Upload default image if no image is selected

Question

In my asp.net+VB+SQL web i have a page to upload image to sql table. I had attached teh code in text file as i was getting error while adding the code in this page.4

I am able to insert new image with this code. but i want to add a default image if user had not browsed and added image.

Answer 1

Hi @Baiju EP,

I had attached teh code in text file as i was getting error while adding the code in this page.

Your text file is not provided, you'd better provide error message and code.

I wrote an example according to your needs, you can refer to it.

First you need to add a default image and name it as Default.png and place it in your project.

Then you can make a judgment, when FileUpload has no files, upload the default picture.

        Dim bytes As Byte() = Nothing
        If Me.FileUpload1.HasFile Then
            ....
        Else
            filename = "Default.png"
            contenttype = "image/png"
            Dim defaultImage As System.Drawing.Image = System.Drawing.Image.FromFile(Server.MapPath("~/Default.png"))

            Using ms As MemoryStream = New MemoryStream()
                defaultImage.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg)
                bytes = ms.ToArray()
            End Using
        End If

All Code

<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
            <asp:FileUpload ID="FileUpload1" runat="server" />
<asp:Button ID="btnUpload" runat="server" Text="Upload" OnClick="Upload" />
<br />
<asp:Label ID="lblMessage" runat="server" Text="" Font-Names="Arial"></asp:Label>
<hr />
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="Id" HeaderText="Id" />
        <asp:BoundField DataField="Name" HeaderText="Name" />
        <asp:TemplateField HeaderText="Image">
            <ItemTemplate>
                <asp:Image ID="Image1" runat="server" ImageUrl='<%# ToBase64(Eval("Data")) %>' />
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

 Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Not Me.IsPostBack Then
            Me.GridView1.DataSource = GetData("SELECT Id, Name, Data FROM tblFiles")
            Me.GridView1.DataBind()
        End If
    End Sub
    Protected Function ToBase64(ByVal data As Object) As String
        Dim bytes As Byte() = CType(data, Byte())
        Dim base64String As String = Convert.ToBase64String(bytes, 0, bytes.Length)
        Return "data:image/png;base64," & base64String
    End Function

    Private Function GetData(ByVal query As String) As DataTable
        Dim dt As DataTable = New DataTable()
        Dim constr As String = ConfigurationManager.ConnectionStrings("DBCS").ConnectionString

        Using con As SqlConnection = New SqlConnection(constr)

            Using cmd As SqlCommand = New SqlCommand(query)

                Using sda As SqlDataAdapter = New SqlDataAdapter()
                    cmd.CommandType = CommandType.Text
                    cmd.Connection = con
                    sda.SelectCommand = cmd
                    sda.Fill(dt)
                End Using
            End Using

            Return dt
        End Using
    End Function

    Protected Sub Upload(ByVal sender As Object, ByVal e As EventArgs)
        Dim filePath As String = String.Empty
        Dim contenttype As String = String.Empty
        Dim filename As String = String.Empty
        Dim bytes As Byte() = Nothing

        If Me.FileUpload1.HasFile Then
            filePath = FileUpload1.PostedFile.FileName
            filename = Path.GetFileName(filePath)
            Dim ext As String = Path.GetExtension(filename)
            contenttype = String.Empty

            Select Case ext
                Case ".jpg"
                    contenttype = "image/jpg"
                Case ".png"
                    contenttype = "image/png"
                Case ".gif"
                    contenttype = "image/gif"
            End Select

            Using fs As Stream = FileUpload1.PostedFile.InputStream

                Using br As BinaryReader = New BinaryReader(fs)
                    bytes = br.ReadBytes(CType(fs.Length, Int32))
                End Using
            End Using
        Else
            filename = "Default.png"
            contenttype = "image/png"
            Dim defaultImage As System.Drawing.Image = System.Drawing.Image.FromFile(Server.MapPath("~/Default.png"))

            Using ms As MemoryStream = New MemoryStream()
                defaultImage.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg)
                bytes = ms.ToArray()
            End Using
        End If

        Dim query As String = "INSERT INTO tblFiles(Id,Name, ContentType, Data) VALUES (@Id,@Name, @ContentType, @Data)"
        Dim constr As String = ConfigurationManager.ConnectionStrings("DBCS").ConnectionString

        Using con As SqlConnection = New SqlConnection(constr)

            Using cmd As SqlCommand = New SqlCommand(query)
                cmd.Parameters.Add("@Id", SqlDbType.Int).Value = Convert.ToInt32(TextBox1.Text)
                cmd.Parameters.Add("@Name", SqlDbType.VarChar).Value = filename
                cmd.Parameters.Add("@ContentType", SqlDbType.VarChar).Value = contenttype
                cmd.Parameters.Add("@Data", SqlDbType.Binary).Value = bytes
                cmd.CommandType = CommandType.Text
                cmd.Connection = con
                con.Open()
                cmd.ExecuteNonQuery()
                con.Close()
            End Using
        End Using

        lblMessage.ForeColor = Color.Green
        lblMessage.Text = "File Uploaded Successfully"
        Response.Redirect(Request.Url.AbsoluteUri)
    End Sub

Best regards,
Lan Huang

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