如何从我的网站更新现有图像? [英] how to update a existing image from my website?

问题描述

海

我想从我的网站更新数据库图像.在我的网页中，我具有文件上传，下拉列表和一个按钮字段.这是我的代码.

 受保护的 无效 Button1_Click(对象发​​件人，EventArgs e)
   {
       如果(FileUpload1.PostedFile！= 空&& FileUpload1.PostedFile.FileName！= " )
       {
           字节 [] imagesize = 新 字节 [ FileUpload1.PostedFile.ContentLength];
           HttpPostedFile UploadedImage = FileUpload1.PostedFile;
           uploadImage.InputStream.Read(imagesize， 0 ，( int )FileUpload1.PostedFile.ContentLength);
           SqlConnection con = 新 SqlConnection(ConfigurationManager.ConnectionStrings [" ].ConnectionString);
           con.Open();
            int  i = Convert.ToInt32(DropDownList1.SelectedItem.Text);
           SqlCommand cmd = 新 SqlCommand("  + i，con);
           SqlParameter param = 新 SqlParameter(" ，SqlDbType.Image，imagesize.Length)；
           cmd.Parameters.Add(uploadedImage);
           cmd.ExecuteNonQuery();
           MessageBox.Show(" );

       }
   }

实际上我不知道参数...而我的错误是

SqlParameterCollection仅接受非null的SqlParameter类型对象，而不接受HttpPostedFile对象.


请帮助我

解决方案

您不能将HttpPostadFile作为参数值发送到数据库.您将必须先将其转换为字节数组.

本文介绍了您需要了解的所有内容:
C#从数据库保存和加载图像 [ ^ ]

您的传递参数不正确.您创建了param参数，但是将uploadedImage添加到了命令cmd.
代替这个.

 SqlParameter param = 新 SqlParameter(" ，SqlDbType.Image，imagesize.Length)；
           cmd.Parameters.Add(uploadedImage);

试试，

 SqlParameter param = 新 SqlParameter(" ，SqlDbType.Image，imagesize)；
           cmd.Parameters.Add(param);

Hai

I want to update a database image from my website. in my web page i have file upload, dropdownlist,one button field. this is my code..

protected void Button1_Click(object sender, EventArgs e)
   {
       if (FileUpload1.PostedFile != null && FileUpload1.PostedFile.FileName != "")
       {
           byte[] imagesize = new byte[FileUpload1.PostedFile.ContentLength];
           HttpPostedFile uploadedImage = FileUpload1.PostedFile;
           uploadedImage.InputStream.Read(imagesize, 0, (int)FileUpload1.PostedFile.ContentLength);
           SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["wavoo"].ConnectionString);
           con.Open();
           int i =Convert.ToInt32(DropDownList1.SelectedItem.Text);
           SqlCommand cmd = new SqlCommand("update picture set image=@image  where ID=" + i, con);
           SqlParameter param = new SqlParameter("@Image", SqlDbType.Image, imagesize.Length);
           cmd.Parameters.Add(uploadedImage);
           cmd.ExecuteNonQuery();
           MessageBox.Show("sdfdf");

       }
   }

actually i don''t know about parameters... and my error is

The SqlParameterCollection only accepts non-null SqlParameter type objects, not HttpPostedFile objects.


Please help me

解决方案

You can''t send HttpPostadFile as a parameter value to your database. You will have to convert it to a bytearray first.

This article explains everything you''ll need to know:
C# Save and Load Image from Database[^]

Your passing parameter is incorrect. You created param parameter but adding uploadedImage to the command cmd.

Instead of this.

SqlParameter param = new SqlParameter("@Image", SqlDbType.Image, imagesize.Length);
           cmd.Parameters.Add(uploadedImage);

try,

SqlParameter param = new SqlParameter("@Image", SqlDbType.Image, imagesize);
           cmd.Parameters.Add(param );

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