asp.net图片上传实例

第一、图片上传，代码如下：
xxx.aspx

 <td class="style1">
                <asp:fileupload id="fileupload1" runat="server"  />
                <asp:button id="button1" runat="server" text="上传一般图片" onclick="button1_click" />
            </td>
            <td class="style3">
                <asp:image id="image1" runat="server" height="200px" width="200px" />
            </td>

xxx.aspx.cs

 protected void button1_click(object sender, eventargs e)
        {
            for (int i = 0; i < request.files.count; i++)
            {
                httppostedfile file = request.files[i];
                if (file.contentlength > 0)
                {
                    if (file.contenttype.contains("image/"))
                    {
                        using (system.drawing.image img = system.drawing.image.fromstream(file.inputstream))
                        {
                            string filename = system.io.path.getfilename(file.filename);
                            string[] splitfilename = filename.split('.');
                            string atterfilename = datetime.now.tostring("yyymmddhhmmss")+"." + splitfilename[1];
                            img.save(server.mappath("/upload/" + atterfilename));

                            this.image1.imageurl = "upload/" + atterfilename;
                        }
                    }
                    else
                    {
                        response.write("<script>alert('该文件不是图片格式！');</script>");
                    }
                }
                else
                {
                    response.write("<script>alert('请选择要上传的图片');</script>");
                }

            }
        }

第二、添加文字水印的图片上传，代码如下：
xxx.aspx

 <td class="style1">
                <asp:fileupload id="fileupload2" runat="server" />
                <asp:button id="button2" runat="server" text="上传文字图片" onclick="button2_click" />
            </td>
            <td>
                <asp:image id="image2" runat="server" height="200px" width="200px" />
            </td>

xxx.aspx.cs

 protected void button2_click(object sender, eventargs e)
        {
            for (int i = 0; i < request.files.count; i++)
            {
                httppostedfile file = request.files[i];
                if (file.contentlength > 0)
                {
                    if (file.contenttype.contains("image/"))
                    {
                        using (system.drawing.image img = system.drawing.image.fromstream(file.inputstream))
                        {
                            using (graphics g = graphics.fromimage(img))
                            {
                                g.drawstring("我的图片", new font("宋体", 14), brushes.red, 0, 0);
                            }
                            string filename = system.io.path.getfilename(file.filename);
                            string[] splitfilename = filename.split('.');
                            string atterfilename = datetime.now.tostring("yyymmddhhmmss") + "." + splitfilename[1];
                            img.save(server.mappath("/upload/" + atterfilename));
                            this.image2.imageurl = "upload/" + atterfilename;
                        }
                    }
                    else
                    {
                        response.write("<script>alert('该文件不是图片格式！');</script>");
                    }
                }
                else
                {
                    response.write("<script>alert('请选择要上传的图片');</script>");
                }

            }
        }

第三、添加图片水印的图片上传，代码如下：
xxx.aspx

 <td class="style1">
                <asp:fileupload id="fileupload3" runat="server" />
                <asp:button id="button3" runat="server" text="上传水印图片" onclick="button3_click" />
            </td>
            <td>
                <asp:image id="image3" runat="server" height="200px" width="200px" />
            </td>

xxx.aspx.cs

protected void button3_click(object sender, eventargs e)
        {
            for (int i = 0; i < request.files.count; i++)
            {
                httppostedfile file = request.files[i];
                if (file.contentlength > 0)
                {
                    if (file.contenttype.contains("image/"))
                    {
                        string filename = file.filename;
                        using (system.drawing.image img = system.drawing.image.fromstream(file.inputstream))
                        {
                            using (system.drawing.image imgwater = system.drawing.image.fromfile(server.mappath("/img/czlogo.jpg")))
                            {
                                using (graphics g = graphics.fromimage(img))
                                {
                                    g.drawimage(imgwater, 0, 0);
                                }
                                string[] splitfilename = filename.split('.');
                                string atterfilename = datetime.now.tostring("yyymmddhhmmss") + "." + splitfilename[1];
                                img.save(server.mappath("/upload/" + atterfilename));
                                this.image3.imageurl = "upload/" + atterfilename;
                            }
                        }
                    }
                    else
                    {
                        response.write("<script>alert('该文件不是图片格式！');</script>");
                    }
                }
                else
                {
                    response.write("<script>alert('请选择要上传的图片');</script>");
                }
            }
        }

第四、上传图片浓缩图，代码如下：
xxx.aspx

 <td class="style1">
                <asp:fileupload id="fileupload4" runat="server" />
                <asp:button id="button4" runat="server" text="上传浓缩图片" onclick="button4_click" />
            </td>
            <td>
                <asp:image id="image4" runat="server" height="200px" width="200px" />
            </td>

xxx.aspx.cs

 protected void button4_click(object sender, eventargs e)
        {
            for (int i = 0; i < request.files.count; i++)
            {
                httppostedfile file = request.files[i];
                if (file.contentlength > 0)
                {
                    if (file.contenttype.contains("image/"))
                    {
                        using (system.drawing.image img = system.drawing.image.fromstream(file.inputstream))
                        {
                            using (system.drawing.image imgthumb = new bitmap(200, 100))
                            {
                                using (graphics g = graphics.fromimage(imgthumb))
                                {
                                    g.drawimage(img, new rectangle(0, 0, imgthumb.width, imgthumb.height), new rectangle(0, 0, img.width, img.height), graphicsunit.pixel);
                                }
                                string filename = file.filename;
                                string[] splitfilename = filename.split('.');
                                string atterfilename = datetime.now.tostring("yyymmddhhmmss") + "." + splitfilename[1];
                                img.save(server.mappath("/upload/" + atterfilename));
                                this.image4.imageurl = "upload/" + atterfilename;
                            }
                        }
                    }
                    else
                    {
                        response.write("<script>alert('该文件不是图片格式！');</script>");
                    }
                }
                else
                {
                    response.write("<script>alert('请选择要上传的图片');</script>");
                }
            }

        }