Error Message:

 Unable to update the EntitySet 'TableName' because it has a DefiningQuery and no <InsertFunction> element exists in the <ModificationFunctionMapping> element to support the current operation.

Solution:

Make sure that table Primary key column. If not add one, that should fix this error

When button is disabled, it’s not-clickable in all browsers. However in Firefox and Chrome, the button looks enabled, though the user cannot click it.

Reason:

From W3Scholl, "Enabled" Property isn't standard property of XHTML 4.

Solution:

You can modify the way they look with CSS

button[disabled] { 
 color:Grey;
/* Add other  styles here for disable button */ 
} 

If you are getting following error after converting asp.net project to latest version..

To access local IIS Web sites, you must install the following IIS components: Internet Information Services IIS 6 Metabase and IIS 6 Configuration Compatibility

Try this solution:

open Control Panel, click Programs and Features

Expand Web Management Tools, expand IIS 6 Management Compatibility, and then select the IIS 6 Metabase and IIS 6 configuration compatibility check box.

Expand World Wide Web Services, expand Application Development Features, and then select the ASP.NET check box.

To enable Visual Studio to debug applications, you must configure IIS 7.0 with the Windows Authentication module. Expand World Wide Web Services, expand Security, and then select the Windows Authentication check box.

Reference: http://msdn.microsoft.com/en-us/library/aa964620.aspx

            string s ="45";
            int i;
            bool isNum = int.TryParse(s.ToString(), out i); 
 
            if (isNum)
                Response.Write(i); //integer 
            else
                Response.Write("Not an interger");

            //hide header column
            GridView1.HeaderRow.Cells[0].Visible = false;

            //hide column in data rows
            foreach (GridViewRow row in GridView1.Rows)
            {
                row.Cells[0].Visible = false;
            }

Make sure you have indicated that a Web service can be invoked from script..

    [System.Web.Script.Services.ScriptService]
    public class AutoCompleteService : System.Web.Services.WebService
    {
 
        //[WebMethod]
        //public string HelloWorld()
        //{
        //    return "Hello World";
        //}
    }

I came across a bug with Google chrome ver 1.0.154.43 while answering a problem in asp.net forums.

Problem:

Chrome browser ignores "onblur" event function for input box while it has Required field validator attached to it . Check this code..

  <input id="txt1" runat="server" type="text" maxlength="16" style="width: 127px" onblur= "formatSSN();"/>

  <asp:RequiredFieldValidator ID="Rfssn" runat="server" ControlToValidate="txt1" Display="None" ErrorMessage="SSN" 

     SetFocusOnError="True" EnableViewState="False">

  </asp:RequiredFieldValidator>

  <script language="javascript" type="text/javascript">

   function formatSSN() 

  {

    var ssn = document.getElementById("txt1").value;

    if(ssn.length == 9) 

        {

            document.getElementById("txt1").value= ssn.substring(0, 3) +"-" + ssn.substring(3, 5) + "-" + ssn.substring(5, 9); 

            return false;

        }

  }

  </script> 

The code works fine in IE6/7 & FireFox3, but not in Google chrome .

Solution:

I think the problem is with required field validator's SetFocusOnError property. Setting SetFocusOnError="false" for Rfv will fix it in chrome.

Here is an example to validate Fileupload control. This validation will check user to upload files of particular type/extension.

Client side validation:

<asp:FileUpload ID="UploadFile" runat="server" />
<asp:Button Text="Save" ID="btnSave" runat="server" OnClientClick="javascript:return ValidateUpload();" />     
 <script type="text/javascript" language="javascript">
    function ValidateUpload()
            {           
                var Upload_file = document.getElementById('<%= UploadFile.ClientID %>');                
                var myfile = Upload_file.value;               
                if(myfile.indexOf("doc")>0)
                {
                 alert('Valid Format');
                }
                else
                {
                 alert('Invalid Format');
                }            
            }
 </script>
Validating with RegularExpression validator:

<asp:FileUpload ID="UploadFile" runat="server" />
<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ErrorMessage="Only Doc files are allowed" 
ControlToValidate="UploadFile" ValidationExpression="^(([a-zA-Z]:)|(\\{2}\w+)\$?)(\\(\w[\w].*))+(.doc|.DOC)$">
</asp:RegularExpressionValidator>

In this example, I checked  ".doc" file type but you can use this example for any file type. Just replace ".doc" with file type you would  like to check( "Xml", "wmv"...).

Microsoft is going to make jQuery part of the official dev platform. JQuery will come with Visual Studio in the long term, and in the short term it'll ship with ASP.Net MVC. It is truly good news for ASP.Net developers

What is jQuery?

jQuery is a lightweight open source JavaScript library.

From jQuery website..

jQuery is a fast and concise JavaScript Library that simplifies HTML document traversing, event handling, animating, and Ajax interactions for rapid web development.

Blogs posts by Scott Guthrie and Scott Hanselman on this topic.

I see questions asked frequently about FireFox rendering problems in Asp.Net forums.

What is "rendering engine"?

A rendering engine, also known as a layout engine, is the code that tells the browser how to display web content and available style information in the browser window

Here are some options to solve those:

1. Always check  rendered web pages for XHTML compatibility using the W3C tests at   http://validator.w3.org . Most issues will fixed by fixing all non standards compliant HTML.
2. Set clientTarget="UpLevel" in Page Directive. This will override automatic detection of browser capabilities and specifies how a page renders for particular browser clients.
3. Here is link to a guide to make your page as accessible as possible.   http://www.anybrowser.org/campaign/abdesign.html