Could not load file or assembly ‘AjaxControlToolkit’ or one of its dependencies. The parameter is incorrect. (Exception from HRESULT: 0×80070057 (E_INVALIDARG))

Solution:
Clear out the temporary framework files for your project in:
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\

Windows 7 users:
C:\Users\[username]\AppData\Local\Temp\Temporary ASP.NET Files\

For 64 bit systems with ‘Framework’ in the path the full path is:
C:\WINDOWS\Microsoft.NET\Framework64\v2.0.50727\Temporary ASP.NET Files\

All credit for this solution goes to SolutionCottage.com, http://www.solutioncottage.com/ShowSolution.aspx?solID=59

Here is an example:

<%= Html.TextBoxFor(model => model.Email, new { @class = "txtLarge" })%>

In asp.NET MVC I used _class it seems in MVC 2 you need to use the @ symbol.

The client needed at least one of the two fields filled out.

Given the existing DataAnnotations nothing fit the bill in this case. I ended up creating a custom validation attribute that is applied at the class level.

I based it off of the PropertiesMustMatchAttribute custom attribute that is included in the AccountModels.cs/vb file within the default ASP.NET MVC 2 application project template (just do a File->New ASP.NET MVC 2 Web Project within VS 2010 and look for this class).

First off in the ContactModel.cs I added:

using System.ComponentModel.DataAnnotations;
using System.Globalization;

[AttributeUsage(AttributeTargets.Class, AllowMultiple = true, Inherited = true)]
    public sealed class OneOrOtherFieldRequired : ValidationAttribute
    {
        private const string _defaultErrorMessage = "'{0}' or '{1}' are required.";
        private readonly object _typeId = new object();

        public OneOrOtherFieldRequired(string field1, string field2)
            : base(_defaultErrorMessage)
        {
            Field1 = field1;
            Field2 = field2;
        }

        public string Field1 { get; private set; }
        public string Field2 { get; private set; }

        public override object TypeId
        {
            get
            {
                return _typeId;
            }
        }

        public override string FormatErrorMessage(string name)
        {
            return String.Format(CultureInfo.CurrentUICulture, ErrorMessageString, Field1, Field2);
        }

        public override bool IsValid(object value)
        {
            PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(value);
            object field1 = properties.Find(Field1, true).GetValue(value);
            object field2 = properties.Find(Field2, true).GetValue(value);
            string valueAsString1 = field1 as string;
            string valueAsString2 = field2 as string;
            if (String.IsNullOrEmpty(valueAsString1) && String.IsNullOrEmpty(valueAsString2))
            {
                return false;
            }
            return true;
        }
    }

I then created in ContactModel.cs the ContactModel class.  In this class I have among other properties the two phone number properies: HomePhoneNumber and MobilePhoneNumber.

 [OneOrOtherFieldRequired("HomePhone", "MobilePhone", ErrorMessage="Please fill in either your home or mobile number.")]
    public class ContactModel
    {
       ...
        public String HomePhone { get; set; }
        public String MobilePhone { get; set; }

In the ContactController I have an action:

        [HttpPost]
        public ActionResult Index(Contact contact)
        {
            if (ModelState.IsValid)
            {
                contact.Store();
                contact.SendEmail();
                ViewData["ShowForm"] = false;
                return View();
            }
            ViewData["ShowForm"] = true;
            return View(contact);
        }

When creating the view make sure to create a strongly typed view on the ContactModel

In the View I add the validation summary to display the error message if the requirement isn’t fulfilled.

<%= Html.ValidationSummary(true, "Please correct invalid and required fields.") %>

Research: I have found there a quite a few ways to achieve this.  Some take advantage of the Excel interop, some create a .csv, some use third party tools, some use xml. Here is a good discussion I found on the topic at Stack Overflow, http://stackoverflow.com/questions/151005/create-excel-xls-and-xlsx-file-from-c.
All have pros and cons.

Solution: Here is what I have found to be the simplest way to read your dataset in an Excel file. First off, this doesn’t product a true Excel file, but it is something Excel can read into a table which often is all you need.

