asp.net中的上传图片问题以及create错误 [英] problem with upload image in asp.net and error with create

问题描述

大家好..

我正在与vb.net一起在asp.net中工作，以便在站点中创建组
但是我遇到了与此代码有关的问题，但是我认为我的代码是正确的.问题是，当我运行代码时，图片没有上传，并返回一个错误.请帮帮我.


在group.aspx中，我这样写:

Hi all..

I am working in asp.net with vb.net to create a group in the site
but I faced a problem with this code, but I feel that my code is correct. The problem is, when I run the code, the picture does not upload, and return there was an error. Please help me.


in group.aspx i wrote this:

<asp:FileUpload ID="imgUpload" runat="server" />
    <br />
      <asp:Label ID="lblResult" runat="server" ForeColor="#0066FF"></asp:Label>
<br />
   <asp:Image ID="Image1" style="width:200px" Runat="server" />

并以代码方式

and in code-behand

Imports Microsoft.VisualBasic
Imports System.Data
Imports System.Data.SqlClient
Imports System.Web.Configuration
Imports System.Data.OleDb
Imports System
Imports System.Configuration
Imports System.Web
Imports System.IO

Partial Class creatgroup
    Inherits System.Web.UI.Page

    Private Shared connectionString As String = _
  WebConfigurationManager.ConnectionStrings("Pubs").ConnectionString
    Private myConnection As New SqlConnection(connectionString)
   
    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Try

            Dim img As FileUpload = CType(imgUpload, FileUpload)
            Dim imgByte As Byte() = Nothing
            If img.HasFile AndAlso Not img.PostedFile Is Nothing Then
                ''To create a PostedFile
                Dim File As HttpPostedFile = imgUpload.PostedFile
                ''Create byte Array with file len
                imgByte = New Byte(File.ContentLength - 1) {}
                ''force the control to load data in array
                File.InputStream.Read(imgByte, 0, File.ContentLength)
            End If
            '' Insert the Group info and image into db


            myConnection.Open()
            Dim sql As String = "INSERT INTO Group(GroupName,Pic,Description,category,Privacy,News) VALUES(@enm, @eimg, @Description, @category, @Privacy, @News) @@IDENTITY"
            Dim cmd As SqlCommand = New SqlCommand(sql, myConnection)
            cmd.Parameters.AddWithValue("@enm", GroupName.Text)
            cmd.Parameters.AddWithValue("@eimg", imgByte)
            cmd.Parameters.AddWithValue("@Description", Description.Text)
            cmd.Parameters.AddWithValue("@category", Category.SelectedValue)

            If Privacy.Checked Then
                cmd.Parameters.AddWithValue("@Privacy", "True")
            Else
                cmd.Parameters.AddWithValue("@Privacy", "False")
            End If
            cmd.Parameters.AddWithValue("@News", News.Text)
            Dim id As String = cmd.ExecuteScalar.ToString
            lblResult.Text = String.Format("Group ID is {0}", id)
        Catch
            lblResult.Text = "There was an error"
        Finally
            myConnection.Close()
        End Try
    End Sub

End Class

问候:)

Regards :)

推荐答案

为什么在此行的末尾有大括号:

Why do you have curly braces at the end of this line :

imgByte = New Byte(File.ContentLength - 1) {}

meshosho写道:

meshosho wrote:

Dim img As FileUpload = CType(imgUpload，FileUpload)

Dim img As FileUpload = CType(imgUpload, FileUpload)

为什么需要强制转换?为什么它不是正确的类型?我认为这是页面上的控件吗?

您是否已遍历此代码以查看会发生什么?是imgByte Nothing打数据库代码吗?为什么即使没有图像也要运行数据库代码?

Why do you need to cast this ? Why is it not the right type already ? I assume this is the control on the page?

Have you stepped through this code to see what happens ? Is imgByte Nothing when it hits the DB code ? Why do you have the DB code run even if there is no image ?

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