在 c# 中更新带有文本的图像后从数据库加载图像时参数无效

Question

我有一个学生表，其中一个图像字段是学生 ID，通过将学生信息放在 png 文件中创建的学生 ID 并保存在数据库中 这是将文本放在图像文件上并将其保存在数据库中的代码，它可以正常工作

byte[] pic=null;
//call the idcard image
    Bitmap bitMapImage = new System.Drawing.Bitmap(@"C:\Users\pary\Videos\login2\login\image\card.png");
Graphics graphicImage = Graphics.FromImage(bitMapImage);
graphicImage.SmoothingMode = SmoothingMode.AntiAlias;
graphicImage.DrawString(TxtNamestudent.Text,
  new Font("Arial", 10),
        SystemBrushes.WindowText, new Point(1500, 555));
graphicImage.DrawString(comdep.SelectedItem.ToString(),
   new Font("Arial", 10),
        SystemBrushes.WindowText, new Point(1550, 690));
graphicImage.DrawString(dateTimePicker1.Value.ToString("MM/dd/yyyy"),
   new Font("Arial", 10),
       SystemBrushes.WindowText, new Point(1250, 850));
graphicImage.DrawString(cmbBloodgroup.SelectedItem.ToString(),
   new Font("Arial", 10),
      SystemBrushes.WindowText, new Point(1780, 960));
graphicImage.DrawString(dateTimePicker2.Value.ToString("MM/dd/yyyy"),
   new Font("Arial", 10),
        SystemBrushes.WindowText, new Point(1300, 1100));
OpenFileDialog open = new OpenFileDialog();
open.Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp)|*.jpg; *.jpeg; *.gif; *.bmp";
// if (open.ShowDialog() == DialogResult.OK)
//{
// display image in picture box
//  Image secondimage = new Bitmap(open.FileName);
// Image bimap2 = ResizeImage(secondimage, 70, 100);
//Bitmap bimap2 = new Bitmap(secondimage, new Size(12, 15));
using (Graphics g = Graphics.FromImage(bitMapImage))
{
    //draw other image on top of main Image
    g.DrawImage(bimap2, new Point(170, 600));
     final = ResizeImage(bitMapImage, 500, 400);
    //save new image
     final.Save(@"C:\Users\pary\Videos\login2\login\image" + TxtNamestudent.Text + ".Jpg");
    pictureBox2.Image = final;
    pictureBox2.Height = final.Height;
    pictureBox2.Width = final.Width;
    imglocation = (@"C:\Users\pary\Videos\login2\login\image" + TxtNamestudent.Text + ".Jpg");
    FileStream fs = new FileStream(imglocation, FileMode.Open, FileAccess.Read);
    BinaryReader br = new BinaryReader(fs);
    pic = br.ReadBytes((int)fs.Length);
    //MemoryStream stream = new MemoryStream();
    //pic = stream.ToArray();

}

SqlConnection con = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\pary\Videos\login2\login\Database1.mdf;Integrated Security=True;User Instance=True");
//open the connetion
con.Open();
//write query

SqlCommand cmd = new SqlCommand(@"INSERT INTO Table4 (KurdName,EnglishName,Blood,Gender,Sale_Ladaekbwn,Sale_Darchun,PhoneNumber,Email,Qonax,Schul,Department,pic)
VALUES (N'" + TxtNamestudent.Text + "','" + Txtname.Text + "','" + cmbBloodgroup.SelectedItem.ToString() + "',N'" + Gender + "','" + dateTimePicker1.Value.ToString("MM/dd/yyyy") + "','" + dateTimePicker2.Value.ToString("MM/dd/yyyy") + "','" + textmobil.Text + "','" + TxtEmail.Text + "',N'" + combqonax.SelectedItem.ToString() + "',N'" + comskul.SelectedItem.ToString() + "',N'" + comdep.SelectedItem.ToString() + "', @pic )", con);
cmd.Parameters.AddWithValue("@pic", pic);
cmd.ExecuteNonQuery();
con.Close();

这是加载图像并将其放在图片框上的代码，它也可以正常工作

string date_birth = (myreader["Sale_Ladaekbwn"].ToString());
string date_issue = (myreader["Sale_Darchun"].ToString());
DateTime date1 = DateTime.Parse(date_birth);
DateTime date2 = DateTime.Parse(date_issue);
dateTimePicker1.Value = date1;
dateTimePicker2.Value = date2;
byte[] data = new byte[0];
data = (Byte[])(myreader["pic"]);

MemoryStream mem = new MemoryStream(data);
//mem.Seek(0, SeekOrigin.Begin);
// Bitmap img = (Bitmap)System.Drawing.Image.FromStream(mem);
mem.Write(data, 0, data.Length);
mem.Position = 0;
Bitmap bmp = new Bitmap(mem);
pictureBox2.Image= Image.FromStream(mem);
pictureBox2.SizeMode = PictureBoxSizeMode.StretchImage;
mem.Close();

