An implementation method of WebForm image watermark and image Verification code for ASP.

Both need to introduce namespaces: using System.Drawing;

First, the picture watermark

Front desk photoshuiyin.aspx Code:

<div><asp:fileupload id= "FileUpload1" runat= "Server"/><asp:button id= "Button1" runat= "Server" text= " Upload "/><br/><asp:image id=" Image1 "runat=" Server "/></div>

Background Photoshuiyin.aspx.cs Code:

protected void Page_Load (object sender, EventArgs e) {Button1.Click + = button1_click;} void Button1_Click (object sender, EventArgs e) {///1, making canvas System.Drawing.Image img = System.Drawing.Image.FromStream ( Fileupload1.filecontent); Graphics g = Graphics.fromimage (IMG);//Watermark Style: Draw something string a = "http://www.itnba.com";//font, size font f = new Font ("Blackbody", 30);//Yan Color Brush B = New SolidBrush (color.red);//0,0--begin to draw the position of the watermark G. DrawString (A, F, B, 0, 0);//save path of String path = "images/" + fileupload1.filename;img. Save (path);//Show Image1.imageurl = path in the image control, Server.MapPath}

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Second, the Image verification code

Front desk photoyanzhengma.aspx Code:

<form id= "Form1" runat= "Server" ><div> User name: <asp:textbox id= "TextBox1" runat= "Server" ></asp: textbox><br/> Password: <asp:textbox id= "TextBox2" runat= "server" ></asp:textbox><br/> Verification Code:< Asp:textbox id= "TextBox3" runat= "Server" ></asp:textbox><asp:image id= "Image1" runat= "Server" Imageurl= " Yzm.aspx "/><asp:label id=" Label1 "runat=" Server "text=" Label "></asp:label><br/><asp: Button id= "Button1" runat= "Server" text= "button"/></div></form></body>

protected void Page_Load (object sender, EventArgs e) {Random r = new random (); string aaa = "Abcdefghijklmnopqrstuvwxyzabcde FGHIJKLMNOPQRSTUVWXYZ1234567890 ";//Generate canvas Bitmap img = new Bitmap (80, 30);//canvas background color generic combination list<color> Clist = new List <Color> (); Clist.add (Color.yellow); Clist.add (Color.green); Clist.add (Color.Blue); Clist.add (Color.aqua); Clist.add (Color.orange); Clist.add (Color.pink); Graphics g = Graphics.fromimage (img); G.fillrectangle (New SolidBrush (Clist[r.next (0, Clist.count)]), 0, 0, 80, 30);// Randomly generated verification code combination string str = ""; for (int i = 0; I < 4; i++) {str + = AAA. Substring (R.next (0, AAA). Length), 1);} session["YZM"] = str; Font f = new Font ("Blackbody", 20); Brush B = new SolidBrush (color.red);//Generate G. DrawString (str, F, B, 10, 0);//Add interference line for (int i = 0; i < R.next (6); i++) {Brush bb = new SolidBrush (clist[r.next (0, C List. Count)]); Pen p = new Pen (BB, 1), G.drawline (p, r.next (0, N), R.next (0, +), R.next (0, N), R.next (0, 30));} Save complete IMG. Save (Response.outputstream, System.Drawing.Imaging.IMAGEFORMAT.JPEG); Response.End ();}


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