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| Title | Load a picture so it doesn't lock the picture file in VB .NET |
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| Description | This example shows how to load a picture so it doesn't lock the picture file in VB .NET. |
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| Keywords | load picture, Bitmap, lock, lock file, sharing, file sharing |
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| Categories | Graphics, VB.NET, Files and Directories |
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When you create a Bitmap from a file, VB .NET locks the file for some reason (possibly so it can read the file again later if it needs to refresh the image).
To work around this problem, load the image into a Bitmap, create a new Bitmap and copy the image into it, and dispose of the original Bitmap. This example loads a Bitmap either the straightforward way or using this technique.
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Private m_Bitmap As Bitmap
Private Sub btnLoad_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles btnLoad.Click
' Get the file name.
Dim file_name As String = Application.StartupPath
file_name = file_name.Substring(0, _
file_name.LastIndexOf("\"))
file_name &= "\vbgp.jpg"
If radLocked.Checked Then
LoadLocked(file_name)
Else
LoadUnlocked(file_name)
End If
End Sub
' Load the image into a Bitmap
' and set the PictureBox's
' Image property to the Bitmap.
Private Sub LoadLocked(ByVal file_name As String)
If Not (m_Bitmap Is Nothing) Then m_Bitmap.Dispose()
m_Bitmap = New Bitmap(file_name)
PictureBox1.Image = m_Bitmap
End Sub
' Load the image into a Bitmap, clone it,
' and set the PictureBox's
' Image property to the Bitmap.
Private Sub LoadUnlocked(ByVal file_name As String)
If Not (m_Bitmap Is Nothing) Then m_Bitmap.Dispose()
Dim bm As New Bitmap(file_name)
m_Bitmap = New Bitmap(bm.Width, bm.Height)
Dim gr As Graphics = Graphics.FromImage(m_Bitmap)
gr.DrawImage(bm, 0, 0)
bm.Dispose()
PictureBox1.Image = m_Bitmap
End Sub
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