Tech blog

We faced a problem when we added some PDF files into our media library of ASP.NET MVC website and noticed that these files are not Published automatically.
So you need in Visual Studio to click on each PDF file and under Properties (F4) just choose

• Build Action=Content
• Copy to Output Directory=Copy Always

Comparison: ASP .NET WebForms vs MVC

It turns out that the slowness is caused by an IPv6 issue with DNS and can easily be resolved by turning IPv6 support off in Firefox while doing localhost testing.

To make the change do this:

1. type about:config in the address bar
2. locate the network.dns.disableIPv6 setting
3. double-click on it to set it to true.

This does the trick for the Firefox localhost issue on Vista and everything is running fast again.

1. If you want to host ASP.NET MVC on IIS7 don’t forget to copy also MVC DLLs to bin directory when publishing.
   • If you have ASP.NET 3.5 SP1 installed on server copy only System.Web.Mvc
   • If you don’t have ASP.NET 3.5 SP1 installed on server copy
     System.Web.Mvc
     System.Web.Routing
     System.Web.Abstractions
2. You need to copy also web.config that is under directory where your Views are – it is not included in your project by default so it will not be published. Copy this manually or include this web.config in your project and then Publish.

<%= Html.DropDownList(“Salutation”, (IEnumerable<SelectListItem>)ViewData["Salutation"])%>

We just did not use properties in our viewdata that had the same name as any of the dropdowns , so above example is wrong and it will not select value properly. Instead of this use something like this:

<%= Html.DropDownList(“Salutation”, (IEnumerable<SelectListItem>)ViewData["SalutationList"])%>

And in controller:

ViewData["SalutationList"] = new SelectList(userModel.Salutations, “Value”, “Title”, user.Salutation);

HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create("url");
request.Method = "HEAD";

bool exists;
try
{
    request.GetResponse();
    exists = true;
}
catch
{
   exists = false;
}

Intro

I am working on a project that includes ASP .NET MVC web site and Silverlight 2.0 application. Initialy a Visual Studio solution with both project types has been created. At the beginning, sample Silverlight application worked fine, then most of the time development was going on MVC side. Now, when development should continue on Silverlight side browser throws an error:

This blog post explains how the issue has been solved. Resolving issue step by step…

1.Check namespaces

App.xaml should have x:Class attributes formatted as “Namespace.ClassName” (e.g. “StudioBikini.ClientSide.App”).

Same namespace and class name should also appear in App.xaml.cs. Note that namespace and class name are separated in C# file while glued together in XAML.

2. Change project properties

When you change a namespace for App in either C# or XAML the Startup object value in properties still holds the previous value.
Right click on a project in Visual Studio and select Properties.
Click on the Startup object combobox should open a list of available startup object and select the Namespace.ClassName.

Also make sure that Generate Silverlight manifest file checkbox is checked and an existing manifest file is selected.

3. Check manifest file

Some text editors add 3 garbage bytes at the beginning of a file which represent encoding. Those three bytes are invisible by some editors and may cause xml parsing exception.
Remove Properties\AppManifest.xml file and create it again.

4. Other possibilities:

• Try to set assembly name and default namespace in the project properties to the same value. Namespace in properties should be the same as namespace in App.
• Try with relative or absolute uri or false uri – if .xap file cannot be found Silverlight plug-in returns error #2104, that is different than #2103. So #2103 indicates that file has been found.
• Clear browser’s cache (downloaded data) and reload the page with Silverlight.
• Turn off virus scanner, as some scanners block loading unknown or hidden extensions (I had problems with .xaml.js for Silverlight 1.0).
• If you are using object tag in html to load .xap file, try to change height in pixels (in case it works on IE7 but not in Firefox 3.0).
• There may be an old .xap build. Try to rebuild VS solution or delete bin and obj folders from all projects – those folders are generated again on next build.
• AppManifest.xml file can be read-only, usually happens when under a source control system (e.g. sourcesafe, svn), so check it out first.
• Finally, delete AppManifest.xml, create new one and paste next lines into the file:

<Deployment xmlns=”http://schemas.microsoft.com/client/2007/deployment”
xmlns:x=”http://schemas.microsoft.com/winfx/2006/xaml”>
<Deployment.Parts>
</Deployment.Parts>
</Deployment>

Solution

It appears that file was under Visual SourceSafe, problem with locked file. Solution has been found progressively, step by step as described above.

Another time, another project, same error. Problem with an included assembly reference – a Silverlight Class Library project with web service reference and Silverlight Application project with reference System.ServiceModel… Resolved by commeting code that uses System.ServiceModel (code when calling web service generated classes). Alternative is to use  release settings instead of debug.

Any other suggestions?