What I found is you can write the contents of a datagrid to an output stream that can be saved as a .xls file.

code snippet: I am using linq to bind to a datagrid

var registrations = from reg in db.Registrations
                    where reg.JumpPageId == int.Parse((String)e.CommandArgument)
                    orderby reg.TimeStamp descending
                    select reg;
HttpResponse response = HttpContext.Current.Response;

// first let's clean up the response.object
response.Clear();
response.Charset = "";

// set the response mime type for excel
response.ContentType = "application/vnd.ms-excel";
response.AddHeader("Content-Disposition", "attachment; filename=registrants.xls");

// create a string writer
using (StringWriter sw = new StringWriter())
{
    using (HtmlTextWriter htw = new HtmlTextWriter(sw))
    {
        // instantiate a datagrid
        DataGrid dg = new DataGrid();
        dg.DataSource = registrations;
        dg.DataBind();
        dg.RenderControl(htw);
        response.Write(sw.ToString());
        response.End();
    }
}
 

LIke I said, this doesn’t output a true Excel file so when you go to open it, you will be prompted a warning:

It is saying the contents of the file are in a different format than what the .xls extension says it is. 

Click Yes and it will open.

If you were to open this file in a text editor you will see that it really is just the datagrid html output.

Not the most elegant solution but it is a quick way to throw an Export to Excel button on a report page.

My next blog post will show how to create an Excel file using a third party tool.

Research: After Binging for a while I found that the issue was due to a javascript error.  If you VIew Source of the page, you’ll notice that the rendered html uses javascript to perform the PostBack.

<input style=”border-right-width: 0px; border-top-width: 0px; border-bottom-width: 0px; border-left-width: 0px” id=”imgButton” class=”submit” onclick=”javascript:WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions(&quot;imgButton&quot;, &quot;&quot;, false, &quot;&quot;, &quot;/quick-contact.aspx&quot;, false, false))” src=”/i/qcsubmit.gif” type=”image” name=”imgButton” />

I then was able to capture the javascript error in IE. *Sidenote, what is a good way to do this? I ended up putting my cursor in the form, hit enter and quickly clicked on the browser stop button. There must be a better way.

“Webform_PostbackOptions” is undefined.

Ok…. Why is that? I found this in the comments at a blog post on http://pocketnerd.blogspot.com/2008/01/webformpostbackoptions-is-undefined.html

“I was getting this error in a load balanced production environment, but once the network admin turned on sticky sessions, all the errors went away. I assume it was trying to load the .axd file from the other web server and perhaps that caused a security problem which didn’t allow the file to load. Not sure but just thought I’d share what fixed it for me. “

I don’t have server access when hosting in the Cloud.

The WebForm_PostBackOptions function should be in the WebResource.axd file that you’ll see is referenced in the html on load.

<script src=”/WebResource.axd?d=Ttwk99ZBtJ8argpvGbO64g2&amp;t=633750447951477990″ type=”text/javascript”></script>

I tried browsing to this file and this indeed was the issue, 404 Not Found.

Solution: I loaded the page locally. Viewed Source, grabbed the WebResource.axd and querystring, browsed to this file. This gave me the output of the javascript. I copied that all and placed it into a postbackfix.js file. I then referenced this js file on the page. Uploaded the new js and aspx files. Works now.

This took me a few hours of banging my head (not to Quit Riot) to figure out. Hope this helps someone else.

I couldn’t find anything out there that I liked so here is what I came up with. The approach I am about to describe will place the Feedback tab on every page that is using your Master Page.

I am using the ASP.NET AJAX Control Toolkit for the modal.

First we need to set the modal up.

1. Make sure you have the AjaxControlToolkit assembly in your project references.
2. Add the page directive for the Control Kit at the top of your Master Page:

   <%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="ajaxToolkit" %>
   

3. Add the ScriptManager to your Master Page:

   <asp:ScriptManager ID="ScriptManager1" runat="server" />
   

4. Place the Feedback tab on your site by adding it as an ASP.NET ImageButton and adding a cssclass to it:

   <asp:ImageButton ID="lbFeedback" CssClass="tab" runat="server" ImageUrl="images/feedback.gif" />
   

5. Add this styling to your css stylesheet:

   .tab{position: fixed; right: 0; top: 250px;}
   

   This will position the tab on the right of the browser window.

6. Now add the Feedback form inside a panel that will appear in the modal to the bottom of your Master Page just before the </form>.

