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Unexpected disabled button behavior

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AsyncUpload

This is a migrated thread and some comments may be shown as answers.

Olaf asked on 20 Aug 2016, 12:46 PM

Hi i used your example http://demos.telerik.com/aspnet-ajax/asyncupload/examples/persistuploadedfiles/defaultvb.aspx?show-source=true

I modified it a bit to be more simple:

TestUpload.aspx

001.<%@ Page Language="vb" CodeFile="TestUpload.aspx.vb" AutoEventWireup="true" Inherits="TestUpload" %>

002.

003.<%@ Register TagPrefix="telerik" Namespace="Telerik.Web.UI" Assembly="Telerik.Web.UI" %>

004.

005.<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

006.<html xmlns='http://www.w3.org/1999/xhtml'>

007.<head runat="server">

008. <title>Telerik ASP.NET Example</title>

009. <style type="text/css">

010. /** Customize the demo canvas */

011. #example .demo-container {

012. padding: 28px 0;

013. width: 882px;

014. height: 330px;

015. background: transparent url("Images/background.png") top left no-repeat;

016. position: relative;

017. }

018.

019. #example .demo-container h2 {

020. margin: 0 -30px 15px;

021. padding: 25px 30px 0;

022. color: #ffffff;

023. background: #4ba2d1;

024. font-size: 36px;

025. line-height: 1;

026. }

027.

028. .demo-container h2 sup {

029. font-size: 14px;

030. line-height: 1;

031. }

032.

033.

034. .demo-container .qsf-fb {

035. padding: 30px;

036. width: 327px;

037. overflow: hidden;

038. }

039.

040. .demo-container .qsf-fb ul {

041. margin: 0;

042. padding: 0;

043. list-style-type: none;

044. }

045.

046. .demo-container .qsf-fb label {

047. width: auto;

048. display: block;

049. }

050.

051. .demo-container .qsf-fb .buttons {

052. margin-top: 13px;

053. }

054.

055.

056. .demo-container .preview {

057. width: 495px;

058. height: 331px;

059. position: absolute;

060. top: 28px;

061. left: 387px;

062. }

063.

064. /* Customize uploaded file name */

065. html .RadUpload .ruUploadProgress {

066. display: inline-block;

067. max-width: 200px;

068. overflow: hidden;

069. text-overflow: ellipsis;

070. white-space: nowrap;

071. vertical-align: top;

072. }

073.

074. html div.photo-upload {

075. font-size: 12px;

076. }

077. </style>

078.</head>

079.

080.<body>

081. <form id="form1" runat="server">

082. <telerik:RadScriptManager ID="RadScriptManager1" runat="server">

083. <Scripts>

084. <asp:ScriptReference Assembly="Telerik.Web.UI" Name="Telerik.Web.UI.Common.Core.js" />

085. <asp:ScriptReference Assembly="Telerik.Web.UI" Name="Telerik.Web.UI.Common.jQuery.js" />

086. <asp:ScriptReference Assembly="Telerik.Web.UI" Name="Telerik.Web.UI.Common.jQueryInclude.js" />

087. </Scripts>

088. </telerik:RadScriptManager>

089. <telerik:RadSkinManager ID="RadSkinManager1" runat="server" ShowChooser="true" />

090. <telerik:RadFormDecorator RenderMode="Lightweight" runat="server" DecoratedControls="Buttons, TextBox" />

091.

092. <div class="demo-container no-bg">

093. <div class="qsf-demo-canvas" id="qsfexWrapper">

094. <div class="qsf-fb">

095. <h2>Dream Holiday <sup>Contest</sup></h2>

096. <ul>

097. <li>

098. <label>Upload a photo of your dream holiday:</label>

099. <telerik:RadAsyncUpload RenderMode="Lightweight" CssClass="photo-upload" runat="server" ID="RadAsyncUpload1" OnClientFileUploaded="onClientFileUploaded" PostbackTriggers="RadButton1"

100. MaxFileInputsCount="1" AllowedFileExtensions=".jpg" Skin="Outlook" />

101. </li>

102. </ul>

103.

104. <p class="buttons">

105. <asp:Button runat="server" ID="RadButton1" Text="Submit your picture and information" OnClientClick="updatePictureAndInfo(); return false;" />

106. </p>

107. </div>

108.