If you get an error:

Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server. The status code returned from the server was: 0

just add this code in HEAD section of your page/masterpage:

<script language="javascript" type="text/javascript">
Sys.WebForms.PageRequestManager.getInstance().add_endRequest(endRequest);
function endRequest(sender, args)
{
	// Check to see if there's an error on this request.
	if (args.get_error() != undefined)
	{
	  //$get('Error').style.visibility = "visible";
	  // Let the framework know that the error is handled,
	  // so it doesn't throw the JavaScript alert.
	  args.set_errorHandled(true);
	}
}
</script>

This is a tutorial from very nice Blog:

Hi, I saw many developers are asking this questions in different forums. Recently I saw this question on MSDN forum and I thought let me write a blog on this. I know many of us found this too easy however for new bees its bit hard.

In this article, I had used SQL Server 2005 as back end and C# as front end. SQL Server has “Image” data type to store the image. In Oracle and some other database you can use a data type which is used to store binary value (may be BLOB). I have created a simple aspx which has File upload control and a button. When user selects a file to upload, I am checking it for valid image type and converting it to array of Bytes. Then I will store that byte array into database. Below is the code,

if (objFileUpload.PostedFile !=null)
{
if (objFileUpload.PostedFile.ContentLength > 0)
{
HttpPostedFile objHttpPostedFile = objFileUpload.PostedFile;
if (CheckValidFileType(objHttpPostedFile.FileName))
{
int intContentlength = objHttpPostedFile.ContentLength;
byte[] bytImage =new Byte[intContentlength];
objHttpPostedFile.InputStream.Read(bytImage, 0, intContentlength);
}
}
}

Read Uploaded file (here Image) in Byte Array

Pass this Byte array to you DAL and use it for storing image in database. I am using Enterprise Library as DAL so my code will look like,

Database db =DatabaseFactory.CreateDatabase();
string sqlCommand ="StoredProcedureName";
DbCommand dbCommandWrapper = db.GetStoredProcCommand(sqlCommand);
db.AddInParameter(dbCommandWrapper,"@Image",DbType.Binary,bytImage );
try
{
db.ExecuteNonQuery(dbCommandWrapper);
}
catch {throw; }

Insert Image in to database

This is how you can store the Image in database. Retrieving the image is the same process. Write a SP which will return your image. Store this value in a Byte Array. Once you get the image in Byte array, you just have to write it on form as shown below,

Byte[] bytImage =Byte array retrieved from database.
if (bytImage !=null)
{
Response.ContentType = "image/jpeg";
Response.Expires = 0;
Response.Buffer =true;
Response.Clear();
Response.BinaryWrite(bytImage);
Response.End();
}


Code to display Byte array as Image on form.

To use this at multiple places in your application, you create a page to which you can pass ID of Image and it will retrieve image from database and create image. To do this copy paste above code in aspx.cs file. Now on every page you require to show this image take on that page and set its ImageURL property to the path of newly created user control. See the code below,

Image control on any aspx page (Lets say Sample.aspx).

string strURL ="~/ViewImage.aspx?ID= 1";
ViewImage.ImageUrl = strURL;

set Image URL for image control on code behind (Sample.aspx.cs)

You can see the image will be displayed in your page where you had put Image tag.
Happy Programing.

In HEAD section put this:

<script language="JavaScript">
function correctPNG() // correctly handle PNG transparency in Win IE 5.5 & 6.
{
     var arVersion = navigator.appVersion.split("MSIE")
     var version = parseFloat(arVersion[1])
     if ((version >= 5.5) && (document.body.filters))
     {
            for(var i=0; i<document.images.length; i++)
            {
                 var img = document.images[i]
                 var imgName = img.src.toUpperCase()
                 if (imgName.substring(imgName.length-3, imgName.length) == "PNG")
                 {
                        var imgID = (img.id) ? "id='" + img.id + "' " : ""
                        var imgClass = (img.className) ? "class='" + img.className + "' " : ""
                        var imgTitle = (img.title) ? "title='" + img.title + "' " : "title='" + img.alt + "' "
                        var imgStyle = "display:inline-block;" + img.style.cssText
                        if (img.align == "left") imgStyle = "float:left;" + imgStyle
                        if (img.align == "right") imgStyle = "float:right;" + imgStyle
                        if (img.parentElement.href) imgStyle = "cursor:hand;" + imgStyle
                        var strNewHTML = "<span " + imgID + imgClass + imgTitle
                        + " style=\"" + "width:" + img.width + "px; height:" + img.height + "px;" + imgStyle + ";"
                        + "filter:progid:DXImageTransform.Microsoft.AlphaImageLoader"
                        + "(src=\'" + img.src + "\', sizingMethod='scale');\"></span>"
                        img.outerHTML = strNewHTML
                        i = i-1
                 }
            }
     }  
}
</script>

And in onload event put this

<body onload="correctPNG();">