b/S----file upload, image watermark, verification code

File Upload:

//Change the relative path to an absolute path.
string absolutepath = Server.MapPath (relativepath);

FileUpload CONTROLS:
Properties:
FileName : File name
Hasfile:bool Whether the file is selected
filebytes: Binary data to upload a file
Method:
SaveAs (String absolute path): Upload, Save As.

one, upload to the hard disk folder
(i) Leaflets documents
The first step: Prepare the file and path:
Remove the file name from the client before
string fileName = Fileupload1.filename;

Prevent file names
filename = DateTime.Now.ToString ("yyyymmddhhmmsss") + filename;

Convert relative path to absolute path
String path = Server.MapPath ("uploads/" + fileName);

Step two: Perform the upload:
Upload
Fileupload1.saveas (path); parameter must root path

Attention:
1. How do I prevent file names?
2. How to prevent different users from the same point of time traditional one file name?
Each client login has its own ssesion space, plus session["user name" (or "key name") to differentiate.
(ii) Transfer of multiple documents:
Idea: Traverse all the FileUpload controls in the form and upload if you select a file

int index = 0;
foreach (Control ctrl in Form1. Controls)
{
If (Ctrl is FileUpload)
{
index++;
Get each upload control
FileUpload upload = Ctrl as FileUpload;
The upload control has the file selected.
if (upload. HasFile)
{
Make file path out
String path = Server.MapPath ("uploads/" + DateTime.Now.ToString ("YYYYMMDDHHMMSS") + index. ToString ("xx") + Upload. FileName);

Upload
Upload. SaveAs (path);
}
}
}

second, upload to the database image field:
(i) upload to the database
1. Do the operation code of the database. DA Data
The image field corresponds to the byte[] type in the program.

2. Do the code on the interface.
A. Remove the value of the interface
Fileupload1.filebytes-binary data for uploading files.
B. Send to the database

(b) find it out from the database and show it

Law one: Cons: Garbage files are generated
Generate a JPG on the server and assign the path of this JPG to the image control

Remove the data from the database
Pictureda da = new Pictureda ();
PictureData Data=da. Select (Convert.ToInt32 (TextBox1.Text));

Flow
String temp = Server.MapPath ("imag/temp.jpg");
FileStream fs = new FileStream (temp, filemode.create);
Fs. Write (data. Fill, 0, data. Fill.length);
Fs. Close ();
Show
Image1.imageurl = "Imag/temp.jpg"

Law II: Make a separate page to display the binary data of the picture. Assign this page to the image control.
New page:
string ids = request["id"]. ToString ();

PictureData data = new Pictureda (). Select (Convert.ToInt32 (IDs));
if (data!=null)
{
Byte[] Buff=data. Fill;
Response.OutputStream.Write (Buff,0,buff. Length);
Response.End ();
}

buttons to display pictures:
Image1.imageurl = "default2.aspx?id=" +textbox1.text;



uploading images and watermarks:
//One, from the upload data, converted into a picture object
Stream s = fileupload1.filecontent;
System.Drawing.Image img = System.Drawing.Image.FromStream (s);
//Second, the picture object to draw the watermark
//1. Making Pens
SolidBrush brush = new SolidBrush (color.yellow);
//2. Making Fonts
Font font = new Font ("Microsoft Jas Black", 18);
//3. Finding the drawing area
Graphics g = Graphics.fromimage (IMG);
//4. Determining where to start the drawing
float x = 0, y = 0;
SizeF size = g.measurestring ("http:\\www.hao123.com", font);
x = img. Width-size. Width;
y = img. Height-size. Height;
//5. Start Drawing
g.DrawString ("http:\\www.hao123.com", font, brush, x, y);

//Three, Picture object Save as hard drive up
string filename = Fileupload1.filename;
String path = Server.MapPath ("imag/" +datetime.now.tostring ("yyyyMMdd") + filename);
Img. Save (path);

Verification Code: Note using System.Drawing;
Using System.IO;

Verification code Page

public partial class yzm:system.web.ui.page{protected void Page_Load (object sender, EventArgs e) {//Create a picture        Bitmap img = new Bitmap (60, 30);        Generates a random number of string str = "abcdefghigklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";        Random random = new random ();        String code = ""; for (int i = 0; i < 4; i++) {int start = random. Next (str.            Length); Code + = str.        Substring (start, 1);        }//Put the random number on the picture//build pen SolidBrush brush = new SolidBrush (color.white);        Font font = new Font ("Song Body", 15);        Find the drawing area Graphics g = Graphics.fromimage (IMG);        Find the location//a. Apply White g.fillrectangle (brush, 0, 0, 60, 30) to the background of the picture; B. Change the brushes to a brush color.        Color = color.red;        Start Drawing g.drawstring (code,font,brush,0,0); Save the image to the output stream to IMG.    Save (Response.outputstream,system.drawing.imaging.imageformat.jpeg); }}

The main page does not write code, but imageurl= "yzm.aspx" Call Verification code page,onclick= "Changpic ()" JS code every Click to change the diagram.

<body>    <form id= "Form1" runat= "Server" >    <div>            Verification Code: <asp:textbox id= "TextBox1" runat= "Server" ></asp:TextBox>        <asp:image id= "Image1" runat= "Server" imageurl= "yzm.aspx"   Onclick= "Changpic ()"/>        <br/>        <asp:button id= "Button1" runat= "Server" text= "button"/>        </div>    </form></body>

Javascript:

<script language= "javascript" >        function changpic ()        {            var img = document.getElementById ("Image1 ");            Img.setattribute ("src", "yzm.aspx?id=" +math.random ());        }    </script>

B/S----file upload, image watermark, verification code