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asp.net - 如果 (fileUpload.HasFile)=false

转载 作者:行者123 更新时间:2023-12-04 20:51:44 29 4
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大家好,这里是代码,然后我将解释我的问题:-

 Protected Sub btnupload_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnUpload.Click
If (IsPostBack) Then
HandleUploadedFile()
Dim savePath As String = "Images\"
If (fileUpload.HasFile) Then
Dim fileName As String = fileUpload.FileName
savePath = Server.MapPath(savePath) + fileName
fileUpload.SaveAs(savePath)
Me.Label1.Text = "Your file was saved as " & fileName
adp.Insert(fileUpload.FileName)
Else
Me.Label1.Text = "You did not specify a file to upload."
End If
End If
End Sub

每次我跟踪代码时,它都会说 (fileUpload.HasFile)=false 之后再也看不到代码,然后跳转到 else 语句,这就是代码的其余部分

Private Sub HandleUploadedFile()
' get the root of the web site
Dim root As String = Server.MapPath("~/")

' clean up the path
If Not root.EndsWith("\") Then
root += "\"
End If

' make a folder to store the images in
Dim fileDirectory As String = root & "Images/"

' create the folder if it does not exist
If Not System.IO.Directory.Exists(fileDirectory) Then
System.IO.Directory.CreateDirectory(fileDirectory)
End If

' make a link to the new file
Dim link As String = "<a href='Images/{0}' target='_blank'>{1}</a>{2}{3}"

' loop through the file in the request
For i As Integer = 0 To Request.Files.Count - 1

' get the file instance
Dim fi As HttpPostedFile = Request.Files.[Get](i)

' create a byte array to store the file bytes
Dim fileBytes As Byte() = New Byte(fi.ContentLength - 1) {}

' fill the byte array
Using stream As System.IO.Stream = fi.InputStream
stream.Read(fileBytes, 0, fi.ContentLength)
End Using

' create a random file name
Dim fileName As String = Guid.NewGuid().ToString()

'write the original file to the file system
File.WriteAllBytes(fileDirectory + fileName & ".jpg", fileBytes)
litText.Text += String.Format(link, fileName & ".jpg", fileName & " Original", "<br/>", "")

' write the resized file to the file system
File.WriteAllBytes(fileDirectory + fileName & "_small.jpg", ResizeImageFile(fileBytes, 100))
litText.Text += String.Format(link, fileName & "_small.jpg", fileName & " Small", "<br/>", "<br/>")

' cleanup
litText.Visible = True
fileBytes = Nothing
Next
End Sub
Private Shared Function ResizeImageFile(ByVal imageFile As Byte(), ByVal targetSize As Integer) As Byte()
Using oldImage As System.Drawing.Image = System.Drawing.Image.FromStream(New MemoryStream(imageFile))
Dim newSize As Size = CalculateDimensions(oldImage.Size, targetSize)
Using newImage As New Bitmap(newSize.Width, newSize.Height, PixelFormat.Format24bppRgb)
Using canvas As Graphics = Graphics.FromImage(newImage)
canvas.SmoothingMode = SmoothingMode.AntiAlias
canvas.InterpolationMode = InterpolationMode.HighQualityBicubic
canvas.PixelOffsetMode = PixelOffsetMode.HighQuality
canvas.DrawImage(oldImage, New Rectangle(New Point(0, 0), newSize))
Dim m As New MemoryStream()
newImage.Save(m, ImageFormat.Jpeg)
Return m.GetBuffer()
End Using
End Using
End Using
End Function
Private Shared Function CalculateDimensions(ByVal oldSize As Size, ByVal targetSize As Integer) As Size
Dim newSize As New Size()
If oldSize.Height > oldSize.Width Then
newSize.Width = CInt((oldSize.Width * (CSng(targetSize) / CSng(oldSize.Height))))
newSize.Height = targetSize
Else
newSize.Width = targetSize
newSize.Height = CInt((oldSize.Height * (CSng(targetSize) / CSng(oldSize.Width))))
End If
Return newSize
End Function

End Class

最佳答案

检查您是否正在使用 UpdatePanel,如果是,则在 Page.Init 中执行以下操作:

protected void userView_Init(object sender, EventArgs e)
{
ScriptManager.GetCurrent(this).RegisterPostBackControl(uploadFileButton);
}

关于asp.net - 如果 (fileUpload.HasFile)=false,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/765683/

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