如何从数据库中检索img [英] How to Retriev img from database

问题描述

你好，

当我单击按钮(btnImgFrmDB)时，我开发了一个代码来显示数据库中的图像
它失败了，我从互联网上尝试了很多，但仍然是同样的问题.

Error: Parameter is not valid.error showing where i wrote the line in bold and underline

代码:

Hello there

I develop a code to show the image from my database when i click button(btnImgFrmDB)
it fail and i tried a lot from internet but still the same problem.

Error: Parameter is not valid.error showing where i wrote the line in bold and underline

Code:

private void btnImgFrmDB_Click_1(object sender, EventArgs e)
        {
            
           if (textImg.Text != "")
            {
                string sqlstr = "Select Image from SqlToImage where ImgName=''" + textImg.Text + "'' ";
                SqlConnection conn = new SqlConnection(constring);
                conn.Open();
                SqlCommand cmd = new SqlCommand(sqlstr, conn);
                object img = cmd.ExecuteScalar();
                byte[] MyImg = (byte[])img;
                Stream s = null;
                MemoryStream ms = new MemoryStream(MyImg);
                ms.Read(MyImg, 0, MyImg.Length);
                s = ms;                
                pictureBox1.Image = Image.FromStream(ms);
               //Also tried the below Code and having same problem

                byte[] MyData = new byte[2048];
                MemoryStream ms=null;
                while (dr.Read())
                {
                    ms = new MemoryStream((byte[])dr[0]);
                }
                    Stream s = ms;
                    s.Read(MyData, 0, 2048);
                    pictureBox1.Image=Image.FromStream(s);
                    myPictureBox.Image = Image.FromStream(ms);
                    ms.Close();

            }

推荐答案

您尝试以下代码:-

You try this code:-

private void button3_Click(object sender, EventArgs e)
        {
            if (textImg.Text != "")
            {
                string sql = "Select Image from SqlToImage where ImgName=''" + textImg.Text + "'' ";
                SqlConnection connection = new SqlConnection();
                connection.ConnectionString = connectionString;
                connection.Open();
                FileStream file;
                BinaryWriter bw;
                int bufferSize = 100;
                byte[] outbyte = new byte[bufferSize];
                long retval;
                long startIndex = 0;
                savedImageName = textImg.Text;
                SqlCommand command = new SqlCommand(sql, connection);
                SqlDataReader myReader = command.ExecuteReader(CommandBehavior.SequentialAccess);
                while (myReader.Read())
                {
                    //string fileName = @"c:\" +textImg.Text+ ".jpeg";
                    /*file = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.Write);
                    bw = new BinaryWriter(file);*/
                    file = new FileStream(savedImageName, FileMode.OpenOrCreate, FileAccess.Write);
                    bw = new BinaryWriter(file);
                    startIndex = 0;
                    retval = myReader.GetBytes(0, startIndex, outbyte, 0, bufferSize);
                    while (retval == bufferSize)
                    {
                        bw.Write(outbyte);
                        bw.Flush();
                        startIndex += bufferSize;
                        retval = myReader.GetBytes(0, startIndex, outbyte, 0, bufferSize);
                    }
                    bw.Write(outbyte, 0, (int)retval - 1);
                    bw.Flush();
                    bw.Close();
                    file.Close();
                }
                connection.Close();
                curImage = Image.FromFile(savedImageName);
                pictureBox1.Image = curImage;
                pictureBox1.Invalidate();
                connection.Close();
            }
            
        }

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