   <asp:Panel ID="pnlModal" runat="server" CssClass="modal">
           <p>Thank you for taking the time to leave us
               feedback. Good or bad we want to know how your experience was at our
               establishment.</p>
           <p><label>Name:</label><br /><asp:TextBox ID="txtName" runat="server" /></p>
           <p><label>Email:</label><br /><asp:TextBox ID="txtEmail" runat="server" /></p>
           <p><label>Message:</label><br /><asp:TextBox ID="txtMessage" runat="server" TextMode="MultiLine" Columns="40" Rows="10" /></p>
           <asp:Button ID="btnSubmit" runat="server" Text="Submit"
               onclick="btnSubmit_Click" />
           <asp:Button ID="btnCancel" runat="server" Text="Cancel" />
       </asp:Panel>
   

7. Add the Modal Popup Extender control to handle the modal:

   <ajaxToolkit:ModalPopupExtender ID="mpe" runat="server" TargetControlID="lbFeedback" PopupControlID="pnlModal" BackgroundCssClass="modalbg" CancelControlID="btnCancel"></ajaxToolkit:ModalPopupExtender>
   

8. Lets add a Thank you message that is only visible after the feedback form is submitted. I add this at the top of the Master Page:

   <div id="thankyou" runat="server" visible="false" class="thankyoumessage">Thank you for leaving feedback</div>
   

We now have a non-functioning Feedback form appearing inside a modal when the Feedback tab is clicked.  A cancel button is there if they decide not too leave feedback after all.

By adding the ASP.NET Button control in the modal it will do a PostBack back to the page that can be handled in the Master Page’s code-behind.  In the button handler I add the logic to simply email the submitted form to a desired email.  See my previous post on how to do that.

At the end of the Submit Button handler I have a Page Redirect that sends the visitor back to the page they are on.  Two reasons for this:

1. In the redirect I pass a QueryString param to the page letting it know that Feedback has been submitted.  In the PageLoad of the Master Page I check for this param and if it is present display a Thank You at the top of the page.
2. Secondly I do a redirect so the visitor won’t do a refresh to get ride of the Thank You message, thus re-sending the feedback info again.

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack && !String.IsNullOrEmpty(Request.QueryString["fb"]))
        {
            // the feedback form has been filled out, display a thank you message.
            thankyou.Visible = true;
        }
    }

    /// <summary>
    /// Handle the feedback form submit
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void btnSubmit_Click(object sender, EventArgs e)
    {
        // add the logic to handle the submited form fields

        string currentPage = Request.Path;
        Response.Redirect(currentPage + "?fb=1");
    }

To sharpen it up a bit some final touches in the style sheet for the modal and the thank you message:

.thankyoumessage{background-color:#cc0000; color:#fff; padding:20px; font-size:3em; text-align:center}
.modal{background-color:#fff; border:solid 3px gray; padding:8px; width:350px; height:450px;}
.modalbg{filter: Alpha(Opacity=70); -moz-opacity:0.7; opacity: 0.7; width: 100%; height: 100%; background-color: #000000; position: absolute; z-index: 500; top: 0px; left: 0px;}

I’ve put together a simple example website with all this working for download here.

There certainly is more that can be added upon this such as making the thank you message only visible for 3 seconds.  But, I think this is a good foundation.

Here is an example of a basic contact form.

First set the smtp information in the web.config

<system.net>
 <mailSettings>
 <smtp>
 <network host="mail.emailsrvr.com" userName="info@mydomain.com" password="mypassword" port="25"/>
 </smtp>
 </mailSettings>
 </system.net>

I put this at the very bottom of the web.config just before the closing tag.

Note that the userName and password must be of a valid email address of the domain you are sending from. Make sure to set this up through their control panel.

I also add in the appSettings of the web.config the email addresses of whom to send it to and the subject line. Just best practices.

<appSettings>
 <add key="mailTo" value="joel@mydomain.com"/>
 <add key="mailSubject" value="Contact Form inquiry"/>
 </appSettings>

Now my example is of an asp.net web application in c#. I am going to assume everyone knows how to setup the page, lets go to the code-behind.