109. <telerik:RadBinaryImage runat="server" ID="RadBinaryImage1" ImageUrl="images/blank.png"

110. Width="495" Height="331" ResizeMode="Fit" AlternateText="No picture available"

111. CssClass="preview"></telerik:RadBinaryImage>

112. </div>

113. <telerik:RadScriptBlock ID="RadScriptBlock1" runat="server">

114. <script type="text/javascript">

115. //<![CDATA[

116. Sys.Application.add_load(function () {

117. window.upload = $(".RadAsyncUpload");

118. window.button = $("#RadButton1");

119. demo.initialize();

120. });

121.

122.

123. //]]>

124. </script>

125. </telerik:RadScriptBlock>

126. <script type="text/javascript">

127. (function () {

128. var $;

129. var upload;

130. var button;

131. var demo = window.demo = window.demo || {};

132.

133. demo.initialize = function () {

134. $ = $telerik.$;

135. button = window.button;

136. upload = window.upload;

137. };

138.

139. window.onClientFileUploaded = function (sender, args) {

140. button.removeAttr('disabled');

141. };

142.

143. window.updatePictureAndInfo = function () {

144. var uploadedRows = upload.find(".ruUploadSuccess");

145. if (uploadedRows.length > 0) {

146. alert('postback');

147. __doPostBack('RadButton1', 'RadButton1Args');

148. }

149. else {

150. alert("Please select a picture/country");

151. }

152. };

153.

154.

155. })();

156. </script>

157. </div>

158.

159. </form>

160.</body>

161.</html>

And the VB.net code

01.Imports System

02.Imports System.Drawing

03.

04.Partial Class TestUpload

05. Inherits System.Web.UI.Page

06.

07. Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load

08.

09. If (Not IsPostBack) Then

10. RadButton1.Enabled = False

11. Else

12.

13. RadButton1.Enabled = True

14. End If

15.

16. End Sub

17.

18. Protected Sub FileUploaded() Handles RadAsyncUpload1.FileUploaded

19.

20. Dim bitmapImage As Bitmap = ResizeImage(RadAsyncUpload1.UploadedFiles(0).InputStream)

21. Dim stream As System.IO.MemoryStream = New System.IO.MemoryStream()

22. bitmapImage.Save(stream, System.Drawing.Imaging.ImageFormat.Bmp)

23. RadBinaryImage1.DataValue = stream.ToArray()

24.

25. End Sub

26.

27. Protected Sub RadButton1_Click() Handles RadButton1.Click

28.

29.

30. End Sub

31.

32. Public Function ResizeImage(ByVal stream As IO.Stream) As Bitmap

33. Dim originalImage As System.Drawing.Image = Bitmap.FromStream(stream)

34.

35. Dim height As Integer = 331

36. Dim width As Integer = 495

37.

38. Dim scaledImage As New Bitmap(width, height)

39.

40. Using g As Graphics = Graphics.FromImage(scaledImage)

41. g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic

42. g.DrawImage(originalImage, 0, 0, width, height)

43. Return scaledImage

44. End Using

45.

46. End Function

47.

48.End Class

On line 99 of the aspx file you can see that the postbacktrigger is set to RadButton1. RadButton1 fires updatePictureAndInfo (line 143) I added a alert('postback') just before the __doPostBack() but this is never triggered.

Now in the VB file. If i were to change RadButton1.enabled = False to Radbutton1.enabled = True (line 10). Then press the button after uploading a JPG image the postback alert is fired but I get a server error:

Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"

/> in configuration or <%@ Page EnableEventValidation="true" %> in a page.  For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them.  If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.

Any help? I need the function updatePictureAndInfo() to fire even when the submit button initially would be disabled.

Thanks

1 Answer, 1 is accepted

answered on 24 Aug 2016, 04:27 PM

ButtonDisableSample.zip

Hello Olaf,

I attached a modified version of your page. The issue is coming from disabling the asp:Button with ID "RadButton1" in the code behind, which leads to its ClientClick event not firing even though you remove its attribute in onClientFileUploaded. I changed the asp:Button to RadButton, so that I can use its client-side method set_enabled(true). Also note that you need to get a proper reference to the RadButton: window.button = $find("<%=RadButton1.ClientID%>");
After the changes the alert('postback') is displayed as expected.

Regards,
Ivan Danchev
Telerik by Progress

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