fn) ''here appears an error - Parameter is not valid 

     Dim rect As New Rectangle(0, 0, bm.Width, bm.Height) 
     Dim bmpData As System.Drawing.Imaging.BitmapData = bm.LockBits(rect, _ 
     System.Drawing.Imaging.ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb) 
    End If