上面的代码正在运行，它正在从数据库中加载图像并将其放入图片框中

我遇到的问题是当我尝试更新存储在数据库中的图像和信息时，这是更新数据库中 id 图像的代码

private void btn_update_Click(object sender, EventArgs e)
{

    byte[] pic = null;
    //call the idcard image
    Bitmap bitMapImage = new System.Drawing.Bitmap(@"C:\Users\pary\Videos\login2\login\image\card.png");
    Graphics graphicImage = Graphics.FromImage(bitMapImage);
    graphicImage.SmoothingMode = SmoothingMode.AntiAlias;
    graphicImage.DrawString(TxtNamestudent.Text,
       new Font("Arial", 10),
             SystemBrushes.WindowText, new Point(1450, 555));
    graphicImage.DrawString(comdep.SelectedItem.ToString(),
        new Font("Arial", 10),
             SystemBrushes.WindowText, new Point(1550, 690));
    graphicImage.DrawString(dateTimePicker1.Value.ToString("MM/dd/yyyy"),
       new Font("Arial", 10),
           SystemBrushes.WindowText, new Point(1200, 850));
    graphicImage.DrawString(cmbBloodgroup.SelectedItem.ToString(),
       new Font("Arial", 10),
          SystemBrushes.WindowText, new Point(1780, 960));
    graphicImage.DrawString(dateTimePicker2.Value.ToString("MM/dd/yyyy"),
        new Font("Arial", 10),
             SystemBrushes.WindowText, new Point(1300, 1100));
    OpenFileDialog open = new OpenFileDialog();
    open.Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp)|*.jpg; *.jpeg; *.gif; *.bmp";
    // if (open.ShowDialog() == DialogResult.OK)
    //{
    // display image in picture box
    //  Image secondimage = new Bitmap(open.FileName);
    // Image bimap2 = ResizeImage(secondimage, 70, 100);
    //Bitmap bimap2 = new Bitmap(secondimage, new Size(12, 15));
    using (Graphics g = Graphics.FromImage(bitMapImage))
    {
        //draw other image on top of main Image
        g.DrawImage(bimap2, new Point(170, 600));
        final = ResizeImage(bitMapImage, 500, 400);
        //save new image
        final.Save(@"C:\Users\pary\Videos\login2\login\image"+ TxtNamestudent.Text + ".Jpg");
        pictureBox2.Image = final;
        pictureBox2.Height = final.Height;
        pictureBox2.Width = final.Width;
        imglocation = (@"C:\Users\pary\Videos\login2\login\image" + TxtNamestudent.Text + ".Jpg");
        FileStream fs = new FileStream(imglocation, FileMode.Open, FileAccess.Read);
        BinaryReader br = new BinaryReader(fs);
        pic = br.ReadBytes((int)fs.Length);
        //MemoryStream stream = new MemoryStream();
        //pic = stream.ToArray();
    }




    SqlConnection con = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\pary\Videos\login2\login\Database1.mdf;Integrated Security=True;User Instance=True");
    con.Open();
    SqlCommand cmd = new SqlCommand(@"update Table4 set KurdName=
          N'" + TxtNamestudent.Text + "',EnglishName='" + Txtname.Text + "',Blood='" + cmbBloodgroup.SelectedItem.ToString() + "',Gender=N'" + Gender + "',Sale_Ladaekbwn='" + dateTimePicker1.Value.ToString("MM/dd/yyyy") + "',Sale_Darchun='" + dateTimePicker2.Value.ToString("MM/dd/yyyy") + "',PhoneNumber='" + textmobil.Text + "',Email='" + TxtEmail.Text + "',Qonax=N'" + combqonax.SelectedItem.ToString() + "',Schul=N'" + comskul.SelectedItem.ToString() + "',Department=N'" + comdep.SelectedItem.ToString() + "',pic='" + pic + "'  where( ID='" + numVal + "')", con);
    cmd.Parameters.AddWithValue("@pic", pic);
    cmd.ExecuteNonQuery();
    con.Close();

此代码正在更新 id 图像上的信息并保存它。出现问题我试图在更新后加载图像，它给了我“参数无效”异常。我使用相同的代码来加载图像。

string date_birth = (myreader["Sale_Ladaekbwn"].ToString());
string date_issue = (myreader["Sale_Darchun"].ToString());
DateTime date1 = DateTime.Parse(date_birth);
DateTime date2 = DateTime.Parse(date_issue);
dateTimePicker1.Value = date1;
dateTimePicker2.Value = date2;
byte[] data = new byte[0];
data = (Byte[])(myreader["pic"]);

MemoryStream mem = new MemoryStream(data);
mem.Write(data, 0, data.Length);
mem.Position = 0;
Bitmap bmp = new Bitmap(mem);
pictureBox2.Image= Image.FromStream(mem);
pictureBox2.SizeMode = PictureBoxSizeMode.StretchImage;
mem.Close();

它在“Bitmap bmp= new Bitmap(mem);”行中给了我错误

如果有人有任何想法，请告诉我我真的很感激，我下周有 viva。非常感谢。

Answer 1

我假设简单的问题在这里像 "',pic='" + pic + "' 应该被纠正为 "', pic= @pic where ID='" + numVal + "'", con);

这就是它没有正确更新的原因。仔细检查您的 UPDATE 命令语法，如果它有效，请尝试..

最后，您使用的动态查询很容易受到 David 建议的 SQL 注入攻击。

因此，上述简单修正第一次应用成功后，以后最好考虑参数化查询，例如如下，
参数的 DataType 最好也具体定义。

如果您的问题解决了，请标记为答案。

SqlCommand comm = new SqlCommand();
comm.Connection = conn;
comm.CommandText = "UPDATE Table4 SET KurdName= @k_KurdName, pic= @k_pic  WHERE Id= @k_Id";

var da = new SqlDataAdapter(comm);
da.SelectCommand.Parameters.Add(new SqlParameter("@k_KurdName", SqlDbType.NVarChar));
da.SelectCommand.Parameters["@k_KurdName"].Value = TxtNamestudent.Text;
da.SelectCommand.Parameters.Add(new SqlParameter("@k_pic", SqlDbType.Binary));
da.SelectCommand.Parameters["@k_pic"].Value = pic;
da.SelectCommand.Parameters.Add(new SqlParameter("@k_Id", SqlDbType.NVarChar));
da.SelectCommand.Parameters["@k_Id"].Value = numval;