You will need to add these three lines to your using block.

using System.Web.Configuration;
using System.Text;
using System.Net.Mail;

The submit button handler:

 /// <summary>
 /// Handles the contact form submit
 /// </summary>
 /// <param name="sender"></param>
 /// <param name="e"></param>
 protected void imtbtnSubmit_Click(object sender, ImageClickEventArgs e)
 {
 StringBuilder body = new StringBuilder();
 body.AppendFormat("Company Name: {0}{1}", txtCompany.Text, Environment.NewLine);
 body.AppendFormat("Contact Name: {0}{1}", txtName.Text, Environment.NewLine);
 body.AppendFormat("Phone: {0}{1}", txtPhone.Text, Environment.NewLine);
 body.AppendFormat("Email: {0}{1}", txtEmail.Text, Environment.NewLine);
 body.AppendLine();
 body.AppendLine("Message");
 body.AppendLine(txtMessage.Text);

 MailMessage message = new MailMessage(txtEmail.Text, WebConfigurationManager.AppSettings["mailTo"], WebConfigurationManager.AppSettings["mailSubject"], body.ToString());

 SmtpClient client = new SmtpClient();
 client.Send(message);

 pnlForm.Visible = false;
 lblMessage.Visible = true;
 }

Pretty simple stuff, the import part is system.net in the web.config, making sure you have the correct host and port  and a valid email.

You would think they would have this in their knowledge base, but as of this writing they don’t. I hope this helps someone.

In the left nav is was just a list of the titles.  The titles were links to anchors in the main page since the actual articles were a bit lengthy.

The client only wanted 5 articles to be displayed per page.  So paging was needed.  I used two separate ListViews to display the news items.  Along with that each ListView had a  DataPager to handle the paging.

The trick was if a user clicked on page 2 in the left nav how would we update the main content ListView to move to page 2 as well?

To accomplish this I accessed the PagePropertiesChanging handler and updated both DataPager PageProperties.

So if a user clicked in the left nav the code-behind is:

protected void lvLeftNav_PagePropertiesChanging(object sender, PagePropertiesChangingEventArgs e)
{
    dpNews.SetPageProperties(e.StartRowIndex, e.MaximumRows, false);
    dpLeftNav.SetPageProperties(e.StartRowIndex, e.MaximumRows, false);
    BindNews();
 }

As you see I update both DataPagers.

Here is the code-behind for the main news content code-behind:

protected void lvNews_PagePropertiesChanging(object sender, PagePropertiesChangingEventArgs e)
{
    dpNews.SetPageProperties(e.StartRowIndex, e.MaximumRows, false);
    dpLeftNav.SetPageProperties(e.StartRowIndex, e.MaximumRows, false);
    BindNews();
}

I should mention that the BindNews() method handles binding both the Left Nav and Main News to the same News List<News>.

I’ve been asked this a few times now so I thought I would blog my solution to point others to this next time I am asked.

Often times people will create a simple search on their site. The most obvious way to do this is with a simple textbox and button.  You then handle the search when the button is clicked in the code-behind.

It may look something like this:

    protected void btnSearch_Click(object sender, EventArgs e)
    {
        if (!String.IsNullOrEmpty(txtSearch.Text.Trim()))
        {
            BindSearch(txtSearch.Text.Trim());
        }
    }

Pretty straight forward.  The problem here is you’re doing a postback to the same page.  You won’t have a history of the previous searches in your browser. After doing a search and you want to see what you had for results from the previous search and simply hit back in your browser you’ll see this

So what I have always done to avoid this is to simply do a Response.Redirect to the page instead of just calling the BindSearch() method and put the search term in the query string.

    protected void btnSearch_Click(object sender, EventArgs e)
    {
        if (!String.IsNullOrEmpty(txtSearch.Text.Trim()))
        {
            Response.Redirect("/Search.aspx?search=" + txtSearch.Text.Trim());
        }
    }

This is a pretty simple solution, does anyone else have a different way to handle this?

When dealing with a webform with an extraordinary amount of controls, ie. textboxes, dropdownlists, panels, etc. I’ve noticed that after x amount of controls have been added they are no longer registered in the designer.cs file. 

I notice this by first the control not showing up in intellisense when trying to use it in code-behind.  If I manually type it out I will still get a build error. 

So, at this point I have to manually register any new controls in the designer.cs file.  At the top of the file it says,

//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.

However it seems that they are never lost and now everything works fine.  I am not sure if this is normal behavior and this is what you are suppose to do, but so far it has worked for me.

Has anyone else seen this, does anyone know the exact amount of controls that you can add to a page before they are no longer registered in the designer.cs?