如何上传缩小尺寸的图片答案

【问题标题】：how to upload image with reduced size如何上传缩小尺寸的图片
【发布时间】：2011-10-04 17:27:34
【问题描述】：

我正在使用 asp.net fileupload 控件来上传图像，但在这里我想自动将大小重新调整为 250*200px。请建议我在我的代码中添加什么。我是asp.net的新手。

protected void Button1_Click(object sender, EventArgs e)
        {   string s =@"~\img\"+FileUpload1.FileName;
            FileUpload1.PostedFile.SaveAs(Server.MapPath(s));


          }

【问题讨论】：

标签： asp.net

【解决方案1】：

我还发现这段代码对调整大小很有用

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Data.SqlClient;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
using System.Drawing;

public partial class ImageUpload : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void btnUpload_Click(object sender, EventArgs e)
    {

        string ImageName = txtName.Text;
        if (FileUpLoad1.PostedFile != null && FileUpLoad1.PostedFile.FileName != null)
        {

            string strExtension = System.IO.Path.GetExtension(FileUpLoad1.FileName);
            if ((strExtension.ToUpper() == ".JPG") | (strExtension.ToUpper() == ".GIF"))
            {
                // Resize Image Before Uploading to DataBase
                FileUpload fi = new FileUpload();
                fi = FileUpLoad1;

                System.Drawing.Image imageToBeResized = System.Drawing.Image.FromStream( fi.PostedFile.InputStream);
                int imageHeight = imageToBeResized.Height;
                int imageWidth = imageToBeResized.Width;
                int maxHeight = 120;
                int maxWidth = 160;
                imageHeight = (imageHeight * maxWidth) / imageWidth;
                imageWidth = maxWidth;

                if (imageHeight > maxHeight)
                {
                    imageWidth = (imageWidth * maxHeight) / imageHeight;
                    imageHeight = maxHeight;
                }

                Bitmap bitmap = new Bitmap(imageToBeResized, imageWidth, imageHeight);
                System.IO.MemoryStream stream = new MemoryStream();
                bitmap.Save(stream, System.Drawing.Imaging.ImageFormat.Jpeg);
                stream.Position = 0;
                byte[] image = new byte[stream.Length + 1];
                stream.Read(image, 0, image.Length);

                // Create SQL Connection 
                SqlConnection con = new SqlConnection();
                con.ConnectionString = ConfigurationManager.ConnectionStrings["Return_AuthorizationsConnectionString"].ConnectionString;

                 SqlCommand cmd = new SqlCommand();
                cmd.CommandText = "INSERT INTO Images(ImageName,Image) VALUES (@ImageName,@Image)";
                cmd.CommandType = CommandType.Text;
                cmd.Connection = con;

                SqlParameter ImageName1 = new SqlParameter("@ImageName", SqlDbType.VarChar, 50);
                ImageName1.Value = ImageName.ToString();
                cmd.Parameters.Add(ImageName1);

                SqlParameter UploadedImage = new SqlParameter("@Image", SqlDbType.Image, image.Length);
                UploadedImage.Value = image;
                cmd.Parameters.Add(UploadedImage);
                con.Open();
                int result = cmd.ExecuteNonQuery();
                con.Close();
                if (result > 0)
                    lblMessage.Text = "File Uploaded";
               GridView1.DataBind();
            }

            }

        }
}

【讨论】：

【解决方案2】：

在服务器上获取图像后，您可以将其调整大小保存，并删除原始图像。

仅用于调整大小的示例代码

http://weblogs.asp.net/gunnarpeipman/archive/2009/04/02/resizing-images-without-loss-of-quality.aspx

这是一个完整的项目，其中包含用于处理图像的源代码，包括调整大小。

http://www.codeproject.com/KB/web-image/ASPImaging1.aspx

【讨论】：