Problems with button control containing text and image

Discussion in 'ASP .Net' started by David, Sep 7, 2006.

  1. David

    David Guest

    Hello all. I am trying to implement my first server control and have
    run into two problems that I cannot solve. I need the assistance of
    someone with more experience.

    My goal was to create an input button that would allow for both text
    and an image on it. I am attempting to accomplish this by basing off
    of the asp:button control. I added a property for the image url and
    one to determine if the image is displayed on the left or right of the
    text. I am also overriding the necessary methods so that the html that
    is rendered is correct. (The code is included below.)

    In my aspx file I put two instances of the control:

    <tlic:ImageTextButton ID="btnSaveAll" runat="server" Text="Save All"
    ImageUrl="Images/Diskette.gif" />
    <tlic:ImageTextButton ID="btnEmailAll" runat="server" Text="Email All"
    ImageUrl="Images/Envelope.gif" OnClientClick="return GetRecipients();"
    />

    It renders the following in the html to the browser:

    <button type="submit" name="btnSaveAll" value="Save All"
    id="btnSaveAll"><img id="btnSaveAll_Img" name="btnSaveAll:Img"
    src="Images/Diskette.gif" border="0" />&nbsp;Save All</button>
    <button type="submit" name="btnEmailAll" value="Email All"
    onclick="return GetRecipients();" language="javascript"
    id="btnEmailAll"><img id="btnEmailAll_Img" name="btnEmailAll:Img"
    src="Images/Envelope.gif" border="0" />&nbsp;Email All</button>

    So far, all is good. The problems come in when I click one of the
    buttons. The first problem is that ASP.NET complains when validating
    the response because the value of the button is being returned as the
    inner html rather than what is in the Value attribute. Since there is
    an IMG tag there it thinks the data is suspect. Here is the form data:

    __EVENTTARGET
    __EVENTARGUMENT
    __VIEWSTATE /wEPDwUKMTgzNj(snip)...
    emailRecipients
    gridAuthKeys:_ctl2:tbRANumber
    gridAuthKeys:_ctl2:tbPONumber
    gridAuthKeys:_ctl2:tbMustArriveBy
    btnSaveAll <IMG id=btnSaveAll_Img src="Images/Diskette.gif" border=0
    name=btnSaveAll:Img>&nbsp;Save All
    btnEmailAll <IMG id=btnEmailAll_Img src="Images/Envelope.gif" border=0
    name=btnEmailAll:Img>&nbsp;Email All

    I figured I would deal with that later so I turned off page validation
    to see if the rest of the processing would work. The second problem is
    that no matter which button I click, ASP.NET fires off the event
    handler for which ever is the last, or second, button, in this case
    "email all". Again, I think the value of the button controls is
    messing it up.

    I tried setting the buttons to UseSubmit=False vs. True but that
    didn't help. An interesting thing to note is that according to the
    HTML spec, if a form contains more than one submit button, only the one
    clicked is supposed to be included in the form data returned. This is
    not what is happening here.

    I would greatly appreciate any time that someone could spend to help me
    with this.

    Regards,

    David

    Here is the code for the control:

    Imports Microsoft.VisualBasic
    Imports System
    Imports System.Web
    Imports System.Web.UI
    Imports System.ComponentModel
    Imports System.Drawing.Design

    Namespace TLI.Controls

    ''' <summary>
    ''' A control rendered as a button that has both an image and text.
    ''' </summary>
    ''' <remarks></remarks>
    <ToolboxData("<{0}:ImageTextButton
    runat=server></{0}:ImageTextButton>")> _
    Public Class ImageTextButton
    Inherits WebControls.Button

    <Bindable(True), _
    Category("Appearance"), _
    DefaultValue(""), _
    Editor("System.Windows.Forms.ImageEditorIndex, System.Design",
    GetType(UITypeEditor)), _
    Description("The image to appear on the button")> _
    Public Property ImageUrl() As String
    Get
    Dim s As String = CStr(ViewState("ImageURL"))
    Return IIf(s Is Nothing, "", s)
    End Get
    Set(ByVal value As String)
    ViewState("ImageURL") = value
    End Set
    End Property

    <Bindable(True), _
    Category("Appearance"), _
    DefaultValue(True), _
    Description("True if the image is to appear to the left of the
    text")> _
    Public Property ImageLeft() As Boolean
    Get
    Dim o As Object = ViewState("ImageLeft")
    Return IIf(o Is Nothing, True, CBool(o))
    End Get
    Set(ByVal value As Boolean)
    ViewState("ImageLeft") = value
    End Set
    End Property

    Protected Overrides ReadOnly Property TagKey() As
    HtmlTextWriterTag
    Get
    Return HtmlTextWriterTag.Button
    End Get
    End Property

    Protected Overrides Sub RenderContents(ByVal writer As
    System.Web.UI.HtmlTextWriter)
    If ImageLeft Then
    RenderImage(writer)
    writer.Write("&nbsp;")
    End If
    writer.Write(Text)
    If Not ImageLeft Then
    writer.Write("&nbsp;")
    RenderImage(writer)
    End If
    End Sub

    Private Sub RenderImage(ByVal writer As
    System.Web.UI.HtmlTextWriter)
    writer.AddAttribute(HtmlTextWriterAttribute.Id, ID &
    "_Img")
    writer.AddAttribute(HtmlTextWriterAttribute.Name, ID &
    ":Img")
    writer.AddAttribute(HtmlTextWriterAttribute.Src, ImageUrl)
    writer.AddAttribute(HtmlTextWriterAttribute.Border, "0")
    writer.RenderBeginTag(HtmlTextWriterTag.Img)
    writer.RenderEndTag()
    End Sub
    End Class
    End Namespace
    David, Sep 7, 2006
    #1
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  2. David

    wwwtar

    Joined:
    Oct 2, 2006
    Messages:
    3
    working?

    Any chance you got your button control working? I'm looking to code the same type of control... i need support for buttons that contain image and text.
    wwwtar, Nov 30, 2006
    #2
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