Unsafe code may only appear if compiling with /unsafe in VisualStudio 2005

Hi,
Here is the error which i got when using unsafe code
Unsafe code may only appear if compiling with /unsafe
Here is the solution for the above error
Add the following line under system.codedom /compilers
compiler language="C#;cs;csharp" extension=".cs" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" compilerOptions="/unsafe" /

UnSafe Code in C#

Hi,
Here is some details about Unsafe in C#
Unsafe code is code which does not executed under full control of CLR. It can cause some problems therefore each use must be marked as "unsafe".
...
unsafe
{
...
// unsafe context: can use pointers here
...
}
...
Generally speaking when you write any program in C# you create managed code. Managed code is executed under the control of Common Language Runtime (CLR). CRL causes that programmer do not need to manage memory and take care about memory's allocation and deallocation. CLR also allows you to write what is called 'unsafe code'.

Advantages:

• Performance and flexibility, by using pointer you can access data and manipulate it in the most efficient way possible.
• Compatibility, in most cases we still need to use old windows APIs, which use pointers extensively. Or third parties may supply DLLs that some of it’s functions need pointer parameters. Although this can be done by using DLLImport and System.IntPtr class, but in some cases it’s just much simpler to use pointer.
• Memory Addresses, there is no way to know the memory address of some data without using pointers.

Disadvantages:

• Complex syntax, to use pointers you need to go throw more complex syntax than we used to experience in C#.
• Harder to use, you need be more careful and logical while using pointers, miss using pointer might lead to the following:
• Overwrite other variables.
• Stack overflow.
• Access areas of memory that doesn’t contain any data as they do.
• Overwrite some information of the code for the .net runtime, which will surely lead you application to crash.
• Type-safety, using pointers will cause the code to fail in the .net type-safety checks, and of course if your Security policy don’t allow non type-safety code, then the .net framework will refuse to execute it.

Face Detection in Webapplication asp.net c#

Hi,
Here is the web application to detect the face on the image .Face Detection is does by open CV (open source Computer vision).

It is a library programming unit aimed at facial Recognition, motion detection . Download open CV here http://www.brothersoft.com/opencv-20868.html and install it Here is the link for face detection in windows application .http://www.codeproject.com/KB/library/eyes.aspx?fid=990485&df=90&mpp=25&noise=3&sort=Position&view=Quick&fr=51&select=2502155.The code that Modified from window application to web application.
To execute the application
Create Images Folder in the path of your website , place sample image as test.jpg .

Here is the code for aspx page
Add the following controls : file upload , Button,Image , HiddenField

Here is the code for aspx.cs page
public partial class _Default : System.Web.UI.Page
{
private string fileName;
private Guid imageId;
private Bitmap lastPic;
private clsFaceDetectionWrapper objFaceDetector = null;
private Pen myPen = new Pen(Color.Red, 2.0f);
Graphics picGraphics;
Graphics g;
private string filePath;
protected void Page_Load(object sender, EventArgs e)
{
objFaceDetector = clsFaceDetectionWrapper.GetSingletonInstance();
detectedImage.ImageUrl = Server.MapPath("./images/output.jpg");
}

void DrawRectangle(int lx, int ly, int rx, int ry)
{
g.DrawRectangle(myPen, lx, ly, rx - lx, ry - ly);
}
void DrawCross(int x, int y)
{
}

protected void detectButton_Click(object sender, EventArgs e)
{
imageId = new Guid();
imageId = Guid.NewGuid();
if (imageUpload.HasFile)
{
fileName = imageUpload.FileName.ToString().
Substring(imageUpload.FileName.ToString().LastIndexOf("."));
}
if (fileName.ToLower() == ".jpg" || fileName == ".gif" || fileName == ".jpeg" ||fileName == ".bmp" || fileName == ".png" || fileName == ".tif")
{
if (imageUpload.FileName != "")
{
pathHiddenField.Value = Server.MapPath("./images/" + imageId + "_" + imageUpload.FileName);
imageUpload.PostedFile.SaveAs(Server.MapPath("./images/" + imageId + "_" + imageUpload.FileName));
}
}
lastPic = new Bitmap(pathHiddenField.Value);
g = Graphics.FromImage(lastPic);
// here is the path to plave the cascade folder in the specified path.If Possible place the path cascade file in the execution path else modiy the face locatormethod and its coressponding dependabale method to get the path as arguments
String path = Server.MapPath("./XML/");
if (lastPic != null)
{
int faces = objFaceDetector.WrapDetectFaces(lastPic,path);

unsafe
{
int lx, ly, rx, ry, res;
for (int f = 0; f < faces; f++)
{
objFaceDetector.WrapGetFaceCordinates(f, &lx, &ly, &rx, &ry); g.DrawRectangle(myPen, lx, ly, rx, ry);
}
Response.ContentType = "image/jpeg";
lastPic.Save(Server.MapPath("./Images/Test.jpg"), ImageFormat.Jpeg); } detectedImage.ImageUrl = Server.MapPath("./Images/Test.jpg"); detectedImage.DataBind();
g.Save();
lastPic.Dispose();
g.Dispose();
}
}